This is v7 of the 'hist triggers' patchset, following feedback from
v6.
Changes from v6:
This version adds a new 'sym-offset' modifier as requested by Masami.
I implemented it as a modifier rather than using the trace option as
suggested, in part because I wanted to keep it all self-contained and
it seemed more consistent to just add it alongside the 'sym' modifier.
Also, hist triggers arent't really a tracer and therefore don't
directly tie into the option update/callback mechanism so making use
of it isn't as simple as a normal tracer.
I also changed the sort key specification to be stricter and signal an
error if the specified sort key wasn't found (rather than defaulting
to hitcount in those cases), also suggested by Masami. Thanks,
Masami, for your input!
Also updated the Documentation and tracing/README to reflect the
changes.
Changes from v5:
This version adds support for compound keys, along with the related
ability to sort using primary and secondary keys. This was mentioned
in previous versions as the last important piece that remained
unimplemented, and is now implemented. (I didn't have time to get to
the couple of enhancements suggested by Masami, but I expect to be
able to add those later on top of these.)
Because we now support compound keys and it's not immediately clear in
the output exactly which fields correspond to keys, the key(s),
compound or not, are now enclosed by curly braces.
The Documentation and README have been updated to reflect the changes,
and several new examples have been added to illustrate how to use
compound keys.
Also, the code was updated to work with the new ftrace_event_file,
etc, renaming in tracing/for-next.
Changes from v4:
This version addresses some problems and suggestions made by Daniel
Wagner - a lot of the code was reworked to get rid of the distinction
between keys and values, and as a result, both keys and values can be
used as sort keys. As suggested, it also allows 'val=' to be absent
in a trigger command - if no 'val' is specified, hitcount is assumed
and automatically used as the only val.
The map code was also separated out into a separate file,
tracing_map.c, allowing it to be reused. It also adds a second tracer
called function_hist that actually does reuse the code, as an RFC
patch.
Patch 01/10 [tracing: Update cond flag when enabling or disabling..]
is a fix for a problem noticed by Daniel and that fixes a problem in
existing trigger code and should be applied regardless of whether the
rest of the patchset is merged.
As mentioned, patch 10/10 is an RFC patch implementing a new tracer
based on the function tracer code. It's a fun little tool and is
useful for a specific problem I'm working on (and is also a nice test
of the tracing_map code), but is an RFC because first, I'm not sure it
would really be of general interest and secondly, it's POC-level
quality and I'd need to spend more time fixing it up to make it
upstreamable, but I don't want to waste my time if not.
There are a couple of important bits of functionality that were
present in v1 but not yet reimplemented in v5.
The first is support for compound keys. Currently, maps can only be
keyed on a single event field, whereas in v1 they could be keyed on
multiple keys. With support for compound keys, you can create much
more interesting output, such as for example per-pid lists of
syscalls or read counts e.g.:
# echo 'hist:keys=common_pid.execname,id.syscall:vals=hitcount' > \
/sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
# cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist
key: common_pid:bash[3112], id:sys_write vals: count:69
key: common_pid:bash[3112], id:sys_rt_sigprocmask vals: count:218
key: common_pid:update-notifier[3164], id:sys_poll vals: count:37
key: common_pid:update-notifier[3164], id:sys_recvfrom vals: count:118
key: common_pid:deja-dup-monito[3194], id:sys_sendto vals: count:1
key: common_pid:deja-dup-monito[3194], id:sys_read vals: count:4
key: common_pid:deja-dup-monito[3194], id:sys_poll vals: count:8
key: common_pid:deja-dup-monito[3194], id:sys_recvmsg vals: count:8
key: common_pid:deja-dup-monito[3194], id:sys_getegid vals: count:8
key: common_pid:emacs[3275], id:sys_fsync vals: count:1
key: common_pid:emacs[3275], id:sys_open vals: count:1
key: common_pid:emacs[3275], id:sys_symlink vals: count:2
key: common_pid:emacs[3275], id:sys_poll vals: count:23
key: common_pid:emacs[3275], id:sys_select vals: count:23
key: common_pid:emacs[3275], id:unknown_syscall vals: count:34
key: common_pid:emacs[3275], id:sys_ioctl vals: count:60
key: common_pid:emacs[3275], id:sys_rt_sigprocmask vals: count:116
key: common_pid:cat[3323], id:sys_munmap vals: count:1
key: common_pid:cat[3323], id:sys_fadvise64 vals: count:1
Related to that is support for sorting on multiple fields. Currently,
you can sort using only a primary key. Being able to sort on multiple
or at least a secondary key is indispensible for seeing trends when
displaying multiple values.
Changes from v3:
v4 fixes the race in tracing_map_insert() noted in v3, where
map.val.key could be checked even if map.val wasn't yet set. The
simple fix for that in tracing_map_insert() introduces the possibility
of duplicates in the map, which though rare, need to be accounted for
in the output. To address that, duplicate-merging code was added to
the map-printing code.
It was also pointed out that it didn't seem correct to include
module.h, but the fix for that has deeper roots and is being addressed
by a separate patchset; for now we need to continue including
module.h, though prompted by that I did some other header include
cleanup.
The functionality remains the same as v2, but this version no longer
tries to export and use bpf_maps, and more importantly removes the
associated GFP_NOTRACE/trace event hacks and kmem macros required to
work around the bpf_map implementation.
The tracing_map functionality is instead built on top of a simple
lock-free map algorithm originated by Dr. Cliff Click (see references
in the code for more details), which though too restrictive to be
general-purpose in its current form, functions nicely as a
special-purpose tracing map.
v3 also moves the hist triggers code into a separate file and puts it
all behind a new config option, CONFIG_HIST_TRIGGERS. It also merges
in the sorting code rather than keeping it as a separate patch.
This patchset also includes a couple other new and related triggers,
enable_hist and disable_hist, very similar to the existing
enable_event/disable_event triggers used to automatically enable and
disable events based on a triggering condition, but in this case
allowing hist triggers to be enabled and disabled in the same way.
- Added an insert check for val before checking the key associated with val
- Added code to merge possible duplicates in the map
Changes from v2:
- reimplemented tracing_map, replacing bpf_map with nmi-safe/lock-free map
- removed GPF_NOTRACE, kmalloc/free macros and event hacks needed by bpf_maps
- moved hist triggers from trace_events_trigger.c to trace_events_hist.c
- added CONFIG_HIST_TRIGGERS config option
- consolidated sorting code with main patch
Changes from v1:
- completely rewritten on top of tracing_map (renamed and exported bpf_map)
- added map clearing and client ops to tracing_map
- changed the name from 'hash' triggers to 'hist' triggers
- added new trigger 'pause' feature
- added new enable_hist and disable_hist triggers
- added usage for hist/enable_hist/disable hist to tracing/README
- moved examples into Documentation/trace/event.txt
- added ___GFP_NOTRACE, kmalloc/kfree macros, and conditional kmem tracepoints
The following changes since commit a497adb45b8691f7e477e711a1a4bd54748d64fe:
ring-buffer: Add enum names for the context levels (2015-05-29 10:39:08 -0400)
are available in the git repository at:
git://git.yoctoproject.org/linux-yocto-contrib.git tzanussi/hist-triggers-v7
http://git.yoctoproject.org/cgit/cgit.cgi/linux-yocto-contrib/log/?h=tzanussi/hist-triggers-v7
Tom Zanussi (10):
tracing: Update cond flag when enabling or disabling a trigger
tracing: Make ftrace_event_field checking functions available
tracing: Add event record param to trigger_ops.func()
tracing: Add get_syscall_name()
tracing: Add a per-event-trigger 'paused' field
trace: Add lock-free tracing_map
tracing: Add 'hist' event trigger command
tracing: Add enable_hist/disable_hist triggers
tracing: Add 'hist' trigger Documentation
ftrace: Add function_hist tracer
Documentation/trace/events.txt | 1131 ++++++++++++++++++++++++++++
include/linux/trace_events.h | 9 +-
kernel/trace/Kconfig | 14 +
kernel/trace/Makefile | 3 +
kernel/trace/trace.c | 69 ++
kernel/trace/trace.h | 88 ++-
kernel/trace/trace_events.c | 4 +
kernel/trace/trace_events_filter.c | 12 -
kernel/trace/trace_events_hist.c | 1407 +++++++++++++++++++++++++++++++++++
kernel/trace/trace_events_trigger.c | 149 ++--
kernel/trace/trace_functions_hist.c | 345 +++++++++
kernel/trace/trace_syscalls.c | 11 +
kernel/trace/tracing_map.c | 920 +++++++++++++++++++++++
kernel/trace/tracing_map.h | 143 ++++
14 files changed, 4221 insertions(+), 84 deletions(-)
create mode 100644 kernel/trace/trace_events_hist.c
create mode 100644 kernel/trace/trace_functions_hist.c
create mode 100644 kernel/trace/tracing_map.c
create mode 100644 kernel/trace/tracing_map.h
--
1.9.3
When a trigger is enabled, the cond flag should be set beforehand,
otherwise a trigger that's expecting to process a trace record
(e.g. one with post_trigger set) could be invoked without one.
Likewise a trigger's cond flag should be reset after it's disabled,
not before.
Signed-off-by: Tom Zanussi <[email protected]>
Signed-off-by: Daniel Wagner <[email protected]>
---
kernel/trace/trace_events_trigger.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 42a4009..4d2f3cc 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -543,11 +543,12 @@ static int register_trigger(char *glob, struct event_trigger_ops *ops,
list_add_rcu(&data->list, &file->triggers);
ret++;
+ update_cond_flag(file);
if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
+ update_cond_flag(file);
ret--;
}
- update_cond_flag(file);
out:
return ret;
}
@@ -575,8 +576,8 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
unregistered = true;
list_del_rcu(&data->list);
- update_cond_flag(file);
trace_event_trigger_enable_disable(file, 0);
+ update_cond_flag(file);
break;
}
}
@@ -1319,11 +1320,12 @@ static int event_enable_register_trigger(char *glob,
list_add_rcu(&data->list, &file->triggers);
ret++;
+ update_cond_flag(file);
if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
+ update_cond_flag(file);
ret--;
}
- update_cond_flag(file);
out:
return ret;
}
@@ -1344,8 +1346,8 @@ static void event_enable_unregister_trigger(char *glob,
(enable_data->file == test_enable_data->file)) {
unregistered = true;
list_del_rcu(&data->list);
- update_cond_flag(file);
trace_event_trigger_enable_disable(file, 0);
+ update_cond_flag(file);
break;
}
}
--
1.9.3
Make is_string_field() and is_function_field() accessible outside of
trace_event_filters.c for other users of ftrace_event_fields.
Signed-off-by: Tom Zanussi <[email protected]>
---
kernel/trace/trace.h | 12 ++++++++++++
kernel/trace/trace_events_filter.c | 12 ------------
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 4c41fcd..891c5b0 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1050,6 +1050,18 @@ struct filter_pred {
unsigned short right;
};
+static inline bool is_string_field(struct ftrace_event_field *field)
+{
+ return field->filter_type == FILTER_DYN_STRING ||
+ field->filter_type == FILTER_STATIC_STRING ||
+ field->filter_type == FILTER_PTR_STRING;
+}
+
+static inline bool is_function_field(struct ftrace_event_field *field)
+{
+ return field->filter_type == FILTER_TRACE_FN;
+}
+
extern enum regex_type
filter_parse_regex(char *buff, int len, char **search, int *not);
extern void print_event_filter(struct trace_event_file *file,
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 71511eb..245ee5d 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -917,18 +917,6 @@ int filter_assign_type(const char *type)
return FILTER_OTHER;
}
-static bool is_function_field(struct ftrace_event_field *field)
-{
- return field->filter_type == FILTER_TRACE_FN;
-}
-
-static bool is_string_field(struct ftrace_event_field *field)
-{
- return field->filter_type == FILTER_DYN_STRING ||
- field->filter_type == FILTER_STATIC_STRING ||
- field->filter_type == FILTER_PTR_STRING;
-}
-
static int is_legal_op(struct ftrace_event_field *field, int op)
{
if (is_string_field(field) &&
--
1.9.3
Some triggers may need access to the trace event, so pass it in. Also
fix up the existing trigger funcs and their callers.
Signed-off-by: Tom Zanussi <[email protected]>
---
include/linux/trace_events.h | 3 ++-
kernel/trace/trace.h | 6 ++++--
kernel/trace/trace_events_trigger.c | 35 ++++++++++++++++++-----------------
3 files changed, 24 insertions(+), 20 deletions(-)
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 1063c85..d70c0d2 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -423,7 +423,8 @@ extern int call_filter_check_discard(struct trace_event_call *call, void *rec,
extern enum event_trigger_type event_triggers_call(struct trace_event_file *file,
void *rec);
extern void event_triggers_post_call(struct trace_event_file *file,
- enum event_trigger_type tt);
+ enum event_trigger_type tt,
+ void *rec);
/**
* trace_trigger_soft_disabled - do triggers and test if soft disabled
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 891c5b0..8275db7 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1125,7 +1125,8 @@ struct event_trigger_data {
* @func: The trigger 'probe' function called when the triggering
* event occurs. The data passed into this callback is the data
* that was supplied to the event_command @reg() function that
- * registered the trigger (see struct event_command).
+ * registered the trigger (see struct event_command) along with
+ * the trace record, rec.
*
* @init: An optional initialization function called for the trigger
* when the trigger is registered (via the event_command reg()
@@ -1150,7 +1151,8 @@ struct event_trigger_data {
* (see trace_event_triggers.c).
*/
struct event_trigger_ops {
- void (*func)(struct event_trigger_data *data);
+ void (*func)(struct event_trigger_data *data,
+ void *rec);
int (*init)(struct event_trigger_ops *ops,
struct event_trigger_data *data);
void (*free)(struct event_trigger_ops *ops,
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 4d2f3cc..7011468 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -74,7 +74,7 @@ event_triggers_call(struct trace_event_file *file, void *rec)
list_for_each_entry_rcu(data, &file->triggers, list) {
if (!rec) {
- data->ops->func(data);
+ data->ops->func(data, rec);
continue;
}
filter = rcu_dereference_sched(data->filter);
@@ -84,7 +84,7 @@ event_triggers_call(struct trace_event_file *file, void *rec)
tt |= data->cmd_ops->trigger_type;
continue;
}
- data->ops->func(data);
+ data->ops->func(data, rec);
}
return tt;
}
@@ -104,13 +104,14 @@ EXPORT_SYMBOL_GPL(event_triggers_call);
*/
void
event_triggers_post_call(struct trace_event_file *file,
- enum event_trigger_type tt)
+ enum event_trigger_type tt,
+ void *rec)
{
struct event_trigger_data *data;
list_for_each_entry_rcu(data, &file->triggers, list) {
if (data->cmd_ops->trigger_type & tt)
- data->ops->func(data);
+ data->ops->func(data, rec);
}
}
EXPORT_SYMBOL_GPL(event_triggers_post_call);
@@ -752,7 +753,7 @@ static int set_trigger_filter(char *filter_str,
}
static void
-traceon_trigger(struct event_trigger_data *data)
+traceon_trigger(struct event_trigger_data *data, void *rec)
{
if (tracing_is_on())
return;
@@ -761,7 +762,7 @@ traceon_trigger(struct event_trigger_data *data)
}
static void
-traceon_count_trigger(struct event_trigger_data *data)
+traceon_count_trigger(struct event_trigger_data *data, void *rec)
{
if (tracing_is_on())
return;
@@ -776,7 +777,7 @@ traceon_count_trigger(struct event_trigger_data *data)
}
static void
-traceoff_trigger(struct event_trigger_data *data)
+traceoff_trigger(struct event_trigger_data *data, void *rec)
{
if (!tracing_is_on())
return;
@@ -785,7 +786,7 @@ traceoff_trigger(struct event_trigger_data *data)
}
static void
-traceoff_count_trigger(struct event_trigger_data *data)
+traceoff_count_trigger(struct event_trigger_data *data, void *rec)
{
if (!tracing_is_on())
return;
@@ -881,13 +882,13 @@ static struct event_command trigger_traceoff_cmd = {
#ifdef CONFIG_TRACER_SNAPSHOT
static void
-snapshot_trigger(struct event_trigger_data *data)
+snapshot_trigger(struct event_trigger_data *data, void *rec)
{
tracing_snapshot();
}
static void
-snapshot_count_trigger(struct event_trigger_data *data)
+snapshot_count_trigger(struct event_trigger_data *data, void *rec)
{
if (!data->count)
return;
@@ -895,7 +896,7 @@ snapshot_count_trigger(struct event_trigger_data *data)
if (data->count != -1)
(data->count)--;
- snapshot_trigger(data);
+ snapshot_trigger(data, rec);
}
static int
@@ -974,13 +975,13 @@ static __init int register_trigger_snapshot_cmd(void) { return 0; }
#define STACK_SKIP 3
static void
-stacktrace_trigger(struct event_trigger_data *data)
+stacktrace_trigger(struct event_trigger_data *data, void *rec)
{
trace_dump_stack(STACK_SKIP);
}
static void
-stacktrace_count_trigger(struct event_trigger_data *data)
+stacktrace_count_trigger(struct event_trigger_data *data, void *rec)
{
if (!data->count)
return;
@@ -988,7 +989,7 @@ stacktrace_count_trigger(struct event_trigger_data *data)
if (data->count != -1)
(data->count)--;
- stacktrace_trigger(data);
+ stacktrace_trigger(data, rec);
}
static int
@@ -1059,7 +1060,7 @@ struct enable_trigger_data {
};
static void
-event_enable_trigger(struct event_trigger_data *data)
+event_enable_trigger(struct event_trigger_data *data, void *rec)
{
struct enable_trigger_data *enable_data = data->private_data;
@@ -1070,7 +1071,7 @@ event_enable_trigger(struct event_trigger_data *data)
}
static void
-event_enable_count_trigger(struct event_trigger_data *data)
+event_enable_count_trigger(struct event_trigger_data *data, void *rec)
{
struct enable_trigger_data *enable_data = data->private_data;
@@ -1084,7 +1085,7 @@ event_enable_count_trigger(struct event_trigger_data *data)
if (data->count != -1)
(data->count)--;
- event_enable_trigger(data);
+ event_enable_trigger(data, rec);
}
static int
--
1.9.3
Add a utility function to grab the syscall name from the syscall
metadata, given a syscall id.
Signed-off-by: Tom Zanussi <[email protected]>
---
kernel/trace/trace.h | 5 +++++
kernel/trace/trace_syscalls.c | 11 +++++++++++
2 files changed, 16 insertions(+)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8275db7..a3efff3 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1317,8 +1317,13 @@ int perf_ftrace_event_register(struct trace_event_call *call,
#ifdef CONFIG_FTRACE_SYSCALLS
void init_ftrace_syscalls(void);
+const char *get_syscall_name(int syscall);
#else
static inline void init_ftrace_syscalls(void) { }
+static inline const char *get_syscall_name(int syscall)
+{
+ return NULL;
+}
#endif
#ifdef CONFIG_EVENT_TRACING
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 7d567a4..004c111 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -106,6 +106,17 @@ static struct syscall_metadata *syscall_nr_to_meta(int nr)
return syscalls_metadata[nr];
}
+const char *get_syscall_name(int syscall)
+{
+ struct syscall_metadata *entry;
+
+ entry = syscall_nr_to_meta(syscall);
+ if (!entry)
+ return NULL;
+
+ return entry->name;
+}
+
static enum print_line_t
print_syscall_enter(struct trace_iterator *iter, int flags,
struct trace_event *event)
--
1.9.3
Add a simple per-trigger 'paused' flag, allowing individual triggers
to pause. We could leave it to individual triggers that need this
functionality to do it themselves, but we also want to allow other
events to control pausing, so add it to the trigger data.
Signed-off-by: Tom Zanussi <[email protected]>
---
kernel/trace/trace.h | 1 +
kernel/trace/trace_events_trigger.c | 4 ++++
2 files changed, 5 insertions(+)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index a3efff3..8dcb77c 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1110,6 +1110,7 @@ struct event_trigger_data {
struct event_filter __rcu *filter;
char *filter_str;
void *private_data;
+ bool paused;
struct list_head list;
};
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 7011468..ecf65e1 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -73,6 +73,8 @@ event_triggers_call(struct trace_event_file *file, void *rec)
return tt;
list_for_each_entry_rcu(data, &file->triggers, list) {
+ if (data->paused)
+ continue;
if (!rec) {
data->ops->func(data, rec);
continue;
@@ -110,6 +112,8 @@ event_triggers_post_call(struct trace_event_file *file,
struct event_trigger_data *data;
list_for_each_entry_rcu(data, &file->triggers, list) {
+ if (data->paused)
+ continue;
if (data->cmd_ops->trigger_type & tt)
data->ops->func(data, rec);
}
--
1.9.3
Add tracing_map, a special-purpose lock-free map for tracing.
tracing_map is designed to aggregate or 'sum' one or more values
associated with a specific object of type tracing_map_elt, which
is associated by the map to a given key.
It provides various hooks allowing per-tracer customization and is
separated out into a separate file in order to allow it to be shared
between multiple tracers, but isn't meant to be generally used outside
of that context.
The tracing_map implementation was inspired by lock-free map
algorithms originated by Dr. Cliff Click:
http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable
http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf
Signed-off-by: Tom Zanussi <[email protected]>
---
kernel/trace/Makefile | 1 +
kernel/trace/tracing_map.c | 920 +++++++++++++++++++++++++++++++++++++++++++++
kernel/trace/tracing_map.h | 143 +++++++
3 files changed, 1064 insertions(+)
create mode 100644 kernel/trace/tracing_map.c
create mode 100644 kernel/trace/tracing_map.h
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 9b1044e..3b26cfb 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_TRACING) += trace_output.o
obj-$(CONFIG_TRACING) += trace_seq.o
obj-$(CONFIG_TRACING) += trace_stat.o
obj-$(CONFIG_TRACING) += trace_printk.o
+obj-$(CONFIG_TRACING) += tracing_map.o
obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
new file mode 100644
index 0000000..b748f6c
--- /dev/null
+++ b/kernel/trace/tracing_map.c
@@ -0,0 +1,920 @@
+/*
+ * tracing_map - lock-free map for tracing
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2015 Tom Zanussi <[email protected]>
+ *
+ * tracing_map implementation inspired by lock-free map algorithms
+ * originated by Dr. Cliff Click:
+ *
+ * http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable
+ * http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf
+ */
+
+#include <linux/slab.h>
+#include <linux/jhash.h>
+#include <linux/sort.h>
+
+#include "tracing_map.h"
+#include "trace.h"
+
+/**
+ * tracing_map_update_sum - Add a value to a tracing_map_elt's sum
+ * @elt: The tracing_map_elt
+ * @i: The index of the given sum associated with the tracing_map_elt
+ * @n: The value to add to the sum
+ *
+ * Add n to sum i associated with the specified tracing_map_elt
+ * instance. The index i is the index returned by the call to
+ * tracing_map_add_sum_field() when the tracing map was set up.
+ */
+void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n)
+{
+ atomic64_add(n, &elt->fields[i].sum);
+}
+
+/**
+ * tracing_map_read_sum - Return the value of a tracing_map_elt's sum
+ * @elt: The tracing_map_elt
+ * @i: The index of the given sum associated with the tracing_map_elt
+ *
+ * Retrieve the value of the sum i associated with the specified
+ * tracing_map_elt instance. The index i is the index returned by the
+ * call to tracing_map_add_sum_field() when the tracing map was set
+ * up.
+ *
+ * Return: The sum associated with field i for elt.
+ */
+u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i)
+{
+ return (u64)atomic64_read(&elt->fields[i].sum);
+}
+
+int tracing_map_cmp_string(void *val_a, void *val_b)
+{
+ char *a = val_a;
+ char *b = val_b;
+
+ return strcmp(a, b);
+}
+
+int tracing_map_cmp_none(void *val_a, void *val_b)
+{
+ return 0;
+}
+
+static int tracing_map_cmp_atomic64(void *val_a, void *val_b)
+{
+ u64 a = atomic64_read((atomic64_t *)val_a);
+ u64 b = atomic64_read((atomic64_t *)val_b);
+
+ return (a > b) ? 1 : ((a < b) ? -1 : 0);
+}
+
+#define DEFINE_TRACING_MAP_CMP_FN(type) \
+static int tracing_map_cmp_##type(void *val_a, void *val_b) \
+{ \
+ type a = *(type *)val_a; \
+ type b = *(type *)val_b; \
+ \
+ return (a > b) ? 1 : ((a < b) ? -1 : 0); \
+}
+
+DEFINE_TRACING_MAP_CMP_FN(s64);
+DEFINE_TRACING_MAP_CMP_FN(u64);
+DEFINE_TRACING_MAP_CMP_FN(s32);
+DEFINE_TRACING_MAP_CMP_FN(u32);
+DEFINE_TRACING_MAP_CMP_FN(s16);
+DEFINE_TRACING_MAP_CMP_FN(u16);
+DEFINE_TRACING_MAP_CMP_FN(s8);
+DEFINE_TRACING_MAP_CMP_FN(u8);
+
+tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size,
+ int field_is_signed)
+{
+ tracing_map_cmp_fn_t fn = tracing_map_cmp_none;
+
+ switch (field_size) {
+ case 8:
+ if (field_is_signed)
+ fn = tracing_map_cmp_s64;
+ else
+ fn = tracing_map_cmp_u64;
+ break;
+ case 4:
+ if (field_is_signed)
+ fn = tracing_map_cmp_s32;
+ else
+ fn = tracing_map_cmp_u32;
+ break;
+ case 2:
+ if (field_is_signed)
+ fn = tracing_map_cmp_s16;
+ else
+ fn = tracing_map_cmp_u16;
+ break;
+ case 1:
+ if (field_is_signed)
+ fn = tracing_map_cmp_s8;
+ else
+ fn = tracing_map_cmp_u8;
+ break;
+ }
+
+ return fn;
+}
+
+static int tracing_map_add_field(struct tracing_map *map,
+ tracing_map_cmp_fn_t cmp_fn)
+{
+ int ret = -EINVAL;
+
+ if (map->n_fields < TRACING_MAP_FIELDS_MAX) {
+ ret = map->n_fields;
+ map->fields[map->n_fields++].cmp_fn = cmp_fn;
+ }
+
+ return ret;
+}
+
+/**
+ * tracing_map_add_sum_field - Add a field describing a tracing_map sum
+ * @map: The tracing_map
+ *
+ * Add a sum field to the key and return the index identifying it in
+ * the map and associated tracing_map_elts. This is the index used
+ * for instance to update a sum for a particular tracing_map_elt using
+ * tracing_map_update_sum() or reading it via tracing_map_read_sum().
+ *
+ * Return: The index identifying the field in the map and associated
+ * tracing_map_elts.
+ */
+int tracing_map_add_sum_field(struct tracing_map *map)
+{
+ return tracing_map_add_field(map, tracing_map_cmp_atomic64);
+}
+
+/**
+ * tracing_map_add_key_field - Add a field describing the tracing_map key
+ * @map: The tracing_map
+ * @offset: The offset within the key
+ * @cmp_fn: The comparison function that will be used to sort on the key
+ *
+ * Let the map know there is a key and that if it's used as a sort key
+ * to use cmp_fn.
+ *
+ * Return: The index identifying the field in the map and associated
+ * tracing_map_elts.
+ */
+int tracing_map_add_key_field(struct tracing_map *map,
+ unsigned int offset,
+ tracing_map_cmp_fn_t cmp_fn)
+
+{
+ int idx = tracing_map_add_field(map, cmp_fn);
+
+ if (idx < 0)
+ return idx;
+
+ map->fields[idx].offset = offset;
+
+ map->key_idx[map->n_keys++] = idx;
+
+ return idx;
+}
+
+static void tracing_map_elt_clear(struct tracing_map_elt *elt)
+{
+ unsigned i;
+
+ for (i = 0; i < elt->map->n_fields; i++)
+ if (elt->fields[i].cmp_fn == tracing_map_cmp_atomic64)
+ atomic64_set(&elt->fields[i].sum, 0);
+
+ if (elt->map->ops && elt->map->ops->elt_clear)
+ elt->map->ops->elt_clear(elt);
+}
+
+static void tracing_map_elt_init_fields(struct tracing_map_elt *elt)
+{
+ unsigned int i;
+
+ tracing_map_elt_clear(elt);
+
+ for (i = 0; i < elt->map->n_fields; i++) {
+ elt->fields[i].cmp_fn = elt->map->fields[i].cmp_fn;
+
+ if (elt->fields[i].cmp_fn != tracing_map_cmp_atomic64)
+ elt->fields[i].offset = elt->map->fields[i].offset;
+ }
+}
+
+static void tracing_map_elt_free(struct tracing_map_elt *elt)
+{
+ if (!elt)
+ return;
+
+ if (elt->map->ops && elt->map->ops->elt_free)
+ elt->map->ops->elt_free(elt);
+ kfree(elt->fields);
+ kfree(elt->key);
+ kfree(elt);
+}
+
+static struct tracing_map_elt *tracing_map_elt_alloc(struct tracing_map *map)
+{
+ struct tracing_map_elt *elt;
+ int err = 0;
+
+ elt = kzalloc(sizeof(*elt), GFP_KERNEL);
+ if (!elt)
+ return ERR_PTR(-ENOMEM);
+
+ elt->map = map;
+
+ elt->key = kzalloc(map->key_size, GFP_KERNEL);
+ if (!elt->key) {
+ err = -ENOMEM;
+ goto free;
+ }
+
+ elt->fields = kcalloc(map->n_fields, sizeof(*elt->fields), GFP_KERNEL);
+ if (!elt->fields) {
+ err = -ENOMEM;
+ goto free;
+ }
+
+ tracing_map_elt_init_fields(elt);
+
+ if (map->ops && map->ops->elt_alloc) {
+ err = map->ops->elt_alloc(elt);
+ if (err)
+ goto free;
+ }
+ return elt;
+ free:
+ tracing_map_elt_free(elt);
+
+ return ERR_PTR(err);
+}
+
+static struct tracing_map_elt *get_free_elt(struct tracing_map *map)
+{
+ struct tracing_map_elt *elt = NULL;
+ int idx;
+
+ idx = atomic_inc_return(&map->next_elt);
+ if (idx < map->max_elts) {
+ elt = map->elts[idx];
+ if (map->ops && map->ops->elt_init)
+ map->ops->elt_init(elt);
+ }
+
+ return elt;
+}
+
+static void tracing_map_free_elts(struct tracing_map *map)
+{
+ unsigned int i;
+
+ if (!map->elts)
+ return;
+
+ for (i = 0; i < map->max_elts; i++)
+ tracing_map_elt_free(map->elts[i]);
+
+ kfree(map->elts);
+}
+
+static int tracing_map_alloc_elts(struct tracing_map *map)
+{
+ unsigned int i;
+
+ map->elts = kcalloc(map->max_elts, sizeof(struct tracing_map_elt *),
+ GFP_KERNEL);
+ if (!map->elts)
+ return -ENOMEM;
+
+ for (i = 0; i < map->max_elts; i++) {
+ map->elts[i] = tracing_map_elt_alloc(map);
+ if (!map->elts[i]) {
+ tracing_map_free_elts(map);
+
+ return -ENOMEM;
+ }
+ }
+
+ return 0;
+}
+
+static inline bool keys_match(void *key, void *test_key, unsigned key_size)
+{
+ bool match = true;
+
+ if (memcmp(key, test_key, key_size))
+ match = false;
+
+ return match;
+}
+
+/**
+ * tracing_map_insert - Insert key and/or return associated val
+ * @map: The tracing_map to insert into
+ * @key: The key to insert
+ *
+ * Inserts a key into the map and creates and returns a new
+ * tracing_map_elt for it, or if the key has already been inserted by
+ * a previous call, returns the tracing_map_elt already associated
+ * with it. When the map was created, the number of elements to be
+ * allocated for the map was specified, and that number of
+ * tracing_map_elts was created by tracing_map_init(). This is the
+ * pre-allocated pool of tracing map element that tracing_map_insert()
+ * will allocate from when adding new keys. Once that pool is
+ * exhausted, tracing_map_insert() is useless and will return NULL to
+ * signal that state.
+ *
+ * This is a lock-free tracing map insertion function implementing a
+ * modified form of Cliff Click's basic insertion algorithm. It
+ * requires the table size to be a power of two. To prevent any
+ * possibility of an infinite loop we always make the actual table
+ * size double the size of the requested table size (max_size * 2).
+ * Likewise, we never reuse a slot or resize or delete elements - when
+ * we've reached map_size entries, we simply return NULL once we've
+ * run out of entries. Readers can at any point in time traverse the
+ * tracing map and safely access the key/val pairs.
+ *
+ * Return: the tracing_map_elt * val associated with the key. If this
+ * was a newly inserted key, the val will be a newly allocated and
+ * associated tracing_map_elt * val. If the key wasn't found and the
+ * pool of tracing_map_elts has been exhausted, NULL is returned and
+ * no further insertions will succeed.
+ */
+struct tracing_map_elt *tracing_map_insert(struct tracing_map *map, void *key)
+{
+ u32 idx, key_hash, test_key;
+
+ key_hash = jhash(key, map->key_size, 0);
+ idx = key_hash >> (32 - (map->map_bits + 1));
+
+ while (1) {
+ idx &= (map->map_size - 1);
+ test_key = map->map[idx].key;
+
+ if (test_key && test_key == key_hash && map->map[idx].val &&
+ keys_match(key, map->map[idx].val->key, map->key_size))
+ return map->map[idx].val;
+
+ if (!test_key && !cmpxchg(&map->map[idx].key, 0, key_hash)) {
+ struct tracing_map_elt *elt;
+
+ elt = get_free_elt(map);
+ if (!elt)
+ break;
+ memcpy(elt->key, key, map->key_size);
+ map->map[idx].val = elt;
+
+ return map->map[idx].val;
+ }
+ idx++;
+ }
+
+ return NULL;
+}
+
+/**
+ * tracing_map_destroy - Destroy a tracing_map
+ * @map: The tracing_map to destroy
+ *
+ * Frees a tracing_map along with its associated array of
+ * tracing_map_elts.
+ *
+ * Callers should make sure there are no readers or writers actively
+ * reading or inserting into the map before calling this.
+ */
+void tracing_map_destroy(struct tracing_map *map)
+{
+ if (!map)
+ return;
+
+ tracing_map_free_elts(map);
+
+ kfree(map->map);
+ kfree(map);
+}
+
+/**
+ * tracing_map_clear - Clear a tracing_map
+ * @map: The tracing_map to clear
+ *
+ * Resets the tracing map to a cleared or initial state. The
+ * tracing_map_elts are all cleared, and the array of
+ * tracing_map_entries are reset to an initialized state.
+ *
+ * Callers should make sure there are no writers actively inserting
+ * into the map before calling this.
+ */
+void tracing_map_clear(struct tracing_map *map)
+{
+ unsigned int i, size;
+
+ atomic_set(&map->next_elt, -1);
+
+ size = map->map_size * sizeof(struct tracing_map_entry);
+ memset(map->map, 0, size);
+
+ for (i = 0; i < map->max_elts; i++)
+ tracing_map_elt_clear(map->elts[i]);
+}
+
+static void set_sort_key(struct tracing_map *map,
+ struct tracing_map_sort_key *sort_key)
+{
+ map->sort_key = *sort_key;
+}
+
+/**
+ * tracing_map_create - Create a lock-free map and element pool
+ * @map_bits: The size of the map (2 ** map_bits)
+ * @key_size: The size of the key for the map in bytes
+ * @ops: Optional client-defined tracing_map_ops instance
+ * @private_data: Client data associated with the map
+ *
+ * Creates and sets up a map to contain a max_size number of entries
+ * equal to a size of 2 ** map_bits. Before using, the map fields
+ * should be added to the map with tracing_map_add_sum_field() and
+ * tracing_map_add_key_field(). tracing_map_init() should then be
+ * called to allocate the array of tracing_map_elts, in order to avoid
+ * allocating anything in the map insertion path. The user-specified
+ * map_size reflect the max number of entries requested by the user -
+ * internally we double that in order to keep the table sparse and
+ * keep collisions manageable.
+ *
+ * A tracing_map is a special-purpose map designed to aggregate or
+ * 'sum' one or more values associated with a specific object of type
+ * tracing_map_elt, which is attached by the map to a given key.
+ *
+ * tracing_map_create() sets up the map itself, and provides
+ * operations for inserting tracing_map_elts, but doesn't allocate the
+ * tracing_map_elts themselves, or provide a means for describing the
+ * keys or sums associated with the tracing_map_elts. All
+ * tracing_map_elts for a given map have the same set of sums and
+ * keys, which are defined by the client using the functions
+ * tracing_map_add_key_field() and tracing_map_add_sum_field().
+ * Currently a tracing map can only have one key field i.e. compound
+ * keys aren't yet supported. Once the fields are defined, the pool
+ * of elements allocated for the map can be created, which occurs when
+ * the client code calls tracing_map_init().
+ *
+ * When tracing_map_init() returns, tracing_map_elt elements can be
+ * inserted into the map using tracing_map_insert(). When called,
+ * tracing_map_insert() grabs a free tracing_map_elt from the pool, or
+ * finds an existing match in the map and in either case returns it.
+ * The client can then use tracing_map_update_sum() and
+ * tracing_map_read_sum() to update or read a given sum field for the
+ * tracing_map_elt.
+ *
+ * The client can at any point retrieve and traverse the map and
+ * the set of inserted tracing_map_elts via tracing_map_sort_entries().
+ * Sorting can be done on any field, including the key.
+ *
+ * See tracing_map.h for a description of tracing_map_ops.
+ *
+ * Return: the tracing_map * if successful, ERR_PTR if not.
+ */
+struct tracing_map *tracing_map_create(unsigned int map_bits,
+ unsigned int key_size,
+ struct tracing_map_ops *ops,
+ void *private_data)
+{
+ struct tracing_map *map;
+ unsigned int i;
+
+ if (map_bits < TRACING_MAP_BITS_MIN ||
+ map_bits > TRACING_MAP_BITS_MAX)
+ return ERR_PTR(-EINVAL);
+
+ map = kzalloc(sizeof(*map), GFP_KERNEL);
+ if (!map)
+ return ERR_PTR(-ENOMEM);
+
+ map->map_bits = map_bits;
+ map->max_elts = (1 << map_bits);
+ atomic_set(&map->next_elt, -1);
+
+ map->map_size = (1 << (map_bits + 1));
+ map->ops = ops;
+
+ map->private_data = private_data;
+
+ map->map = kcalloc(map->map_size, sizeof(struct tracing_map_entry),
+ GFP_KERNEL);
+ if (!map->map)
+ goto free;
+
+ map->key_size = key_size;
+ for (i = 0; i < TRACING_MAP_KEYS_MAX; i++)
+ map->key_idx[i] = -1;
+ out:
+ return map;
+ free:
+ tracing_map_destroy(map);
+ map = ERR_PTR(-ENOMEM);
+
+ goto out;
+}
+
+/**
+ * tracing_map_init - Allocate and clear a map's tracing_map_elts
+ * @map: The tracing_map to initialize
+ *
+ * Creates and sets up a map to contain a max_size number of entries
+ * equal to a size of 2 ** map_bits. Before using, the map fields
+ * should be added to the map with tracing_map_add_key_field() and
+ * tracing_map_add_key_field(). tracing_map_init() should then be
+ * called to allocate the array of tracing_map_elts, in order to avoid
+ * allocating anything in the map insertion path. The user-specified
+ * map_size reflect the max number of entries requested by the user -
+ * internally we double that in order to keep the table sparse and
+ * keep collisions manageable.
+ *
+ * See tracing_map.h for a description of tracing_map_ops.
+ *
+ * Return: the tracing_map * if successful, ERR_PTR if not.
+ */
+int tracing_map_init(struct tracing_map *map)
+{
+ int err;
+
+ if (map->n_fields < 2)
+ return -EINVAL; /* need at least 1 key and 1 val */
+
+ err = tracing_map_alloc_elts(map);
+ if (err)
+ return err;
+
+ tracing_map_clear(map);
+
+ return err;
+}
+
+static int cmp_entries_dup(const struct tracing_map_sort_entry **a,
+ const struct tracing_map_sort_entry **b)
+{
+ int ret = 0;
+
+ if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size))
+ ret = 1;
+
+ return ret;
+}
+
+static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
+ const struct tracing_map_sort_entry **b)
+{
+ const struct tracing_map_elt *elt_a, *elt_b;
+ struct tracing_map_sort_key *sort_key;
+ struct tracing_map_field *field;
+ tracing_map_cmp_fn_t cmp_fn;
+ void *val_a, *val_b;
+ int ret = 0;
+
+ elt_a = (*a)->elt;
+ elt_b = (*b)->elt;
+
+ sort_key = &elt_a->map->sort_key;
+
+ field = &elt_a->fields[sort_key->field_idx];
+ cmp_fn = field->cmp_fn;
+
+ val_a = &elt_a->fields[sort_key->field_idx].sum;
+ val_b = &elt_b->fields[sort_key->field_idx].sum;
+
+ ret = cmp_fn(val_a, val_b);
+ if (sort_key->descending)
+ ret = -ret;
+
+ return ret;
+}
+
+static int cmp_entries_key(const struct tracing_map_sort_entry **a,
+ const struct tracing_map_sort_entry **b)
+{
+ const struct tracing_map_elt *elt_a, *elt_b;
+ struct tracing_map_sort_key *sort_key;
+ struct tracing_map_field *field;
+ tracing_map_cmp_fn_t cmp_fn;
+ void *val_a, *val_b;
+ int ret = 0;
+
+ elt_a = (*a)->elt;
+ elt_b = (*b)->elt;
+
+ sort_key = &elt_a->map->sort_key;
+
+ field = &elt_a->fields[sort_key->field_idx];
+
+ cmp_fn = field->cmp_fn;
+
+ val_a = elt_a->key + field->offset;
+ val_b = elt_b->key + field->offset;
+
+ ret = cmp_fn(val_a, val_b);
+ if (sort_key->descending)
+ ret = -ret;
+
+ return ret;
+}
+
+static void destroy_sort_entry(struct tracing_map_sort_entry *entry)
+{
+ if (!entry)
+ return;
+
+ if (entry->elt_copied)
+ tracing_map_elt_free(entry->elt);
+
+ kfree(entry);
+}
+
+/**
+ * tracing_map_destroy_entries - Destroy a tracing_map_sort_entries() array
+ * @entries: The entries to destroy
+ * @n_entries: The number of entries in the array
+ *
+ * Destroy the elements returned by a tracing_map_sort_entries() call.
+ */
+void tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries,
+ unsigned int n_entries)
+{
+ unsigned int i;
+
+ for (i = 0; i < n_entries; i++)
+ destroy_sort_entry(entries[i]);
+}
+
+static struct tracing_map_sort_entry *
+create_sort_entry(void *key, struct tracing_map_elt *elt)
+{
+ struct tracing_map_sort_entry *sort_entry;
+
+ sort_entry = kzalloc(sizeof(*sort_entry), GFP_KERNEL);
+ if (!sort_entry)
+ return NULL;
+
+ sort_entry->key = key;
+ sort_entry->elt = elt;
+
+ return sort_entry;
+}
+
+static struct tracing_map_elt *copy_elt(struct tracing_map_elt *elt)
+{
+ struct tracing_map_elt *dup_elt;
+ unsigned int i;
+
+ dup_elt = tracing_map_elt_alloc(elt->map);
+ if (!dup_elt)
+ return NULL;
+
+ if (elt->map->ops && elt->map->ops->elt_copy)
+ elt->map->ops->elt_copy(dup_elt, elt);
+
+ dup_elt->private_data = elt->private_data;
+ memcpy(dup_elt->key, elt->key, elt->map->key_size);
+
+ for (i = 0; i < elt->map->n_fields; i++) {
+ atomic64_set(&dup_elt->fields[i].sum,
+ atomic64_read(&elt->fields[i].sum));
+ dup_elt->fields[i].cmp_fn = elt->fields[i].cmp_fn;
+ }
+
+ return dup_elt;
+}
+
+static int merge_dup(struct tracing_map_sort_entry **sort_entries,
+ unsigned int target, unsigned int dup)
+{
+ struct tracing_map_elt *target_elt, *elt;
+ bool first_dup = (target - dup) == 1;
+ int i;
+
+ if (first_dup) {
+ elt = sort_entries[target]->elt;
+ target_elt = copy_elt(elt);
+ if (!target_elt)
+ return -ENOMEM;
+ sort_entries[target]->elt = target_elt;
+ sort_entries[target]->elt_copied = true;
+ } else
+ target_elt = sort_entries[target]->elt;
+
+ elt = sort_entries[dup]->elt;
+
+ for (i = 0; i < elt->map->n_fields; i++)
+ atomic64_add(atomic64_read(&elt->fields[i].sum),
+ &target_elt->fields[i].sum);
+
+ sort_entries[dup]->dup = true;
+
+ return 0;
+}
+
+static int merge_dups(struct tracing_map_sort_entry **sort_entries,
+ int n_entries, unsigned int key_size)
+{
+ unsigned int dups = 0, total_dups = 0;
+ int err, i, j;
+ void *key;
+
+ if (n_entries < 2)
+ return total_dups;
+
+ sort(sort_entries, n_entries, sizeof(struct tracing_map_sort_entry *),
+ (int (*)(const void *, const void *))cmp_entries_dup, NULL);
+
+ key = sort_entries[0]->key;
+ for (i = 1; i < n_entries; i++) {
+ if (!memcmp(sort_entries[i]->key, key, key_size)) {
+ dups++; total_dups++;
+ err = merge_dup(sort_entries, i - dups, i);
+ if (err)
+ return err;
+ continue;
+ }
+ key = sort_entries[i]->key;
+ dups = 0;
+ }
+
+ if (!total_dups)
+ return total_dups;
+
+ for (i = 0, j = 0; i < n_entries; i++) {
+ if (!sort_entries[i]->dup) {
+ sort_entries[j] = sort_entries[i];
+ if (j++ != i)
+ sort_entries[i] = NULL;
+ } else {
+ destroy_sort_entry(sort_entries[i]);
+ sort_entries[i] = NULL;
+ }
+ }
+
+ return total_dups;
+}
+
+static bool is_key(struct tracing_map *map, unsigned int field_idx)
+{
+ unsigned int i;
+
+ for (i = 0; i < map->n_keys; i++)
+ if (map->key_idx[i] == field_idx)
+ return true;
+ return false;
+}
+
+static void sort_secondary(struct tracing_map *map,
+ const struct tracing_map_sort_entry **entries,
+ unsigned int n_entries,
+ struct tracing_map_sort_key *primary_key,
+ struct tracing_map_sort_key *secondary_key)
+{
+ int (*primary_fn)(const struct tracing_map_sort_entry **,
+ const struct tracing_map_sort_entry **);
+ int (*secondary_fn)(const struct tracing_map_sort_entry **,
+ const struct tracing_map_sort_entry **);
+ unsigned i, start = 0, n_sub = 1;
+
+ if (is_key(map, primary_key->field_idx))
+ primary_fn = cmp_entries_key;
+ else
+ primary_fn = cmp_entries_sum;
+
+ if (is_key(map, secondary_key->field_idx))
+ secondary_fn = cmp_entries_key;
+ else
+ secondary_fn = cmp_entries_sum;
+
+ for (i = 0; i < n_entries - 1; i++) {
+ const struct tracing_map_sort_entry **a = &entries[i];
+ const struct tracing_map_sort_entry **b = &entries[i + 1];
+
+ if (primary_fn(a, b) == 0) {
+ n_sub++;
+ if (i < n_entries - 2)
+ continue;
+ }
+
+ if (n_sub < 2) {
+ start = i + 1;
+ n_sub = 1;
+ continue;
+ }
+
+ set_sort_key(map, secondary_key);
+ sort(&entries[start], n_sub,
+ sizeof(struct tracing_map_sort_entry *),
+ (int (*)(const void *, const void *))secondary_fn, NULL);
+ set_sort_key(map, primary_key);
+
+ start = i + 1;
+ n_sub = 1;
+ }
+}
+
+/**
+ * tracing_map_sort_entries - Sort the current set of tracing_map_lts in a map
+ * @map: The tracing_map
+ * @sort_key: The sort key to use for sorting
+ * @sort_entries: outval: pointer to allocated and sorted array of entries
+ *
+ * tracing_map_sort_entries() sorts the current set of entries in the
+ * map and returns the list of tracing_map_sort_entries containing
+ * them to the client in the sort_entries param.
+ *
+ * The sort_key has only two fields: idx and descending. 'idx' refers
+ * to the index of the field added via tracing_map_add_sum_field() or
+ * tracing_map_add_key_field() when the tracing_map was initialized.
+ * 'descending' is a flag that if set reverses the sort order, which
+ * by default is ascending.
+ *
+ * The client should not hold on to the returned array but use it
+ * and call tracing_map_destroy_sort_entries() when done.
+ *
+ * Return: the number of sort_entries in the tracing_map_sort_entry
+ * array, negative on err
+ */
+int tracing_map_sort_entries(struct tracing_map *map,
+ struct tracing_map_sort_key *sort_keys,
+ unsigned int n_sort_keys,
+ struct tracing_map_sort_entry ***sort_entries)
+{
+ int (*cmp_entries_fn)(const struct tracing_map_sort_entry **,
+ const struct tracing_map_sort_entry **);
+ struct tracing_map_sort_entry *sort_entry, **entries;
+ int i, n_entries, ret;
+
+ entries = kcalloc(map->max_elts, sizeof(sort_entry), GFP_KERNEL);
+ if (!entries)
+ return -ENOMEM;
+
+ for (i = 0, n_entries = 0; i < map->map_size; i++) {
+ if (!map->map[i].key || !map->map[i].val)
+ continue;
+
+ entries[n_entries] = create_sort_entry(map->map[i].val->key,
+ map->map[i].val);
+ if (!entries[n_entries++]) {
+ ret = -ENOMEM;
+ goto free;
+ }
+ }
+
+ if (n_entries == 0) {
+ ret = 0;
+ goto free;
+ }
+
+ if (n_entries == 1) {
+ *sort_entries = entries;
+ return 1;
+ }
+
+ ret = merge_dups(entries, n_entries, map->key_size);
+ if (ret < 0)
+ goto free;
+ n_entries -= ret;
+
+ if (is_key(map, sort_keys[0].field_idx))
+ cmp_entries_fn = cmp_entries_key;
+ else
+ cmp_entries_fn = cmp_entries_sum;
+
+ set_sort_key(map, &sort_keys[0]);
+
+ sort(entries, n_entries, sizeof(struct tracing_map_sort_entry *),
+ (int (*)(const void *, const void *))cmp_entries_fn, NULL);
+
+ if (n_sort_keys > 1)
+ sort_secondary(map,
+ (const struct tracing_map_sort_entry **)entries,
+ n_entries,
+ &sort_keys[0],
+ &sort_keys[1]);
+
+ *sort_entries = entries;
+
+ return n_entries;
+ free:
+ tracing_map_destroy_sort_entries(entries, n_entries);
+
+ return ret;
+}
diff --git a/kernel/trace/tracing_map.h b/kernel/trace/tracing_map.h
new file mode 100644
index 0000000..826fb11
--- /dev/null
+++ b/kernel/trace/tracing_map.h
@@ -0,0 +1,143 @@
+#ifndef __TRACING_MAP_H
+#define __TRACING_MAP_H
+
+#define TRACING_MAP_BITS_DEFAULT 11
+#define TRACING_MAP_BITS_MAX 17
+#define TRACING_MAP_BITS_MIN 7
+
+#define TRACING_MAP_FIELDS_MAX 4
+#define TRACING_MAP_KEYS_MAX 2
+
+#define TRACING_MAP_SORT_KEYS_MAX 2
+
+typedef int (*tracing_map_cmp_fn_t) (void *val_a, void *val_b);
+
+struct tracing_map_field {
+ tracing_map_cmp_fn_t cmp_fn;
+ union {
+ atomic64_t sum;
+ unsigned int offset;
+ };
+};
+
+struct tracing_map_elt {
+ struct tracing_map *map;
+ struct tracing_map_field *fields;
+ void *key;
+ void *private_data;
+};
+
+struct tracing_map_entry {
+ u32 key;
+ struct tracing_map_elt *val;
+};
+
+struct tracing_map_sort_key {
+ unsigned int field_idx;
+ bool descending;
+};
+
+struct tracing_map_sort_entry {
+ void *key;
+ struct tracing_map_elt *elt;
+ bool elt_copied;
+ bool dup;
+};
+
+struct tracing_map {
+ unsigned int key_size;
+ unsigned int map_bits;
+ unsigned int map_size;
+ unsigned int max_elts;
+ atomic_t next_elt;
+ struct tracing_map_elt **elts;
+ struct tracing_map_entry *map;
+ struct tracing_map_ops *ops;
+ void *private_data;
+ struct tracing_map_field fields[TRACING_MAP_FIELDS_MAX];
+ unsigned int n_fields;
+ int key_idx[TRACING_MAP_KEYS_MAX];
+ unsigned int n_keys;
+ struct tracing_map_sort_key sort_key;
+};
+
+/**
+ * struct tracing_map_ops - callbacks for tracing_map
+ *
+ * The methods in this structure provide per-event trigger hooks for
+ * various trigger operations.
+ *
+ * All the methods below are optional.
+ *
+ * @elt_alloc: When a tracing_map_elt is allocated, this function, if
+ * defined, will be called and gives clients the opportunity to
+ * allocate additional data and attach it to the element
+ * (tracing_map_elt->private_data is meant for that purpose).
+ * Element allocation occurs before tracing begins, when the
+ * tracing_map_init() call is made by client code.
+ *
+ * @elt_copy: At certain points in the lifetime of an element, it may
+ * need to be copied. The copy should include a copy of the
+ * client-allocated data, which can be copied into the 'to'
+ * element from the 'from' element.
+ *
+ * @elt_free: When a tracing_map_element is freed, this function is
+ * called and allows client-allocated per-element data to be
+ * freed.
+ *
+ * @elt_clear: This callback allows per-element client-defined data to
+ * be cleared, if applicable.
+ *
+ * @elt_init: This callback allows per-element client-defined data to
+ * be initialized when used i.e. when the element is actually
+ * claimed by tracing_map_insert() in the context of the map
+ * insertion.
+ */
+struct tracing_map_ops {
+ int (*elt_alloc)(struct tracing_map_elt *elt);
+ void (*elt_copy)(struct tracing_map_elt *to,
+ struct tracing_map_elt *from);
+ void (*elt_free)(struct tracing_map_elt *elt);
+ void (*elt_clear)(struct tracing_map_elt *elt);
+ void (*elt_init)(struct tracing_map_elt *elt);
+};
+
+extern struct tracing_map *tracing_map_create(unsigned int map_bits,
+ unsigned int key_size,
+ struct tracing_map_ops *ops,
+ void *private_data);
+extern int tracing_map_init(struct tracing_map *map);
+
+extern int tracing_map_add_sum_field(struct tracing_map *map);
+extern int tracing_map_add_key_field(struct tracing_map *map,
+ unsigned int offset,
+ tracing_map_cmp_fn_t cmp_fn);
+
+extern void tracing_map_destroy(struct tracing_map *map);
+extern void tracing_map_clear(struct tracing_map *map);
+
+extern struct tracing_map_elt *
+tracing_map_insert(struct tracing_map *map, void *key);
+
+extern tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size,
+ int field_is_signed);
+extern int tracing_map_cmp_string(void *val_a, void *val_b);
+extern int tracing_map_cmp_none(void *val_a, void *val_b);
+
+extern void tracing_map_update_sum(struct tracing_map_elt *elt,
+ unsigned int i, u64 n);
+extern u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i);
+extern void tracing_map_set_field_descr(struct tracing_map *map,
+ unsigned int i,
+ unsigned int key_offset,
+ tracing_map_cmp_fn_t cmp_fn);
+extern int
+tracing_map_sort_entries(struct tracing_map *map,
+ struct tracing_map_sort_key *sort_keys,
+ unsigned int n_sort_keys,
+ struct tracing_map_sort_entry ***sort_entries);
+
+extern void
+tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries,
+ unsigned int n_entries);
+#endif /* __TRACING_MAP_H */
--
1.9.3
'hist' triggers allow users to continually aggregate trace events,
which can then be viewed afterwards by simply reading a 'hist' file
containing the aggregation in a human-readable format.
The basic idea is very simple and boils down to a mechanism whereby
trace events, rather than being exhaustively dumped in raw form and
viewed directly, are automatically 'compressed' into meaningful tables
completely defined by the user.
This is done strictly via single-line command-line commands and
without the aid of any kind of programming language or interpreter.
A surprising number of typical use cases can be accomplished by users
via this simple mechanism. In fact, a large number of the tasks that
users typically do using the more complicated script-based tracing
tools, at least during the initial stages of an investigation, can be
accomplished by simply specifying a set of keys and values to be used
in the creation of a hash table.
The Linux kernel trace event subsystem happens to provide an extensive
list of keys and values ready-made for such a purpose in the form of
the event format files associated with each trace event. By simply
consulting the format file for field names of interest and by plugging
them into the hist trigger command, users can create an endless number
of useful aggregations to help with investigating various properties
of the system. See Documentation/trace/events.txt for examples.
hist triggers are implemented on top of the existing event trigger
infrastructure, and as such are consistent with the existing triggers
from a user's perspective as well.
The basic syntax follows the existing trigger syntax. Users start an
aggregation by writing a 'hist' trigger to the event of interest's
trigger file:
# echo hist:keys=xxx:values=yyy [ if filter] > event/trigger
Once a hist trigger has been set up, by default it continually
aggregates every matching event into a hash table using the event key
and value fields specified.
To view the aggregation at any point in time, simply read the 'hist'
file in the same directory as the 'trigger' file:
# cat event/hist
The detailed syntax provides additional options for user control, and
is described exhaustively in Documentation/trace/events.txt and in the
virtual tracing/README file in the tracing subsystem.
Signed-off-by: Tom Zanussi <[email protected]>
fixes sort key parsing
Signed-off-by: Tom Zanussi <[email protected]>
Add sym-offset
And change sym, add more space for both. And make modifiers stricter.
Signed-off-by: Tom Zanussi <[email protected]>
---
include/linux/trace_events.h | 5 +-
kernel/trace/Kconfig | 14 +
kernel/trace/Makefile | 1 +
kernel/trace/trace.c | 55 ++
kernel/trace/trace.h | 21 +
kernel/trace/trace_events.c | 4 +
kernel/trace/trace_events_hist.c | 1292 +++++++++++++++++++++++++++++++++++
kernel/trace/trace_events_trigger.c | 29 +-
8 files changed, 1404 insertions(+), 17 deletions(-)
create mode 100644 kernel/trace/trace_events_hist.c
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index d70c0d2..0faf48b 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -410,6 +410,7 @@ enum event_trigger_type {
ETT_SNAPSHOT = (1 << 1),
ETT_STACKTRACE = (1 << 2),
ETT_EVENT_ENABLE = (1 << 3),
+ ETT_EVENT_HIST = (1 << 4),
};
extern int filter_match_preds(struct event_filter *filter, void *rec);
@@ -507,7 +508,7 @@ event_trigger_unlock_commit(struct trace_event_file *file,
trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
if (tt)
- event_triggers_post_call(file, tt);
+ event_triggers_post_call(file, tt, entry);
}
/**
@@ -540,7 +541,7 @@ event_trigger_unlock_commit_regs(struct trace_event_file *file,
irq_flags, pc, regs);
if (tt)
- event_triggers_post_call(file, tt);
+ event_triggers_post_call(file, tt, entry);
}
#ifdef CONFIG_BPF_SYSCALL
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 3b9a48a..85f8025 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -528,6 +528,20 @@ config MMIOTRACE
See Documentation/trace/mmiotrace.txt.
If you are not helping to develop drivers, say N.
+config HIST_TRIGGERS
+ bool "Histogram triggers"
+ depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
+ help
+ Hist triggers allow one or more arbitrary trace event fields
+ to be aggregated into hash tables and dumped to stdout by
+ reading a debugfs/tracefs file. They're useful for
+ gathering quick and dirty (though precise) summaries of
+ event activity as an initial guide for further investigation
+ using more advanced tools.
+
+ See Documentation/trace/events.txt.
+ If in doubt, say N.
+
config MMIOTRACE_TEST
tristate "Test module for mmiotrace"
depends on MMIOTRACE && m
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 3b26cfb..7faace3 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_EVENT_TRACING) += trace_event_perf.o
endif
obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o
+obj-$(CONFIG_HIST_TRIGGERS) += trace_events_hist.o
obj-$(CONFIG_BPF_EVENTS) += bpf_trace.o
obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o
obj-$(CONFIG_TRACEPOINTS) += power-traces.o
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index abcbf7f..c37c2d5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3767,6 +3767,9 @@ static const char readme_msg[] =
#ifdef CONFIG_TRACER_SNAPSHOT
"\t\t snapshot\n"
#endif
+#ifdef CONFIG_HIST_TRIGGERS
+ "\t\t hist (see below)\n"
+#endif
"\t example: echo traceoff > events/block/block_unplug/trigger\n"
"\t echo traceoff:3 > events/block/block_unplug/trigger\n"
"\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
@@ -3782,6 +3785,58 @@ static const char readme_msg[] =
"\t To remove a trigger with a count:\n"
"\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
"\t Filters can be ignored when removing a trigger.\n"
+#ifdef CONFIG_HIST_TRIGGERS
+ " hist trigger\t- If set, event hits are aggregated into a hash table\n"
+ "\t Format: hist:keys=<field1>[,field2,...]\n"
+ "\t [:values=<field1[,field2,...]]\n"
+ "\t [:sort=field1,field2,...]\n"
+ "\t [:size=#entries]\n"
+ "\t [:pause][:continue][:clear]\n"
+ "\t [if <filter>]\n\n"
+ "\t When a matching event is hit, an entry is added to a hash\n"
+ "\t table using the key(s) and value(s) named. Keys and values\n"
+ "\t correspond to fields in the event's format description.\n"
+ "\t Values must correspond to numeric fields - on an event hit,\n"
+ "\t the value(s) will be added to a sum kept for that field.\n"
+ "\t The special string 'hitcount' can be used in place of an\n"
+ "\t explicit value field - this is simply a count of event hits.\n"
+ "\t If 'values' is not specified, 'hitcount' will be assumed.\n"
+ "\t Keys can be any field, or the special string 'stacktrace',\n"
+ "\t which will use the event's kernel stacktrace as the key.\n"
+ "\t Compound keys consisting of up to two fields can be specified\n"
+ "\t by the 'keys' keyword. Additionally, sort keys consisting\n"
+ "\t of up to two fields can be specified by the 'sort' keyword.\n\n"
+ "\t Reading the 'hist' file for the event will dump the hash\n"
+ "\t table in its entirety to stdout. Each printed hash table\n"
+ "\t entry is a simple list of the keys and values comprising the\n"
+ "\t entry; keys are printed first and are delineated by curly\n"
+ "\t braces, and are followed by the set of value fields for the\n"
+ "\t entry. By default, numeric fields are displayed as base-10\n"
+ "\t integers. This can be modified by appending any of the\n"
+ "\t following modifiers to the field name:\n\n"
+ "\t .hex display a number as a hex value\n"
+ "\t .sym display an address as a symbol\n"
+ "\t .sym-offset display an address as a symbol and offset\n"
+ "\t .syscall display a syscall id as a syscall name\n"
+ "\t .execname display a common_pid as a program name\n\n"
+ "\t By default, the size of the hash table is 2048 entries. The\n"
+ "\t 'size' param can be used to specify more or fewer than that.\n"
+ "\t The units are in terms of hashtable entries - if a run uses\n"
+ "\t more entries than specified, the results will show the number\n"
+ "\t of 'drops', the number of hits that were ignored. The size\n"
+ "\t should be a power of 2 between 128 and 131072 (any non-\n"
+ "\t power-of-2 number specified will be rounded up).\n\n"
+ "\t The 'sort' param can be used to specify a value field to sort\n"
+ "\t on. The default if unspecified is 'hitcount' and the.\n"
+ "\t default sort order is 'ascending'. To sort in the opposite\n"
+ "\t direction, append .descending' to the sort key.\n\n"
+ "\t The 'pause' param can be used to pause an existing hist\n"
+ "\t trigger or to start a hist trigger but not log any events\n"
+ "\t until told to do so. 'continue' can be used to start or\n"
+ "\t restart a paused hist trigger.\n\n"
+ "\t The 'clear' param will clear the contents of a running hist\n"
+ "\t trigger and leave its current paused/active state.\n\n"
+#endif
;
static ssize_t
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8dcb77c..e6cb781 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1098,6 +1098,13 @@ extern struct mutex event_mutex;
extern struct list_head ftrace_events;
extern const struct file_operations event_trigger_fops;
+extern const struct file_operations event_hist_fops;
+
+#ifdef CONFIG_HIST_TRIGGERS
+extern int register_trigger_hist_cmd(void);
+#else
+static inline int register_trigger_hist_cmd(void) { return 0; }
+#endif
extern int register_trigger_cmds(void);
extern void clear_event_triggers(struct trace_array *tr);
@@ -1114,6 +1121,20 @@ struct event_trigger_data {
struct list_head list;
};
+extern void trigger_data_free(struct event_trigger_data *data);
+extern int event_trigger_init(struct event_trigger_ops *ops,
+ struct event_trigger_data *data);
+extern int trace_event_trigger_enable_disable(struct trace_event_file *file,
+ int trigger_enable);
+extern void update_cond_flag(struct trace_event_file *file);
+extern void unregister_trigger(char *glob, struct event_trigger_ops *ops,
+ struct event_trigger_data *test,
+ struct trace_event_file *file);
+extern int set_trigger_filter(char *filter_str,
+ struct event_trigger_data *trigger_data,
+ struct trace_event_file *file);
+extern int register_event_command(struct event_command *cmd);
+
/**
* struct event_trigger_ops - callbacks for trace event triggers
*
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 404a372..2bf0465 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1628,6 +1628,10 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
trace_create_file("trigger", 0644, file->dir, file,
&event_trigger_fops);
+#ifdef CONFIG_HIST_TRIGGERS
+ trace_create_file("hist", 0444, file->dir, file,
+ &event_hist_fops);
+#endif
trace_create_file("format", 0444, file->dir, call,
&ftrace_event_format_fops);
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
new file mode 100644
index 0000000..e005683
--- /dev/null
+++ b/kernel/trace/trace_events_hist.c
@@ -0,0 +1,1292 @@
+/*
+ * trace_events_hist - trace event hist triggers
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2015 Tom Zanussi <[email protected]>
+ */
+
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+
+#include "tracing_map.h"
+#include "trace.h"
+
+struct hist_field;
+
+typedef u64 (*hist_field_fn_t) (struct hist_field *field, void *event);
+
+struct hist_field {
+ struct ftrace_event_field *field;
+ unsigned long flags;
+ hist_field_fn_t fn;
+ unsigned int size;
+ unsigned int offset;
+};
+
+static u64 hist_field_none(struct hist_field *field, void *event)
+{
+ return 0;
+}
+
+static u64 hist_field_counter(struct hist_field *field, void *event)
+{
+ return 1;
+}
+
+static u64 hist_field_string(struct hist_field *hist_field, void *event)
+{
+ char *addr = (char *)(event + hist_field->field->offset);
+
+ return (u64)addr;
+}
+
+#define DEFINE_HIST_FIELD_FN(type) \
+static u64 hist_field_##type(struct hist_field *hist_field, void *event)\
+{ \
+ type *addr = (type *)(event + hist_field->field->offset); \
+ \
+ return (u64)*addr; \
+}
+
+DEFINE_HIST_FIELD_FN(s64);
+DEFINE_HIST_FIELD_FN(u64);
+DEFINE_HIST_FIELD_FN(s32);
+DEFINE_HIST_FIELD_FN(u32);
+DEFINE_HIST_FIELD_FN(s16);
+DEFINE_HIST_FIELD_FN(u16);
+DEFINE_HIST_FIELD_FN(s8);
+DEFINE_HIST_FIELD_FN(u8);
+
+#define HITCOUNT_IDX 0
+#define HIST_KEY_MAX 2
+#define HIST_KEY_SIZE_MAX 128
+
+enum hist_field_flags {
+ HIST_FIELD_HITCOUNT = 1,
+ HIST_FIELD_KEY = 2,
+ HIST_FIELD_SYM = 4,
+ HIST_FIELD_SYM_OFFSET = 8,
+ HIST_FIELD_HEX = 16,
+ HIST_FIELD_STACKTRACE = 32,
+ HIST_FIELD_STRING = 64,
+ HIST_FIELD_EXECNAME = 128,
+ HIST_FIELD_SYSCALL = 256,
+};
+
+struct hist_trigger_attrs {
+ char *keys_str;
+ char *vals_str;
+ char *sort_key_str;
+ bool pause;
+ bool cont;
+ bool clear;
+ unsigned int map_bits;
+};
+
+struct hist_trigger_data {
+ atomic64_t total_hits;
+ struct hist_field *fields[TRACING_MAP_FIELDS_MAX];
+ unsigned int n_vals;
+ unsigned int n_keys;
+ unsigned int n_fields;
+ unsigned int key_size;
+ struct tracing_map_sort_key sort_keys[TRACING_MAP_SORT_KEYS_MAX];
+ unsigned int n_sort_keys;
+ struct trace_event_file *event_file;
+ atomic64_t drops;
+ struct hist_trigger_attrs *attrs;
+ struct tracing_map *map;
+};
+
+#define HIST_STACKTRACE_DEPTH 16
+#define HIST_STACKTRACE_SKIP 5
+
+static hist_field_fn_t select_value_fn(int field_size, int field_is_signed)
+{
+ hist_field_fn_t fn = NULL;
+
+ switch (field_size) {
+ case 8:
+ if (field_is_signed)
+ fn = hist_field_s64;
+ else
+ fn = hist_field_u64;
+ break;
+ case 4:
+ if (field_is_signed)
+ fn = hist_field_s32;
+ else
+ fn = hist_field_u32;
+ break;
+ case 2:
+ if (field_is_signed)
+ fn = hist_field_s16;
+ else
+ fn = hist_field_u16;
+ break;
+ case 1:
+ if (field_is_signed)
+ fn = hist_field_s8;
+ else
+ fn = hist_field_u8;
+ break;
+ }
+
+ return fn;
+}
+
+static int parse_map_size(char *str)
+{
+ unsigned long size, map_bits;
+ int ret;
+
+ strsep(&str, "=");
+ if (!str) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = kstrtoul(str, 0, &size);
+ if (ret)
+ goto out;
+
+ map_bits = ilog2(roundup_pow_of_two(size));
+ if (map_bits < TRACING_MAP_BITS_MIN ||
+ map_bits > TRACING_MAP_BITS_MAX)
+ ret = -EINVAL;
+ else
+ ret = map_bits;
+ out:
+ return ret;
+}
+
+static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
+{
+ kfree(attrs->sort_key_str);
+ kfree(attrs->keys_str);
+ kfree(attrs->vals_str);
+ kfree(attrs);
+}
+
+static struct hist_trigger_attrs *parse_hist_trigger_attrs(char *trigger_str)
+{
+ struct hist_trigger_attrs *attrs;
+ int ret = 0;
+
+ attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
+ if (!attrs)
+ return ERR_PTR(-ENOMEM);
+
+ while (trigger_str) {
+ char *str = strsep(&trigger_str, ":");
+
+ if (!strncmp(str, "keys", strlen("keys")) ||
+ !strncmp(str, "key", strlen("key")))
+ attrs->keys_str = kstrdup(str, GFP_KERNEL);
+ else if (!strncmp(str, "values", strlen("values")) ||
+ !strncmp(str, "vals", strlen("vals")) ||
+ !strncmp(str, "val", strlen("val")))
+ attrs->vals_str = kstrdup(str, GFP_KERNEL);
+ else if (!strncmp(str, "sort", strlen("sort")))
+ attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
+ else if (!strncmp(str, "pause", strlen("pause")))
+ attrs->pause = true;
+ else if (!strncmp(str, "continue", strlen("continue")) ||
+ !strncmp(str, "cont", strlen("cont")))
+ attrs->cont = true;
+ else if (!strncmp(str, "clear", strlen("clear")))
+ attrs->clear = true;
+ else if (!strncmp(str, "size", strlen("size"))) {
+ int map_bits = parse_map_size(str);
+
+ if (map_bits < 0) {
+ ret = map_bits;
+ goto free;
+ }
+ attrs->map_bits = map_bits;
+ } else {
+ ret = -EINVAL;
+ goto free;
+ }
+ }
+
+ return attrs;
+ free:
+ destroy_hist_trigger_attrs(attrs);
+
+ return ERR_PTR(ret);
+}
+
+static inline void save_comm(char *comm, struct task_struct *task)
+{
+ if (!task->pid) {
+ strcpy(comm, "<idle>");
+ return;
+ }
+
+ if (WARN_ON_ONCE(task->pid < 0)) {
+ strcpy(comm, "<XXX>");
+ return;
+ }
+
+ if (task->pid > PID_MAX_DEFAULT) {
+ strcpy(comm, "<...>");
+ return;
+ }
+
+ memcpy(comm, task->comm, TASK_COMM_LEN);
+}
+
+static void hist_trigger_elt_free(struct tracing_map_elt *elt)
+{
+ kfree((char *)elt->private_data);
+}
+
+static int hist_trigger_elt_alloc(struct tracing_map_elt *elt)
+{
+ struct hist_trigger_data *hist_data = elt->map->private_data;
+ struct hist_field *key_field;
+ unsigned int i;
+
+ for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
+ key_field = hist_data->fields[i];
+
+ if (key_field->flags & HIST_FIELD_EXECNAME) {
+ unsigned int size = TASK_COMM_LEN + 1;
+
+ elt->private_data = kzalloc(size, GFP_KERNEL);
+ if (!elt->private_data)
+ return -ENOMEM;
+ break;
+ }
+ }
+
+ return 0;
+}
+
+static void hist_trigger_elt_copy(struct tracing_map_elt *to,
+ struct tracing_map_elt *from)
+{
+ char *comm_from = from->private_data;
+ char *comm_to = to->private_data;
+
+ if (comm_from)
+ memcpy(comm_to, comm_from, TASK_COMM_LEN + 1);
+}
+
+static void hist_trigger_elt_init(struct tracing_map_elt *elt)
+{
+ char *comm = elt->private_data;
+
+ if (comm)
+ save_comm(comm, current);
+}
+
+static struct tracing_map_ops hist_trigger_ops = {
+ .elt_alloc = hist_trigger_elt_alloc,
+ .elt_copy = hist_trigger_elt_copy,
+ .elt_free = hist_trigger_elt_free,
+ .elt_init = hist_trigger_elt_init,
+};
+
+static void destroy_hist_field(struct hist_field *hist_field)
+{
+ kfree(hist_field);
+}
+
+static struct hist_field *create_hist_field(struct ftrace_event_field *field,
+ unsigned long flags)
+{
+ struct hist_field *hist_field;
+
+ if (field && is_function_field(field))
+ return NULL;
+
+ hist_field = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
+ if (!hist_field)
+ return NULL;
+
+ if (flags & HIST_FIELD_HITCOUNT) {
+ hist_field->fn = hist_field_counter;
+ goto out;
+ }
+
+ if (flags & HIST_FIELD_STACKTRACE) {
+ hist_field->fn = hist_field_none;
+ goto out;
+ }
+
+ if (is_string_field(field)) {
+ flags |= HIST_FIELD_STRING;
+ hist_field->fn = hist_field_string;
+ } else {
+ hist_field->fn = select_value_fn(field->size,
+ field->is_signed);
+ if (!hist_field->fn) {
+ destroy_hist_field(hist_field);
+ return NULL;
+ }
+ }
+ out:
+ hist_field->field = field;
+ hist_field->flags = flags;
+
+ return hist_field;
+}
+
+static void destroy_hist_fields(struct hist_trigger_data *hist_data)
+{
+ unsigned int i;
+
+ for (i = 0; i < hist_data->n_fields; i++) {
+ destroy_hist_field(hist_data->fields[i]);
+ hist_data->fields[i] = NULL;
+ }
+}
+
+static int create_hitcount_val(struct hist_trigger_data *hist_data)
+{
+ hist_data->fields[HITCOUNT_IDX] =
+ create_hist_field(NULL, HIST_FIELD_HITCOUNT);
+ if (!hist_data->fields[HITCOUNT_IDX])
+ return -ENOMEM;
+
+ hist_data->n_vals++;
+
+ return 0;
+}
+
+static int create_val_field(struct hist_trigger_data *hist_data,
+ unsigned int val_idx,
+ struct trace_event_file *file,
+ char *field_str)
+{
+ struct ftrace_event_field *field = NULL;
+ unsigned long flags = 0;
+ char *field_name;
+ int ret = 0;
+
+ if (!strcmp(field_str, "hitcount"))
+ return ret;
+
+ field_name = strsep(&field_str, ".");
+ if (field_str) {
+ if (!strcmp(field_str, "sym"))
+ flags |= HIST_FIELD_SYM;
+ else if (!strcmp(field_str, "sym-offset"))
+ flags |= HIST_FIELD_SYM_OFFSET;
+ else if (!strcmp(field_str, "hex"))
+ flags |= HIST_FIELD_HEX;
+ else {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ field = trace_find_event_field(file->event_call, field_name);
+ if (!field) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ hist_data->fields[val_idx] = create_hist_field(field, flags);
+ if (!hist_data->fields[val_idx]) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ hist_data->n_vals++;
+ out:
+ return ret;
+}
+
+static int create_val_fields(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file)
+{
+ char *fields_str, *field_str;
+ unsigned int i;
+ int ret;
+
+ ret = create_hitcount_val(hist_data);
+ if (ret)
+ goto out;
+
+ fields_str = hist_data->attrs->vals_str;
+ if (!fields_str)
+ goto out;
+
+ strsep(&fields_str, "=");
+ if (!fields_str)
+ goto out;
+
+ for (i = 1; i < TRACING_MAP_FIELDS_MAX - 1; i++) {
+ field_str = strsep(&fields_str, ",");
+ if (!field_str)
+ break;
+ ret = create_val_field(hist_data, i, file, field_str);
+ if (ret)
+ goto out;
+ }
+ out:
+ return ret;
+}
+
+static int create_key_field(struct hist_trigger_data *hist_data,
+ unsigned int key_idx,
+ unsigned int key_offset,
+ struct trace_event_file *file,
+ char *field_str)
+{
+ struct ftrace_event_field *field = NULL;
+ unsigned long flags = 0;
+ unsigned int key_size;
+ char *field_name;
+ int ret = 0;
+
+ flags |= HIST_FIELD_KEY;
+
+ if (!strcmp(field_str, "stacktrace")) {
+ flags |= HIST_FIELD_STACKTRACE;
+ key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
+ } else {
+ field_name = strsep(&field_str, ".");
+ if (field_str) {
+ if (!strcmp(field_str, "sym"))
+ flags |= HIST_FIELD_SYM;
+ else if (!strcmp(field_str, "sym-offset"))
+ flags |= HIST_FIELD_SYM_OFFSET;
+ else if (!strcmp(field_str, "hex"))
+ flags |= HIST_FIELD_HEX;
+ else if (!strcmp(field_str, "execname") &&
+ !strcmp(field_name, "common_pid"))
+ flags |= HIST_FIELD_EXECNAME;
+ else if (!strcmp(field_str, "syscall"))
+ flags |= HIST_FIELD_SYSCALL;
+ else {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ field = trace_find_event_field(file->event_call, field_name);
+ if (!field) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ key_size = field->size;
+ }
+
+ hist_data->fields[key_idx] = create_hist_field(field, flags);
+ if (!hist_data->fields[key_idx]) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ key_size = ALIGN(key_size, sizeof(u64));
+ hist_data->fields[key_idx]->size = key_size;
+ hist_data->fields[key_idx]->offset = key_offset;
+ hist_data->key_size += key_size;
+ if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ hist_data->n_keys++;
+ ret = key_size;
+ out:
+ return ret;
+}
+
+static int create_key_fields(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file)
+{
+ unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
+ char *fields_str, *field_str;
+ int ret = -EINVAL;
+
+ fields_str = hist_data->attrs->keys_str;
+ if (!fields_str)
+ goto out;
+
+ strsep(&fields_str, "=");
+ if (!fields_str)
+ goto out;
+
+ for (i = n_vals; i < n_vals + HIST_KEY_MAX; i++) {
+ field_str = strsep(&fields_str, ",");
+ if (!field_str)
+ break;
+ ret = create_key_field(hist_data, i, key_offset, file, field_str);
+ if (ret < 0)
+ goto out;
+ key_offset += ret;
+ }
+ ret = 0;
+ out:
+ return ret;
+}
+
+static int create_hist_fields(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file)
+{
+ int ret;
+
+ ret = create_val_fields(hist_data, file);
+ if (ret)
+ goto out;
+
+ ret = create_key_fields(hist_data, file);
+ if (ret)
+ goto out;
+
+ hist_data->n_fields = hist_data->n_vals + hist_data->n_keys;
+ out:
+ return ret;
+}
+
+static int is_descending(const char *str)
+{
+ if (!str)
+ return 0;
+
+ if (!strcmp(str, "descending"))
+ return 1;
+
+ if (!strcmp(str, "ascending"))
+ return 0;
+
+ return -EINVAL;
+}
+
+static int create_sort_keys(struct hist_trigger_data *hist_data)
+{
+ char *fields_str = hist_data->attrs->sort_key_str;
+ struct ftrace_event_field *field = NULL;
+ struct tracing_map_sort_key *sort_key;
+ unsigned int i, j;
+ int ret = 1;
+
+ hist_data->n_sort_keys = 1;
+
+ if (!fields_str)
+ goto out;
+
+ strsep(&fields_str, "=");
+ if (!fields_str) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
+ char *field_str, *field_name;
+
+ sort_key = &hist_data->sort_keys[i];
+
+ field_str = strsep(&fields_str, ",");
+ if (!field_str) {
+ if (i == 0)
+ ret = -EINVAL;
+ break;
+ }
+
+ if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
+ ret = -EINVAL;
+ break;
+ }
+
+ field_name = strsep(&field_str, ".");
+ if (!field_name) {
+ ret = -EINVAL;
+ break;
+ }
+
+ if (!strcmp(field_name, "hitcount")) {
+ ret = is_descending(field_str);
+ if (ret < 0)
+ break;
+ sort_key->descending = ret;
+ continue;
+ }
+
+ for (j = 1; j < hist_data->n_fields; j++) {
+ field = hist_data->fields[j]->field;
+ if (field && !strcmp(field_name, field->name)) {
+ sort_key->field_idx = j;
+ ret = is_descending(field_str);
+ if (ret < 0)
+ goto out;
+ sort_key->descending = ret;
+ break;
+ }
+ }
+ if (j == hist_data->n_fields) {
+ ret = -EINVAL;
+ break;
+ }
+ }
+ hist_data->n_sort_keys = i;
+ out:
+ return ret;
+}
+
+static void destroy_hist_data(struct hist_trigger_data *hist_data)
+{
+ destroy_hist_trigger_attrs(hist_data->attrs);
+ destroy_hist_fields(hist_data);
+ tracing_map_destroy(hist_data->map);
+ kfree(hist_data);
+}
+
+static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
+{
+ struct tracing_map *map = hist_data->map;
+ struct ftrace_event_field *field;
+ struct hist_field *hist_field;
+ unsigned int i, idx;
+
+ for (i = 0; i < hist_data->n_fields; i++) {
+ hist_field = hist_data->fields[i];
+ if (hist_field->flags & HIST_FIELD_KEY) {
+ tracing_map_cmp_fn_t cmp_fn;
+
+ field = hist_field->field;
+
+ if (hist_field->flags & HIST_FIELD_STACKTRACE)
+ cmp_fn = tracing_map_cmp_none;
+ else if (is_string_field(field))
+ cmp_fn = tracing_map_cmp_string;
+ else
+ cmp_fn = tracing_map_cmp_num(field->size,
+ field->is_signed);
+ idx = tracing_map_add_key_field(map,
+ hist_field->offset,
+ cmp_fn);
+ } else
+ idx = tracing_map_add_sum_field(map);
+
+ if (idx < 0)
+ return idx;
+ }
+
+ return 0;
+}
+
+static struct hist_trigger_data *
+create_hist_data(unsigned int map_bits,
+ struct hist_trigger_attrs *attrs,
+ struct trace_event_file *file)
+{
+ struct hist_trigger_data *hist_data;
+ int ret = 0;
+
+ hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
+ if (!hist_data)
+ return ERR_PTR(-ENOMEM);
+
+ hist_data->attrs = attrs;
+
+ ret = create_hist_fields(hist_data, file);
+ if (ret < 0)
+ goto free;
+
+ ret = create_sort_keys(hist_data);
+ if (ret < 0)
+ goto free;
+
+ hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
+ &hist_trigger_ops,
+ hist_data);
+ if (IS_ERR(hist_data->map)) {
+ ret = PTR_ERR(hist_data->map);
+ hist_data->map = NULL;
+ goto free;
+ }
+
+ ret = create_tracing_map_fields(hist_data);
+ if (ret)
+ goto free;
+
+ ret = tracing_map_init(hist_data->map);
+ if (ret)
+ goto free;
+
+ hist_data->event_file = file;
+ out:
+ return hist_data;
+ free:
+ destroy_hist_data(hist_data);
+ if (ret)
+ hist_data = ERR_PTR(ret);
+ else
+ hist_data = NULL;
+
+ goto out;
+}
+
+static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
+ struct tracing_map_elt *elt,
+ void *rec)
+{
+ struct hist_field *hist_field;
+ unsigned int i;
+ u64 hist_val;
+
+ for (i = 0; i < hist_data->n_vals; i++) {
+ hist_field = hist_data->fields[i];
+ hist_val = hist_field->fn(hist_field, rec);
+ tracing_map_update_sum(elt, i, hist_val);
+ }
+}
+
+static void event_hist_trigger(struct event_trigger_data *data, void *rec)
+{
+ struct hist_trigger_data *hist_data = data->private_data;
+ unsigned long entries[HIST_STACKTRACE_DEPTH];
+ char compound_key[HIST_KEY_SIZE_MAX];
+ struct stack_trace stacktrace;
+ struct hist_field *key_field;
+ struct tracing_map_elt *elt;
+ u64 field_contents;
+ void *key = NULL;
+ unsigned int i;
+
+ if (atomic64_read(&hist_data->drops)) {
+ atomic64_inc(&hist_data->drops);
+ return;
+ }
+
+ if (hist_data->n_keys > 1)
+ memset(compound_key, 0, hist_data->key_size);
+
+ for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
+ key_field = hist_data->fields[i];
+
+ if (key_field->flags & HIST_FIELD_STACKTRACE) {
+ stacktrace.max_entries = HIST_STACKTRACE_DEPTH;
+ stacktrace.entries = entries;
+ stacktrace.nr_entries = 0;
+ stacktrace.skip = HIST_STACKTRACE_SKIP;
+
+ memset(stacktrace.entries, 0, hist_data->key_size);
+ save_stack_trace(&stacktrace);
+
+ key = entries;
+ } else {
+ field_contents = key_field->fn(key_field, rec);
+ if (key_field->flags & HIST_FIELD_STRING)
+ key = (void *)field_contents;
+ else
+ key = (void *)&field_contents;
+
+ if (hist_data->n_keys > 1) {
+ memcpy(compound_key + key_field->offset, key,
+ key_field->size);
+ }
+ }
+ }
+
+ if (hist_data->n_keys > 1)
+ key = compound_key;
+
+ elt = tracing_map_insert(hist_data->map, key);
+ if (elt)
+ hist_trigger_elt_update(hist_data, elt, rec);
+ else
+ atomic64_inc(&hist_data->drops);
+
+ atomic64_inc(&hist_data->total_hits);
+}
+
+static void hist_trigger_stacktrace_print(struct seq_file *m,
+ unsigned long *stacktrace_entries,
+ unsigned int max_entries)
+{
+ char str[KSYM_SYMBOL_LEN];
+ unsigned int spaces = 8;
+ unsigned int i;
+
+ for (i = 0; i < max_entries; i++) {
+ if (stacktrace_entries[i] == ULONG_MAX)
+ return;
+
+ seq_printf(m, "%*c", 1 + spaces, ' ');
+ sprint_symbol(str, stacktrace_entries[i]);
+ seq_printf(m, "%s\n", str);
+ }
+}
+
+static void
+hist_trigger_entry_print(struct seq_file *m,
+ struct hist_trigger_data *hist_data, void *key,
+ struct tracing_map_elt *elt)
+{
+ struct hist_field *key_field;
+ char str[KSYM_SYMBOL_LEN];
+ bool multiline = false;
+ unsigned int i;
+ u64 uval;
+
+ seq_puts(m, "{ ");
+
+ for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
+ key_field = hist_data->fields[i];
+
+ if (i > hist_data->n_vals)
+ seq_puts(m, ", ");
+
+ if (key_field->flags & HIST_FIELD_SYM) {
+ uval = *(u64 *)(key + key_field->offset);
+ sprint_symbol_no_offset(str, uval);
+ seq_printf(m, "%s: [%llx] %-45s",
+ key_field->field->name, uval, str);
+ } else if (key_field->flags & HIST_FIELD_SYM_OFFSET) {
+ uval = *(u64 *)(key + key_field->offset);
+ sprint_symbol(str, uval);
+ seq_printf(m, "%s: [%llx] %-55s",
+ key_field->field->name, uval, str);
+ } else if (key_field->flags & HIST_FIELD_HEX) {
+ uval = *(u64 *)(key + key_field->offset);
+ seq_printf(m, "%s: %llx",
+ key_field->field->name, uval);
+ } else if (key_field->flags & HIST_FIELD_STACKTRACE) {
+ seq_puts(m, "stacktrace:\n");
+ hist_trigger_stacktrace_print(m,
+ key + key_field->offset,
+ HIST_STACKTRACE_DEPTH);
+ multiline = true;
+ } else if (key_field->flags & HIST_FIELD_STRING) {
+ seq_printf(m, "%s: %-35s", key_field->field->name,
+ (char *)(key + key_field->offset));
+ } else if (key_field->flags & HIST_FIELD_EXECNAME) {
+ char *comm = elt->private_data;
+
+ uval = *(u64 *)(key + key_field->offset);
+ seq_printf(m, "%s: %-16s[%10llu]",
+ key_field->field->name, comm, uval);
+ } else if (key_field->flags & HIST_FIELD_SYSCALL) {
+ const char *syscall_name;
+
+ uval = *(u64 *)(key + key_field->offset);
+ syscall_name = get_syscall_name(uval);
+ if (!syscall_name)
+ syscall_name = "unknown_syscall";
+
+ seq_printf(m, "%s: %-30s[%3llu]",
+ key_field->field->name, syscall_name, uval);
+ } else {
+ uval = *(u64 *)(key + key_field->offset);
+ seq_printf(m, "%s: %10llu",
+ key_field->field->name, uval);
+ }
+ }
+
+ if (!multiline)
+ seq_puts(m, " ");
+
+ seq_puts(m, "}");
+
+ seq_printf(m, " hitcount: %10llu",
+ tracing_map_read_sum(elt, HITCOUNT_IDX));
+
+ for (i = 1; i < hist_data->n_vals; i++) {
+ seq_printf(m, " %s: %10llu",
+ hist_data->fields[i]->field->name,
+ tracing_map_read_sum(elt, i));
+ }
+
+ seq_puts(m, "\n");
+}
+
+static int print_entries(struct seq_file *m,
+ struct hist_trigger_data *hist_data)
+{
+ struct tracing_map_sort_entry **sort_entries = NULL;
+ struct tracing_map *map = hist_data->map;
+ unsigned int i, n_entries;
+
+ n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
+ hist_data->n_sort_keys,
+ &sort_entries);
+ if (n_entries < 0)
+ return n_entries;
+
+ for (i = 0; i < n_entries; i++)
+ hist_trigger_entry_print(m, hist_data,
+ sort_entries[i]->key,
+ sort_entries[i]->elt);
+
+ tracing_map_destroy_sort_entries(sort_entries, n_entries);
+
+ return n_entries;
+}
+
+static int hist_show(struct seq_file *m, void *v)
+{
+ struct event_trigger_data *test, *data = NULL;
+ struct trace_event_file *event_file;
+ struct hist_trigger_data *hist_data;
+ int n_entries, ret = 0;
+
+ mutex_lock(&event_mutex);
+
+ event_file = event_file_data(m->private);
+ if (unlikely(!event_file)) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ list_for_each_entry_rcu(test, &event_file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ data = test;
+ break;
+ }
+ }
+ if (!data)
+ goto out_unlock;
+
+ seq_puts(m, "# trigger info: ");
+ data->ops->print(m, data->ops, data);
+ seq_puts(m, "\n");
+
+ hist_data = data->private_data;
+ n_entries = print_entries(m, hist_data);
+ if (n_entries < 0) {
+ ret = n_entries;
+ n_entries = 0;
+ }
+
+ seq_printf(m, "\nTotals:\n Hits: %lu\n Entries: %u\n Dropped: %lu\n",
+ atomic64_read(&hist_data->total_hits),
+ n_entries, atomic64_read(&hist_data->drops));
+ out_unlock:
+ mutex_unlock(&event_mutex);
+
+ return ret;
+}
+
+static int event_hist_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, hist_show, file);
+}
+
+const struct file_operations event_hist_fops = {
+ .open = event_hist_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static const char *get_hist_field_flags(struct hist_field *hist_field)
+{
+ const char *flags_str = NULL;
+
+ if (hist_field->flags & HIST_FIELD_SYM)
+ flags_str = "sym";
+ else if (hist_field->flags & HIST_FIELD_SYM_OFFSET)
+ flags_str = "sym-offset";
+ else if (hist_field->flags & HIST_FIELD_HEX)
+ flags_str = "hex";
+ else if (hist_field->flags & HIST_FIELD_SYSCALL)
+ flags_str = "syscall";
+ else if (hist_field->flags & HIST_FIELD_EXECNAME)
+ flags_str = "execname";
+
+ return flags_str;
+}
+
+static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
+{
+ seq_printf(m, "%s", hist_field->field->name);
+ if (hist_field->flags) {
+ const char *flags_str = get_hist_field_flags(hist_field);
+
+ if (flags_str)
+ seq_printf(m, ".%s", flags_str);
+ }
+}
+
+static int event_hist_trigger_print(struct seq_file *m,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+ struct hist_trigger_data *hist_data = data->private_data;
+ struct hist_field *key_field;
+ unsigned int i;
+
+ seq_puts(m, "hist:keys=");
+
+ for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
+ key_field = hist_data->fields[i];
+
+ if (i > hist_data->n_vals)
+ seq_puts(m, ",");
+
+ if (key_field->flags & HIST_FIELD_STACKTRACE)
+ seq_puts(m, "stacktrace");
+ else
+ hist_field_print(m, key_field);
+ }
+
+ seq_puts(m, ":vals=");
+
+ if (hist_data->n_vals == 1)
+ seq_puts(m, "hitcount");
+ else {
+ for (i = 1; i < hist_data->n_vals; i++) {
+ if (i > 1)
+ seq_puts(m, ",");
+ hist_field_print(m, hist_data->fields[i]);
+ }
+ }
+
+ seq_puts(m, ":sort=");
+
+ for (i = 0; i < hist_data->n_sort_keys; i++) {
+ struct tracing_map_sort_key *sort_key;
+
+ sort_key = &hist_data->sort_keys[i];
+
+ if (i > 0)
+ seq_puts(m, ",");
+
+ if (sort_key->field_idx == HITCOUNT_IDX)
+ seq_puts(m, "hitcount");
+ else {
+ unsigned int idx = sort_key->field_idx;
+
+ hist_field_print(m, hist_data->fields[idx]);
+ }
+
+ if (sort_key->descending)
+ seq_puts(m, ".descending");
+ }
+
+ seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));
+
+ if (data->filter_str)
+ seq_printf(m, " if %s", data->filter_str);
+
+ if (data->paused)
+ seq_puts(m, " [paused]");
+ else
+ seq_puts(m, " [active]");
+
+ seq_putc(m, '\n');
+
+ return 0;
+}
+
+static void event_hist_trigger_free(struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+ struct hist_trigger_data *hist_data = data->private_data;
+
+ if (WARN_ON_ONCE(data->ref <= 0))
+ return;
+
+ data->ref--;
+ if (!data->ref) {
+ trigger_data_free(data);
+ destroy_hist_data(hist_data);
+ }
+}
+
+static struct event_trigger_ops event_hist_trigger_ops = {
+ .func = event_hist_trigger,
+ .print = event_hist_trigger_print,
+ .init = event_trigger_init,
+ .free = event_hist_trigger_free,
+};
+
+static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
+ char *param)
+{
+ return &event_hist_trigger_ops;
+}
+
+static void hist_clear(struct event_trigger_data *data)
+{
+ struct hist_trigger_data *hist_data = data->private_data;
+ bool paused;
+
+ paused = data->paused;
+ data->paused = true;
+
+ synchronize_sched();
+
+ tracing_map_clear(hist_data->map);
+
+ atomic64_set(&hist_data->total_hits, 0);
+ atomic64_set(&hist_data->drops, 0);
+
+ data->paused = paused;
+}
+
+static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,
+ struct event_trigger_data *data,
+ struct trace_event_file *file)
+{
+ struct hist_trigger_data *hist_data = data->private_data;
+ struct event_trigger_data *test;
+ int ret = 0;
+
+ list_for_each_entry_rcu(test, &file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ if (hist_data->attrs->clear)
+ hist_clear(test);
+ else if (hist_data->attrs->pause)
+ test->paused = true;
+ else if (hist_data->attrs->cont)
+ test->paused = false;
+ else
+ ret = -EEXIST;
+ goto out;
+ }
+ }
+
+ if (hist_data->attrs->pause)
+ data->paused = true;
+
+ if (data->ops->init) {
+ ret = data->ops->init(data->ops, data);
+ if (ret < 0)
+ goto out;
+ }
+
+ list_add_rcu(&data->list, &file->triggers);
+ ret++;
+
+ update_cond_flag(file);
+ if (trace_event_trigger_enable_disable(file, 1) < 0) {
+ list_del_rcu(&data->list);
+ update_cond_flag(file);
+ ret--;
+ }
+ out:
+ return ret;
+}
+
+static int event_hist_trigger_func(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param)
+{
+ unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
+ struct event_trigger_data *trigger_data;
+ struct hist_trigger_attrs *attrs;
+ struct event_trigger_ops *trigger_ops;
+ struct hist_trigger_data *hist_data;
+ char *trigger;
+ int ret = 0;
+
+ if (!param)
+ return -EINVAL;
+
+ /* separate the trigger from the filter (k:v [if filter]) */
+ trigger = strsep(¶m, " \t");
+ if (!trigger)
+ return -EINVAL;
+
+ attrs = parse_hist_trigger_attrs(trigger);
+ if (IS_ERR(attrs))
+ return PTR_ERR(attrs);
+
+ if (!attrs->keys_str)
+ return -EINVAL;
+
+ if (attrs->map_bits)
+ hist_trigger_bits = attrs->map_bits;
+
+ hist_data = create_hist_data(hist_trigger_bits, attrs, file);
+ if (IS_ERR(hist_data))
+ return PTR_ERR(hist_data);
+
+ trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
+
+ ret = -ENOMEM;
+ trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
+ if (!trigger_data)
+ goto out;
+
+ trigger_data->count = -1;
+ trigger_data->ops = trigger_ops;
+ trigger_data->cmd_ops = cmd_ops;
+
+ INIT_LIST_HEAD(&trigger_data->list);
+ RCU_INIT_POINTER(trigger_data->filter, NULL);
+
+ trigger_data->private_data = hist_data;
+
+ if (glob[0] == '!') {
+ cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
+ ret = 0;
+ goto out_free;
+ }
+
+ if (!param) /* if param is non-empty, it's supposed to be a filter */
+ goto out_reg;
+
+ if (!cmd_ops->set_filter)
+ goto out_reg;
+
+ ret = cmd_ops->set_filter(param, trigger_data, file);
+ if (ret < 0)
+ goto out_free;
+ out_reg:
+ ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
+ /*
+ * The above returns on success the # of triggers registered,
+ * but if it didn't register any it returns zero. Consider no
+ * triggers registered a failure too.
+ */
+ if (!ret) {
+ if (!(attrs->pause || attrs->cont || attrs->clear))
+ ret = -ENOENT;
+ goto out_free;
+ } else if (ret < 0)
+ goto out_free;
+ /* Just return zero, not the number of registered triggers */
+ ret = 0;
+ out:
+ return ret;
+ out_free:
+ if (cmd_ops->set_filter)
+ cmd_ops->set_filter(NULL, trigger_data, NULL);
+
+ kfree(trigger_data);
+
+ destroy_hist_data(hist_data);
+ goto out;
+}
+
+static struct event_command trigger_hist_cmd = {
+ .name = "hist",
+ .trigger_type = ETT_EVENT_HIST,
+ .post_trigger = true, /* need non-NULL rec */
+ .func = event_hist_trigger_func,
+ .reg = hist_register_trigger,
+ .unreg = unregister_trigger,
+ .get_trigger_ops = event_hist_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+__init int register_trigger_hist_cmd(void)
+{
+ int ret;
+
+ ret = register_event_command(&trigger_hist_cmd);
+ WARN_ON(ret < 0);
+
+ return ret;
+}
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index ecf65e1..e80f30b 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -28,8 +28,7 @@
static LIST_HEAD(trigger_commands);
static DEFINE_MUTEX(trigger_cmd_mutex);
-static void
-trigger_data_free(struct event_trigger_data *data)
+void trigger_data_free(struct event_trigger_data *data)
{
if (data->cmd_ops->set_filter)
data->cmd_ops->set_filter(NULL, data, NULL);
@@ -316,7 +315,7 @@ const struct file_operations event_trigger_fops = {
* Currently we only register event commands from __init, so mark this
* __init too.
*/
-static __init int register_event_command(struct event_command *cmd)
+__init int register_event_command(struct event_command *cmd)
{
struct event_command *p;
int ret = 0;
@@ -405,9 +404,8 @@ event_trigger_print(const char *name, struct seq_file *m,
*
* Return: 0 on success, errno otherwise
*/
-static int
-event_trigger_init(struct event_trigger_ops *ops,
- struct event_trigger_data *data)
+int event_trigger_init(struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
{
data->ref++;
return 0;
@@ -435,8 +433,8 @@ event_trigger_free(struct event_trigger_ops *ops,
trigger_data_free(data);
}
-static int trace_event_trigger_enable_disable(struct trace_event_file *file,
- int trigger_enable)
+int trace_event_trigger_enable_disable(struct trace_event_file *file,
+ int trigger_enable)
{
int ret = 0;
@@ -493,7 +491,7 @@ clear_event_triggers(struct trace_array *tr)
* its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
* cleared.
*/
-static void update_cond_flag(struct trace_event_file *file)
+void update_cond_flag(struct trace_event_file *file)
{
struct event_trigger_data *data;
bool set_cond = false;
@@ -570,9 +568,9 @@ out:
* Usually used directly as the @unreg method in event command
* implementations.
*/
-static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
- struct event_trigger_data *test,
- struct trace_event_file *file)
+void unregister_trigger(char *glob, struct event_trigger_ops *ops,
+ struct event_trigger_data *test,
+ struct trace_event_file *file)
{
struct event_trigger_data *data;
bool unregistered = false;
@@ -706,9 +704,9 @@ event_trigger_callback(struct event_command *cmd_ops,
*
* Return: 0 on success, errno otherwise
*/
-static int set_trigger_filter(char *filter_str,
- struct event_trigger_data *trigger_data,
- struct trace_event_file *file)
+int set_trigger_filter(char *filter_str,
+ struct event_trigger_data *trigger_data,
+ struct trace_event_file *file)
{
struct event_trigger_data *data = trigger_data;
struct event_filter *filter = NULL, *tmp;
@@ -1439,6 +1437,7 @@ __init int register_trigger_cmds(void)
register_trigger_snapshot_cmd();
register_trigger_stacktrace_cmd();
register_trigger_enable_disable_cmds();
+ register_trigger_hist_cmd();
return 0;
}
--
1.9.3
Similar to enable_event/disable_event triggers, these triggers enable
and disable the aggregation of events into maps rather than enabling
and disabling their writing into the trace buffer.
They can be used to automatically start and stop hist triggers based
on a matching filter condition.
If there's a paused hist trigger on system:event, the following would
start it when the filter condition was hit:
# echo enable_hist:system:event [ if filter] > event/trigger
And the following would disable a running system:event hist trigger:
# echo disable_hist:system:event [ if filter] > event/trigger
See Documentation/trace/events.txt for real examples.
Signed-off-by: Tom Zanussi <[email protected]>
---
include/linux/trace_events.h | 1 +
kernel/trace/trace.c | 11 ++++
kernel/trace/trace.h | 32 ++++++++++
kernel/trace/trace_events_hist.c | 115 ++++++++++++++++++++++++++++++++++++
kernel/trace/trace_events_trigger.c | 71 ++++++++++++----------
5 files changed, 199 insertions(+), 31 deletions(-)
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 0faf48b..0f3ffdd 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -411,6 +411,7 @@ enum event_trigger_type {
ETT_STACKTRACE = (1 << 2),
ETT_EVENT_ENABLE = (1 << 3),
ETT_EVENT_HIST = (1 << 4),
+ ETT_HIST_ENABLE = (1 << 5),
};
extern int filter_match_preds(struct event_filter *filter, void *rec);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c37c2d5..6c1a38a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3761,6 +3761,10 @@ static const char readme_msg[] =
"\t trigger: traceon, traceoff\n"
"\t enable_event:<system>:<event>\n"
"\t disable_event:<system>:<event>\n"
+#ifdef CONFIG_HIST_TRIGGERS
+ "\t enable_hist:<system>:<event>\n"
+ "\t disable_hist:<system>:<event>\n"
+#endif
#ifdef CONFIG_STACKTRACE
"\t\t stacktrace\n"
#endif
@@ -3836,6 +3840,13 @@ static const char readme_msg[] =
"\t restart a paused hist trigger.\n\n"
"\t The 'clear' param will clear the contents of a running hist\n"
"\t trigger and leave its current paused/active state.\n\n"
+ "\t The enable_hist and disable_hist triggers can be used to\n"
+ "\t have one event conditionally start and stop another event's\n"
+ "\t already-attached hist trigger. Any number of enable_hist\n"
+ "\t and disable_hist triggers can be attached to a given event,\n"
+ "\t allowing that event to kick off and stop aggregations on\n"
+ "\t a host of other events. See Documentation/trace/events.txt\n"
+ "\t for examples.\n"
#endif
;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e6cb781..5e2e3b0 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1102,8 +1102,10 @@ extern const struct file_operations event_hist_fops;
#ifdef CONFIG_HIST_TRIGGERS
extern int register_trigger_hist_cmd(void);
+extern int register_trigger_hist_enable_disable_cmds(void);
#else
static inline int register_trigger_hist_cmd(void) { return 0; }
+static inline int register_trigger_hist_enable_disable_cmds(void) { return 0; }
#endif
extern int register_trigger_cmds(void);
@@ -1121,6 +1123,34 @@ struct event_trigger_data {
struct list_head list;
};
+/* Avoid typos */
+#define ENABLE_EVENT_STR "enable_event"
+#define DISABLE_EVENT_STR "disable_event"
+#define ENABLE_HIST_STR "enable_hist"
+#define DISABLE_HIST_STR "disable_hist"
+
+struct enable_trigger_data {
+ struct trace_event_file *file;
+ bool enable;
+ bool hist;
+};
+
+extern int event_enable_trigger_print(struct seq_file *m,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data);
+extern void event_enable_trigger_free(struct event_trigger_ops *ops,
+ struct event_trigger_data *data);
+extern int event_enable_trigger_func(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param);
+extern int event_enable_register_trigger(char *glob,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data,
+ struct trace_event_file *file);
+extern void event_enable_unregister_trigger(char *glob,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *test,
+ struct trace_event_file *file);
extern void trigger_data_free(struct event_trigger_data *data);
extern int event_trigger_init(struct event_trigger_ops *ops,
struct event_trigger_data *data);
@@ -1134,6 +1164,8 @@ extern int set_trigger_filter(char *filter_str,
struct event_trigger_data *trigger_data,
struct trace_event_file *file);
extern int register_event_command(struct event_command *cmd);
+extern int unregister_event_command(struct event_command *cmd);
+extern int register_trigger_hist_enable_disable_cmds(void);
/**
* struct event_trigger_ops - callbacks for trace event triggers
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index e005683..5ea1895 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1290,3 +1290,118 @@ __init int register_trigger_hist_cmd(void)
return ret;
}
+
+static void
+hist_enable_trigger(struct event_trigger_data *data, void *rec)
+{
+ struct enable_trigger_data *enable_data = data->private_data;
+ struct event_trigger_data *test;
+
+ list_for_each_entry_rcu(test, &enable_data->file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ if (enable_data->enable)
+ test->paused = false;
+ else
+ test->paused = true;
+ break;
+ }
+ }
+}
+
+static void
+hist_enable_count_trigger(struct event_trigger_data *data, void *rec)
+{
+ if (!data->count)
+ return;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ hist_enable_trigger(data, rec);
+}
+
+static struct event_trigger_ops hist_enable_trigger_ops = {
+ .func = hist_enable_trigger,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
+};
+
+static struct event_trigger_ops hist_enable_count_trigger_ops = {
+ .func = hist_enable_count_trigger,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
+};
+
+static struct event_trigger_ops hist_disable_trigger_ops = {
+ .func = hist_enable_trigger,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
+};
+
+static struct event_trigger_ops hist_disable_count_trigger_ops = {
+ .func = hist_enable_count_trigger,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
+};
+
+static struct event_trigger_ops *
+hist_enable_get_trigger_ops(char *cmd, char *param)
+{
+ struct event_trigger_ops *ops;
+ bool enable;
+
+ enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);
+
+ if (enable)
+ ops = param ? &hist_enable_count_trigger_ops :
+ &hist_enable_trigger_ops;
+ else
+ ops = param ? &hist_disable_count_trigger_ops :
+ &hist_disable_trigger_ops;
+
+ return ops;
+}
+
+static struct event_command trigger_hist_enable_cmd = {
+ .name = ENABLE_HIST_STR,
+ .trigger_type = ETT_HIST_ENABLE,
+ .func = event_enable_trigger_func,
+ .reg = event_enable_register_trigger,
+ .unreg = event_enable_unregister_trigger,
+ .get_trigger_ops = hist_enable_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+static struct event_command trigger_hist_disable_cmd = {
+ .name = DISABLE_HIST_STR,
+ .trigger_type = ETT_HIST_ENABLE,
+ .func = event_enable_trigger_func,
+ .reg = event_enable_register_trigger,
+ .unreg = event_enable_unregister_trigger,
+ .get_trigger_ops = hist_enable_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+static __init void unregister_trigger_hist_enable_disable_cmds(void)
+{
+ unregister_event_command(&trigger_hist_enable_cmd);
+ unregister_event_command(&trigger_hist_disable_cmd);
+}
+
+__init int register_trigger_hist_enable_disable_cmds(void)
+{
+ int ret;
+
+ ret = register_event_command(&trigger_hist_enable_cmd);
+ if (WARN_ON(ret < 0))
+ return ret;
+ ret = register_event_command(&trigger_hist_disable_cmd);
+ if (WARN_ON(ret < 0))
+ unregister_trigger_hist_enable_disable_cmds();
+
+ return ret;
+}
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index e80f30b..9490d8f 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -338,7 +338,7 @@ __init int register_event_command(struct event_command *cmd)
* Currently we only unregister event commands from __init, so mark
* this __init too.
*/
-static __init int unregister_event_command(struct event_command *cmd)
+__init int unregister_event_command(struct event_command *cmd)
{
struct event_command *p, *n;
int ret = -ENODEV;
@@ -1052,15 +1052,6 @@ static __init void unregister_trigger_traceon_traceoff_cmds(void)
unregister_event_command(&trigger_traceoff_cmd);
}
-/* Avoid typos */
-#define ENABLE_EVENT_STR "enable_event"
-#define DISABLE_EVENT_STR "disable_event"
-
-struct enable_trigger_data {
- struct trace_event_file *file;
- bool enable;
-};
-
static void
event_enable_trigger(struct event_trigger_data *data, void *rec)
{
@@ -1090,14 +1081,16 @@ event_enable_count_trigger(struct event_trigger_data *data, void *rec)
event_enable_trigger(data, rec);
}
-static int
-event_enable_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
- struct event_trigger_data *data)
+int event_enable_trigger_print(struct seq_file *m,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
{
struct enable_trigger_data *enable_data = data->private_data;
seq_printf(m, "%s:%s:%s",
- enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
+ enable_data->hist ?
+ (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
+ (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
enable_data->file->event_call->class->system,
trace_event_name(enable_data->file->event_call));
@@ -1114,9 +1107,8 @@ event_enable_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
return 0;
}
-static void
-event_enable_trigger_free(struct event_trigger_ops *ops,
- struct event_trigger_data *data)
+void event_enable_trigger_free(struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
{
struct enable_trigger_data *enable_data = data->private_data;
@@ -1161,10 +1153,9 @@ static struct event_trigger_ops event_disable_count_trigger_ops = {
.free = event_enable_trigger_free,
};
-static int
-event_enable_trigger_func(struct event_command *cmd_ops,
- struct trace_event_file *file,
- char *glob, char *cmd, char *param)
+int event_enable_trigger_func(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param)
{
struct trace_event_file *event_enable_file;
struct enable_trigger_data *enable_data;
@@ -1173,6 +1164,7 @@ event_enable_trigger_func(struct event_command *cmd_ops,
struct trace_array *tr = file->tr;
const char *system;
const char *event;
+ bool hist = false;
char *trigger;
char *number;
bool enable;
@@ -1197,8 +1189,15 @@ event_enable_trigger_func(struct event_command *cmd_ops,
if (!event_enable_file)
goto out;
- enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
+#ifdef CONFIG_HIST_TRIGGERS
+ hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
+ (strcmp(cmd, DISABLE_HIST_STR) == 0));
+ enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
+ (strcmp(cmd, ENABLE_HIST_STR) == 0));
+#else
+ enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
+#endif
trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
ret = -ENOMEM;
@@ -1218,6 +1217,7 @@ event_enable_trigger_func(struct event_command *cmd_ops,
INIT_LIST_HEAD(&trigger_data->list);
RCU_INIT_POINTER(trigger_data->filter, NULL);
+ enable_data->hist = hist;
enable_data->enable = enable;
enable_data->file = event_enable_file;
trigger_data->private_data = enable_data;
@@ -1295,10 +1295,10 @@ event_enable_trigger_func(struct event_command *cmd_ops,
goto out;
}
-static int event_enable_register_trigger(char *glob,
- struct event_trigger_ops *ops,
- struct event_trigger_data *data,
- struct trace_event_file *file)
+int event_enable_register_trigger(char *glob,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data,
+ struct trace_event_file *file)
{
struct enable_trigger_data *enable_data = data->private_data;
struct enable_trigger_data *test_enable_data;
@@ -1308,6 +1308,8 @@ static int event_enable_register_trigger(char *glob,
list_for_each_entry_rcu(test, &file->triggers, list) {
test_enable_data = test->private_data;
if (test_enable_data &&
+ (test->cmd_ops->trigger_type ==
+ data->cmd_ops->trigger_type) &&
(test_enable_data->file == enable_data->file)) {
ret = -EEXIST;
goto out;
@@ -1333,10 +1335,10 @@ out:
return ret;
}
-static void event_enable_unregister_trigger(char *glob,
- struct event_trigger_ops *ops,
- struct event_trigger_data *test,
- struct trace_event_file *file)
+void event_enable_unregister_trigger(char *glob,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *test,
+ struct trace_event_file *file)
{
struct enable_trigger_data *test_enable_data = test->private_data;
struct enable_trigger_data *enable_data;
@@ -1346,6 +1348,8 @@ static void event_enable_unregister_trigger(char *glob,
list_for_each_entry_rcu(data, &file->triggers, list) {
enable_data = data->private_data;
if (enable_data &&
+ (data->cmd_ops->trigger_type ==
+ test->cmd_ops->trigger_type) &&
(enable_data->file == test_enable_data->file)) {
unregistered = true;
list_del_rcu(&data->list);
@@ -1365,8 +1369,12 @@ event_enable_get_trigger_ops(char *cmd, char *param)
struct event_trigger_ops *ops;
bool enable;
+#ifdef CONFIG_HIST_TRIGGERS
+ enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
+ (strcmp(cmd, ENABLE_HIST_STR) == 0));
+#else
enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
-
+#endif
if (enable)
ops = param ? &event_enable_count_trigger_ops :
&event_enable_trigger_ops;
@@ -1437,6 +1445,7 @@ __init int register_trigger_cmds(void)
register_trigger_snapshot_cmd();
register_trigger_stacktrace_cmd();
register_trigger_enable_disable_cmds();
+ register_trigger_hist_enable_disable_cmds();
register_trigger_hist_cmd();
return 0;
--
1.9.3
Add documentation and usage examples for 'hist' triggers.
Signed-off-by: Tom Zanussi <[email protected]>
---
Documentation/trace/events.txt | 1131 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 1131 insertions(+)
diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt
index 75d25a1..fb55ac3 100644
--- a/Documentation/trace/events.txt
+++ b/Documentation/trace/events.txt
@@ -494,3 +494,1134 @@ The following commands are supported:
Note that there can be only one traceon or traceoff trigger per
triggering event.
+
+- hist
+
+ This command aggregates event hits into a hash table keyed on one or
+ more trace event format fields (or stacktrace) and a set of running
+ totals derived from one or more trace event format fields and/or
+ event counts (hitcount).
+
+ The format of a hist trigger is as follows:
+
+ hist:keys=<field1>[,field2,...][:values=<field1>[,field2,...]]
+ [:sort=field1,field2,...][:size=#entries][:pause][:continue]
+ [:clear] [if <filter>]
+
+ When a matching event is hit, an entry is added to a hash table
+ using the key(s) and value(s) named. Keys and values correspond to
+ fields in the event's format description. Values must correspond to
+ numeric fields - on an event hit, the value(s) will be added to a
+ sum kept for that field. The special string 'hitcount' can be used
+ in place of an explicit value field - this is simply a count of
+ event hits. If 'values' isn't specified, an implicit 'hitcount'
+ value will be automatically created and used as the only value.
+ Keys can be any field, or the special string 'stacktrace', which
+ will use the event's kernel stacktrace as the key. The keywords
+ 'keys' or 'key' can be used to specify keys, and the keywords
+ 'values', 'vals', or 'val' can be used to specify values. Compound
+ keys consisting of up to two fields can be specified by the 'keys'
+ keyword. Hashing a compound key produces a unique entry in the
+ table for each unique combination of component keys, and can be
+ useful for providing more fine-grained summaries of event data.
+ Additionally, sort keys consisting of up to two fields can be
+ specified by the 'sort' keyword. If more than one field is
+ specified, the result will be a 'sort within a sort': the first key
+ is taken to be the primary sort key and the second the secondary
+ key.
+
+ 'hist' triggers add a 'hist' file to each event's subdirectory.
+ Reading the 'hist' file for the event will dump the hash table in
+ its entirety to stdout. Each printed hash table entry is a simple
+ list of the keys and values comprising the entry; keys are printed
+ first and are delineated by curly braces, and are followed by the
+ set of value fields for the entry. By default, numeric fields are
+ displayed as base-10 integers. This can be modified by appending
+ any of the following modifiers to the field name:
+
+ .hex display a number as a hex value
+ .sym display an address as a symbol
+ .sym-offset display an address as a symbol and offset
+ .syscall display a syscall id as a system call name
+ .execname display a common_pid as a program name
+
+ A typical usage scenario would be the following to enable a hist
+ trigger, read its current contents, and then turn it off:
+
+ # echo 'hist:keys=skbaddr.hex:vals=len' > \
+ /sys/kernel/debug/tracing/events/net/netif_rx/trigger
+
+ # cat /sys/kernel/debug/tracing/events/net/netif_rx/hist
+
+ # echo '!hist:keys=skbaddr.hex:vals=len' > \
+ /sys/kernel/debug/tracing/events/net/netif_rx/trigger
+
+ The trigger file itself can be read to show the details of the
+ currently attached hist trigger. This information is also displayed
+ at the top of the 'hist' file when read.
+
+ By default, the size of the hash table is 2048 entries. The 'size'
+ param can be used to specify more or fewer than that. The units are
+ in terms of hashtable entries - if a run uses more entries than
+ specified, the results will show the number of 'drops', the number
+ of hits that were ignored. The size should be a power of 2 between
+ 128 and 131072 (any non- power-of-2 number specified will be rounded
+ up).
+
+ The 'sort' param can be used to specify a value field to sort on.
+ The default if unspecified is 'hitcount' and the default sort order
+ is 'ascending'. To sort in the opposite direction, append
+ .descending' to the sort key.
+
+ The 'pause' param can be used to pause an existing hist trigger or
+ to start a hist trigger but not log any events until told to do so.
+ 'continue' or 'cont' can be used to start or restart a paused hist
+ trigger.
+
+ The 'clear' param will clear the contents of a running hist trigger
+ and leave its current paused/active state.
+
+- enable_hist/disable_hist
+
+ The enable_hist and disable_hist triggers can be used to have one
+ event conditionally start and stop another event's already-attached
+ hist trigger. Any number of enable_hist and disable_hist triggers
+ can be attached to a given event, allowing that event to kick off
+ and stop aggregations on a host of other events.
+
+ The format is very similar to the enable/disable_event triggers:
+
+ enable_hist:<system>:<event>[:count]
+ disable_hist:<system>:<event>[:count]
+
+ Instead of enabling or disabling the tracing of the target event
+ into the trace buffer as the enable/disable_event triggers do, the
+ enable/disable_hist triggers enable or disable the aggregation of
+ the target event into a hash table.
+
+ A typical usage scenario for the enable_hist/disable_hist triggers
+ would be to first set up a paused hist trigger on some event,
+ followed by an enable_hist/disable_hist pair that turns the hist
+ aggregation on and off when conditions of interest are hit:
+
+ # echo 'hist:keys=skbaddr.hex:vals=len:pause' > \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+
+ # echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
+
+ # echo 'disable_hist:net:netif_receive_skb if comm==wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
+
+ The above sets up an initially paused hist trigger which is unpaused
+ and starts aggregating events when a given program is executed, and
+ which stops aggregating when the process exits and the hist trigger
+ is paused again.
+
+ The examples below provide a more concrete illustration of the
+ concepts and typical usage patterns discussed above.
+
+
+6.2 'hist' trigger examples
+---------------------------
+
+ The first set of examples creates aggregations using the kmalloc
+ event. The fields that can be used for the hist trigger are listed
+ in the kmalloc event's format file:
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/format
+ name: kmalloc
+ ID: 374
+ format:
+ field:unsigned short common_type; offset:0; size:2; signed:0;
+ field:unsigned char common_flags; offset:2; size:1; signed:0;
+ field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
+ field:int common_pid; offset:4; size:4; signed:1;
+
+ field:unsigned long call_site; offset:8; size:8; signed:0;
+ field:const void * ptr; offset:16; size:8; signed:0;
+ field:size_t bytes_req; offset:24; size:8; signed:0;
+ field:size_t bytes_alloc; offset:32; size:8; signed:0;
+ field:gfp_t gfp_flags; offset:40; size:4; signed:0;
+
+ We'll start by creating a hist trigger that generates a simple table
+ that lists the total number of bytes requested for each function in
+ the kernel that made one or more calls to kmalloc:
+
+ # echo 'hist:key=call_site:val=bytes_req' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ This tells the tracing system to create a 'hist' trigger using the
+ call_site field of the kmalloc event as the key for the table, which
+ just means that each unique call_site address will have an entry
+ created for it in the table. The 'val=bytes_req' parameter tells
+ the hist trigger that for each unique entry (call_site) in the
+ table, it should keep a running total of the number of bytes
+ requested by that call_site.
+
+ We'll let it run for awhile and then dump the contents of the 'hist'
+ file in the kmalloc event's subdirectory (for readability, a number
+ of entries have been omitted):
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site:vals=bytes_req:sort=hitcount:size=2048 [active]
+
+ { call_site: 18446744072106379007 } hitcount: 1 bytes_req: 176
+ { call_site: 18446744071579557049 } hitcount: 1 bytes_req: 1024
+ { call_site: 18446744071580608289 } hitcount: 1 bytes_req: 16384
+ { call_site: 18446744071581827654 } hitcount: 1 bytes_req: 24
+ { call_site: 18446744071580700980 } hitcount: 1 bytes_req: 8
+ { call_site: 18446744071579359876 } hitcount: 1 bytes_req: 152
+ { call_site: 18446744071580795365 } hitcount: 3 bytes_req: 144
+ { call_site: 18446744071581303129 } hitcount: 3 bytes_req: 144
+ { call_site: 18446744071580713234 } hitcount: 4 bytes_req: 2560
+ { call_site: 18446744071580933750 } hitcount: 4 bytes_req: 736
+ .
+ .
+ .
+ { call_site: 18446744072106047046 } hitcount: 69 bytes_req: 5576
+ { call_site: 18446744071582116407 } hitcount: 73 bytes_req: 2336
+ { call_site: 18446744072106054684 } hitcount: 136 bytes_req: 140504
+ { call_site: 18446744072106224230 } hitcount: 136 bytes_req: 19584
+ { call_site: 18446744072106078074 } hitcount: 153 bytes_req: 2448
+ { call_site: 18446744072106062406 } hitcount: 153 bytes_req: 36720
+ { call_site: 18446744071582507929 } hitcount: 153 bytes_req: 37088
+ { call_site: 18446744072102520590 } hitcount: 273 bytes_req: 10920
+ { call_site: 18446744071582143559 } hitcount: 358 bytes_req: 716
+ { call_site: 18446744072106465852 } hitcount: 417 bytes_req: 56712
+ { call_site: 18446744072102523378 } hitcount: 485 bytes_req: 27160
+ { call_site: 18446744072099568646 } hitcount: 1676 bytes_req: 33520
+
+ Totals:
+ Hits: 4610
+ Entries: 45
+ Dropped: 0
+
+ The output displays a line for each entry, beginning with the key
+ specified in the trigger, followed by the value(s) also specified in
+ the trigger. At the beginning of the output is a line that displays
+ the trigger info, which can also be displayed by reading the
+ 'trigger' file:
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+ hist:keys=call_site:vals=bytes_req:sort=hitcount:size=2048 [active]
+
+ At the end of the output are a few lines that display the overall
+ totals for the run. The 'Hits' field shows the total number of
+ times the event trigger was hit, the 'Entries' fields shows the
+ total number of used entries in the hash table, and the 'Dropped'
+ field shows the number of hits that were dropped because the number
+ of used entries for the run exceeded the maximum number of entries
+ allowed for the table (normally 0, but if not a hint that you may
+ want to increase the size of the table using the 'size' param).
+
+ Notice in the above output that there's an extra field, 'hitcount',
+ that wasn't specified in the trigger. Also notice that in the
+ trigger info a param,'sort=hitcount', which wasn't specified in the
+ trigger either. The reason is that every trigger implicitly keeps a
+ count of the total number of hits attributed to a given entry,
+ called the 'hitcount', and that in the absence of a user-specified
+ sort param, the hitcount is used as the default sort field.
+
+ The value 'hitcount' can be used in place of an explicit value in
+ the 'values' param if you don't really need to have any particular
+ field summed and are mainly interested in hit frequencies.
+
+ To turn the hist trigger off, simply call up the trigger in command
+ history and re-execute it with a '!' prepended:
+
+ # echo '!hist:key=call_site:val=bytes_req' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ Finally, notice that the call_site as displayed in the output above
+ isn't really very useful. It's an address, but normally addresses
+ are displayed in hex. To have a numeric field displayed as hex
+ values, simply append '.hex' to the field name in the trigger:
+
+ # echo 'hist:key=call_site.hex:val=bytes_req' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.hex:vals=bytes_req:sort=hitcount:size=2048 [active]
+
+ { call_site: ffffffffa026b291 } hitcount: 1 bytes_req: 433
+ { call_site: ffffffffa07186ff } hitcount: 1 bytes_req: 176
+ { call_site: ffffffff811ae721 } hitcount: 1 bytes_req: 16384
+ { call_site: ffffffff811c5134 } hitcount: 1 bytes_req: 8
+ { call_site: ffffffffa04a9ebb } hitcount: 1 bytes_req: 511
+ { call_site: ffffffff8122e0a6 } hitcount: 1 bytes_req: 12
+ { call_site: ffffffff8107da84 } hitcount: 1 bytes_req: 152
+ { call_site: ffffffff812d8246 } hitcount: 1 bytes_req: 24
+ { call_site: ffffffff811dc1e5 } hitcount: 3 bytes_req: 144
+ { call_site: ffffffffa02515e8 } hitcount: 3 bytes_req: 648
+ { call_site: ffffffff81258159 } hitcount: 3 bytes_req: 144
+ { call_site: ffffffff811c80f4 } hitcount: 4 bytes_req: 544
+ .
+ .
+ .
+ { call_site: ffffffffa06c7646 } hitcount: 106 bytes_req: 8024
+ { call_site: ffffffffa06cb246 } hitcount: 132 bytes_req: 31680
+ { call_site: ffffffffa06cef7a } hitcount: 132 bytes_req: 2112
+ { call_site: ffffffff8137e399 } hitcount: 132 bytes_req: 23232
+ { call_site: ffffffffa06c941c } hitcount: 185 bytes_req: 171360
+ { call_site: ffffffffa06f2a66 } hitcount: 185 bytes_req: 26640
+ { call_site: ffffffffa036a70e } hitcount: 265 bytes_req: 10600
+ { call_site: ffffffff81325447 } hitcount: 292 bytes_req: 584
+ { call_site: ffffffffa072da3c } hitcount: 446 bytes_req: 60656
+ { call_site: ffffffffa036b1f2 } hitcount: 526 bytes_req: 29456
+ { call_site: ffffffffa0099c06 } hitcount: 1780 bytes_req: 35600
+
+ Totals:
+ Hits: 4775
+ Entries: 46
+ Dropped: 0
+
+ Even that's only marginally more useful - while hex values do look
+ more like addresses, what users are typically more interested in
+ when looking at text addresses are the corresponding symbols
+ instead. To have an address displayed as symbolic value instead,
+ simply append '.sym' or '.sym-offset' to the field name in the
+ trigger:
+
+ # echo 'hist:key=call_site.sym:val=bytes_req' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.sym:vals=bytes_req:sort=hitcount:size=2048 [active]
+
+ { call_site: [ffffffff810adcb9] syslog_print_all } hitcount: 1 bytes_req: 1024
+ { call_site: [ffffffff8154bc62] usb_control_msg } hitcount: 1 bytes_req: 8
+ { call_site: [ffffffffa00bf6fe] hidraw_send_report [hid] } hitcount: 1 bytes_req: 7
+ { call_site: [ffffffff8154acbe] usb_alloc_urb } hitcount: 1 bytes_req: 192
+ { call_site: [ffffffffa00bf1ca] hidraw_report_event [hid] } hitcount: 1 bytes_req: 7
+ { call_site: [ffffffff811e3a25] __seq_open_private } hitcount: 1 bytes_req: 40
+ { call_site: [ffffffff8109524a] alloc_fair_sched_group } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffff811febd5] fsnotify_alloc_group } hitcount: 2 bytes_req: 528
+ { call_site: [ffffffff81440f58] __tty_buffer_request_room } hitcount: 2 bytes_req: 2624
+ { call_site: [ffffffff81200ba6] inotify_new_group } hitcount: 2 bytes_req: 96
+ { call_site: [ffffffffa05e19af] ieee80211_start_tx_ba_session [mac80211] } hitcount: 2 bytes_req: 464
+ { call_site: [ffffffff81672406] tcp_get_metrics } hitcount: 2 bytes_req: 304
+ { call_site: [ffffffff81097ec2] alloc_rt_sched_group } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffff81089b05] sched_create_group } hitcount: 2 bytes_req: 1424
+ .
+ .
+ .
+ { call_site: [ffffffffa04a580c] intel_crtc_page_flip [i915] } hitcount: 1185 bytes_req: 123240
+ { call_site: [ffffffffa0287592] drm_mode_page_flip_ioctl [drm] } hitcount: 1185 bytes_req: 104280
+ { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state [i915] } hitcount: 1402 bytes_req: 190672
+ { call_site: [ffffffff812891ca] ext4_find_extent } hitcount: 1518 bytes_req: 146208
+ { call_site: [ffffffffa029070e] drm_vma_node_allow [drm] } hitcount: 1746 bytes_req: 69840
+ { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 2021 bytes_req: 792312
+ { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc [drm] } hitcount: 2592 bytes_req: 145152
+ { call_site: [ffffffffa0489a66] intel_ring_begin [i915] } hitcount: 2629 bytes_req: 378576
+ { call_site: [ffffffffa046041c] i915_gem_execbuffer2 [i915] } hitcount: 2629 bytes_req: 3783248
+ { call_site: [ffffffff81325607] apparmor_file_alloc_security } hitcount: 5192 bytes_req: 10384
+ { call_site: [ffffffffa00b7c06] hid_report_raw_event [hid] } hitcount: 5529 bytes_req: 110584
+ { call_site: [ffffffff8131ebf7] aa_alloc_task_context } hitcount: 21943 bytes_req: 702176
+ { call_site: [ffffffff8125847d] ext4_htree_store_dirent } hitcount: 55759 bytes_req: 5074265
+
+ Totals:
+ Hits: 109928
+ Entries: 71
+ Dropped: 0
+
+ Because the default sort key above is 'hitcount', the above shows a
+ the list of call_sites by increasing hitcount, so that at the bottom
+ we see the functions that made the most kmalloc calls during the
+ run. If instead we we wanted to see the top kmalloc callers in
+ terms of the number of bytes requested rather than the number of
+ calls, and we wanted the top caller to appear at the top, we can use
+ the 'sort' param, along with the 'descending' modifier:
+
+ # echo 'hist:key=call_site.sym:val=bytes_req:sort=bytes_req.descending' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.sym:vals=bytes_req:sort=bytes_req.descending:size=2048 [active]
+
+ { call_site: [ffffffffa046041c] i915_gem_execbuffer2 [i915] } hitcount: 2186 bytes_req: 3397464
+ { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 1790 bytes_req: 712176
+ { call_site: [ffffffff8125847d] ext4_htree_store_dirent } hitcount: 8132 bytes_req: 513135
+ { call_site: [ffffffff811e2a1b] seq_buf_alloc } hitcount: 106 bytes_req: 440128
+ { call_site: [ffffffffa0489a66] intel_ring_begin [i915] } hitcount: 2186 bytes_req: 314784
+ { call_site: [ffffffff812891ca] ext4_find_extent } hitcount: 2174 bytes_req: 208992
+ { call_site: [ffffffff811ae8e1] __kmalloc } hitcount: 8 bytes_req: 131072
+ { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state [i915] } hitcount: 859 bytes_req: 116824
+ { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc [drm] } hitcount: 1834 bytes_req: 102704
+ { call_site: [ffffffffa04a580c] intel_crtc_page_flip [i915] } hitcount: 972 bytes_req: 101088
+ { call_site: [ffffffffa0287592] drm_mode_page_flip_ioctl [drm] } hitcount: 972 bytes_req: 85536
+ { call_site: [ffffffffa00b7c06] hid_report_raw_event [hid] } hitcount: 3333 bytes_req: 66664
+ { call_site: [ffffffff8137e559] sg_kmalloc } hitcount: 209 bytes_req: 61632
+ .
+ .
+ .
+ { call_site: [ffffffff81095225] alloc_fair_sched_group } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffff81097ec2] alloc_rt_sched_group } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffff812d8406] copy_semundo } hitcount: 2 bytes_req: 48
+ { call_site: [ffffffff81200ba6] inotify_new_group } hitcount: 1 bytes_req: 48
+ { call_site: [ffffffffa027121a] drm_getmagic [drm] } hitcount: 1 bytes_req: 48
+ { call_site: [ffffffff811e3a25] __seq_open_private } hitcount: 1 bytes_req: 40
+ { call_site: [ffffffff811c52f4] bprm_change_interp } hitcount: 2 bytes_req: 16
+ { call_site: [ffffffff8154bc62] usb_control_msg } hitcount: 1 bytes_req: 8
+ { call_site: [ffffffffa00bf1ca] hidraw_report_event [hid] } hitcount: 1 bytes_req: 7
+ { call_site: [ffffffffa00bf6fe] hidraw_send_report [hid] } hitcount: 1 bytes_req: 7
+
+ Totals:
+ Hits: 32133
+ Entries: 81
+ Dropped: 0
+
+ To display the offset and size information in addition to the symbol
+ name, just use 'sym-offset' instead:
+
+ # echo 'hist:key=call_site.sym-offset:val=bytes_req:sort=bytes_req.descending' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.sym-offset:vals=bytes_req:sort=bytes_req.descending:size=2048 [active]
+
+ { call_site: [ffffffffa046041c] i915_gem_execbuffer2+0x6c/0x2c0 [i915] } hitcount: 4569 bytes_req: 3163720
+ { call_site: [ffffffffa0489a66] intel_ring_begin+0xc6/0x1f0 [i915] } hitcount: 4569 bytes_req: 657936
+ { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23+0x694/0x1020 [i915] } hitcount: 1519 bytes_req: 472936
+ { call_site: [ffffffffa045e646] i915_gem_do_execbuffer.isra.23+0x516/0x1020 [i915] } hitcount: 3050 bytes_req: 211832
+ { call_site: [ffffffff811e2a1b] seq_buf_alloc+0x1b/0x50 } hitcount: 34 bytes_req: 148384
+ { call_site: [ffffffffa04a580c] intel_crtc_page_flip+0xbc/0x870 [i915] } hitcount: 1385 bytes_req: 144040
+ { call_site: [ffffffff811ae8e1] __kmalloc+0x191/0x1b0 } hitcount: 8 bytes_req: 131072
+ { call_site: [ffffffffa0287592] drm_mode_page_flip_ioctl+0x282/0x360 [drm] } hitcount: 1385 bytes_req: 121880
+ { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc+0x32/0x100 [drm] } hitcount: 1848 bytes_req: 103488
+ { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state+0x2c/0xa0 [i915] } hitcount: 461 bytes_req: 62696
+ { call_site: [ffffffffa029070e] drm_vma_node_allow+0x2e/0xd0 [drm] } hitcount: 1541 bytes_req: 61640
+ { call_site: [ffffffff815f8d7b] sk_prot_alloc+0xcb/0x1b0 } hitcount: 57 bytes_req: 57456
+ .
+ .
+ .
+ { call_site: [ffffffff8109524a] alloc_fair_sched_group+0x5a/0x1a0 } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffffa027b921] drm_vm_open_locked+0x31/0xa0 [drm] } hitcount: 3 bytes_req: 96
+ { call_site: [ffffffff8122e266] proc_self_follow_link+0x76/0xb0 } hitcount: 8 bytes_req: 96
+ { call_site: [ffffffff81213e80] load_elf_binary+0x240/0x1650 } hitcount: 3 bytes_req: 84
+ { call_site: [ffffffff8154bc62] usb_control_msg+0x42/0x110 } hitcount: 1 bytes_req: 8
+ { call_site: [ffffffffa00bf6fe] hidraw_send_report+0x7e/0x1a0 [hid] } hitcount: 1 bytes_req: 7
+ { call_site: [ffffffffa00bf1ca] hidraw_report_event+0x8a/0x120 [hid] } hitcount: 1 bytes_req: 7
+
+ Totals:
+ Hits: 26098
+ Entries: 64
+ Dropped: 0
+
+ We can also add multiple fields to the 'values' param. For example,
+ we might want to see the total number of bytes allocated alongside
+ bytes requested, and display the result sorted by bytes allocated in
+ a descending order:
+
+ # echo 'hist:keys=call_site.sym:values=bytes_req,bytes_alloc:sort=bytes_alloc.descending' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.sym:vals=bytes_req,bytes_alloc:sort=bytes_alloc.descending:size=2048 [active]
+
+ { call_site: [ffffffffa046041c] i915_gem_execbuffer2 [i915] } hitcount: 7403 bytes_req: 4084360 bytes_alloc: 5958016
+ { call_site: [ffffffff811e2a1b] seq_buf_alloc } hitcount: 541 bytes_req: 2213968 bytes_alloc: 2228224
+ { call_site: [ffffffffa0489a66] intel_ring_begin [i915] } hitcount: 7404 bytes_req: 1066176 bytes_alloc: 1421568
+ { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 1565 bytes_req: 557368 bytes_alloc: 1037760
+ { call_site: [ffffffff8125847d] ext4_htree_store_dirent } hitcount: 9557 bytes_req: 595778 bytes_alloc: 695744
+ { call_site: [ffffffffa045e646] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 5839 bytes_req: 430680 bytes_alloc: 470400
+ { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state [i915] } hitcount: 2388 bytes_req: 324768 bytes_alloc: 458496
+ { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc [drm] } hitcount: 3911 bytes_req: 219016 bytes_alloc: 250304
+ { call_site: [ffffffff815f8d7b] sk_prot_alloc } hitcount: 235 bytes_req: 236880 bytes_alloc: 240640
+ { call_site: [ffffffff8137e559] sg_kmalloc } hitcount: 557 bytes_req: 169024 bytes_alloc: 221760
+ { call_site: [ffffffffa00b7c06] hid_report_raw_event [hid] } hitcount: 9378 bytes_req: 187548 bytes_alloc: 206312
+ { call_site: [ffffffffa04a580c] intel_crtc_page_flip [i915] } hitcount: 1519 bytes_req: 157976 bytes_alloc: 194432
+ .
+ .
+ .
+ { call_site: [ffffffff8109bd3b] sched_autogroup_create_attach } hitcount: 2 bytes_req: 144 bytes_alloc: 192
+ { call_site: [ffffffff81097ee8] alloc_rt_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128
+ { call_site: [ffffffff8109524a] alloc_fair_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128
+ { call_site: [ffffffff81095225] alloc_fair_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128
+ { call_site: [ffffffff81097ec2] alloc_rt_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128
+ { call_site: [ffffffff81213e80] load_elf_binary } hitcount: 3 bytes_req: 84 bytes_alloc: 96
+ { call_site: [ffffffff81079a2e] kthread_create_on_node } hitcount: 1 bytes_req: 56 bytes_alloc: 64
+ { call_site: [ffffffffa00bf6fe] hidraw_send_report [hid] } hitcount: 1 bytes_req: 7 bytes_alloc: 8
+ { call_site: [ffffffff8154bc62] usb_control_msg } hitcount: 1 bytes_req: 8 bytes_alloc: 8
+ { call_site: [ffffffffa00bf1ca] hidraw_report_event [hid] } hitcount: 1 bytes_req: 7 bytes_alloc: 8
+
+ Totals:
+ Hits: 66598
+ Entries: 65
+ Dropped: 0
+
+ Finally, to finish off our kmalloc example, instead of simply having
+ the hist trigger display symbolic call_sites, we can have the hist
+ trigger additionally display the complete set of kernel stack traces
+ that led to each call_sites. To do that, we simply use the special
+ value 'stacktrace' for the key param:
+
+ # echo 'hist:keys=stacktrace:values=bytes_req,bytes_alloc:sort=bytes_alloc' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ The above trigger will use the kernel stack trace in effect when an
+ event is triggered as the key for the hash table. This allows the
+ enumeration of every kernel callpath that led up to a particular
+ event, along with a running total of any of the event fields for
+ that event. Here we tally bytes requested and bytes allocated for
+ every callpath in the system that led up to a kmalloc (in this case
+ every callpath to a kmalloc for a kernel compile):
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=stacktrace:vals=bytes_req,bytes_alloc:sort=bytes_alloc:size=2048 [active]
+
+ { stacktrace:
+ __kmalloc_track_caller+0x10b/0x1a0
+ kmemdup+0x20/0x50
+ hidraw_report_event+0x8a/0x120 [hid]
+ hid_report_raw_event+0x3ea/0x440 [hid]
+ hid_input_report+0x112/0x190 [hid]
+ hid_irq_in+0xc2/0x260 [usbhid]
+ __usb_hcd_giveback_urb+0x72/0x120
+ usb_giveback_urb_bh+0x9e/0xe0
+ tasklet_hi_action+0xf8/0x100
+ __do_softirq+0x114/0x2c0
+ irq_exit+0xa5/0xb0
+ do_IRQ+0x5a/0xf0
+ ret_from_intr+0x0/0x30
+ cpuidle_enter+0x17/0x20
+ cpu_startup_entry+0x315/0x3e0
+ rest_init+0x7c/0x80
+ } hitcount: 3 bytes_req: 21 bytes_alloc: 24
+ { stacktrace:
+ __kmalloc_track_caller+0x10b/0x1a0
+ kmemdup+0x20/0x50
+ hidraw_report_event+0x8a/0x120 [hid]
+ hid_report_raw_event+0x3ea/0x440 [hid]
+ hid_input_report+0x112/0x190 [hid]
+ hid_irq_in+0xc2/0x260 [usbhid]
+ __usb_hcd_giveback_urb+0x72/0x120
+ usb_giveback_urb_bh+0x9e/0xe0
+ tasklet_hi_action+0xf8/0x100
+ __do_softirq+0x114/0x2c0
+ irq_exit+0xa5/0xb0
+ do_IRQ+0x5a/0xf0
+ ret_from_intr+0x0/0x30
+ } hitcount: 3 bytes_req: 21 bytes_alloc: 24
+ { stacktrace:
+ kmem_cache_alloc_trace+0xeb/0x150
+ aa_alloc_task_context+0x27/0x40
+ apparmor_cred_prepare+0x1f/0x50
+ security_prepare_creds+0x16/0x20
+ prepare_creds+0xdf/0x1a0
+ SyS_capset+0xb5/0x200
+ system_call_fastpath+0x12/0x6a
+ } hitcount: 1 bytes_req: 32 bytes_alloc: 32
+ .
+ .
+ .
+ { stacktrace:
+ __kmalloc+0x11b/0x1b0
+ i915_gem_execbuffer2+0x6c/0x2c0 [i915]
+ drm_ioctl+0x349/0x670 [drm]
+ do_vfs_ioctl+0x2f0/0x4f0
+ SyS_ioctl+0x81/0xa0
+ system_call_fastpath+0x12/0x6a
+ } hitcount: 17726 bytes_req: 13944120 bytes_alloc: 19593808
+ { stacktrace:
+ __kmalloc+0x11b/0x1b0
+ load_elf_phdrs+0x76/0xa0
+ load_elf_binary+0x102/0x1650
+ search_binary_handler+0x97/0x1d0
+ do_execveat_common.isra.34+0x551/0x6e0
+ SyS_execve+0x3a/0x50
+ return_from_execve+0x0/0x23
+ } hitcount: 33348 bytes_req: 17152128 bytes_alloc: 20226048
+ { stacktrace:
+ kmem_cache_alloc_trace+0xeb/0x150
+ apparmor_file_alloc_security+0x27/0x40
+ security_file_alloc+0x16/0x20
+ get_empty_filp+0x93/0x1c0
+ path_openat+0x31/0x5f0
+ do_filp_open+0x3a/0x90
+ do_sys_open+0x128/0x220
+ SyS_open+0x1e/0x20
+ system_call_fastpath+0x12/0x6a
+ } hitcount: 4766422 bytes_req: 9532844 bytes_alloc: 38131376
+ { stacktrace:
+ __kmalloc+0x11b/0x1b0
+ seq_buf_alloc+0x1b/0x50
+ seq_read+0x2cc/0x370
+ proc_reg_read+0x3d/0x80
+ __vfs_read+0x28/0xe0
+ vfs_read+0x86/0x140
+ SyS_read+0x46/0xb0
+ system_call_fastpath+0x12/0x6a
+ } hitcount: 19133 bytes_req: 78368768 bytes_alloc: 78368768
+
+ Totals:
+ Hits: 6085872
+ Entries: 253
+ Dropped: 0
+
+ If you key a hist trigger on common_pid, in order for example to
+ gather and display sorted totals for each process, you can use the
+ special .execname modifier to display the executable names for the
+ processes in the table rather than raw pids. The example below
+ keeps a per-process sum of total bytes read:
+
+ # echo 'hist:key=common_pid.execname:val=count:sort=count.descending' > \
+ /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
+
+ # cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/hist
+ # trigger info: hist:keys=common_pid.execname:vals=count:sort=count.descending:size=2048 [active]
+
+ { common_pid: gnome-terminal [ 3196] } hitcount: 280 count: 1093512
+ { common_pid: Xorg [ 1309] } hitcount: 525 count: 256640
+ { common_pid: compiz [ 2889] } hitcount: 59 count: 254400
+ { common_pid: bash [ 8710] } hitcount: 3 count: 66369
+ { common_pid: dbus-daemon-lau [ 8703] } hitcount: 49 count: 47739
+ { common_pid: irqbalance [ 1252] } hitcount: 27 count: 27648
+ { common_pid: 01ifupdown [ 8705] } hitcount: 3 count: 17216
+ { common_pid: dbus-daemon [ 772] } hitcount: 10 count: 12396
+ { common_pid: Socket Thread [ 8342] } hitcount: 11 count: 11264
+ { common_pid: nm-dhcp-client. [ 8701] } hitcount: 6 count: 7424
+ { common_pid: gmain [ 1315] } hitcount: 18 count: 6336
+ .
+ .
+ .
+ { common_pid: postgres [ 1892] } hitcount: 2 count: 32
+ { common_pid: postgres [ 1891] } hitcount: 2 count: 32
+ { common_pid: gmain [ 8704] } hitcount: 2 count: 32
+ { common_pid: upstart-dbus-br [ 2740] } hitcount: 21 count: 21
+ { common_pid: nm-dispatcher.a [ 8696] } hitcount: 1 count: 16
+ { common_pid: indicator-datet [ 2904] } hitcount: 1 count: 16
+ { common_pid: gdbus [ 2998] } hitcount: 1 count: 16
+ { common_pid: rtkit-daemon [ 2052] } hitcount: 1 count: 8
+ { common_pid: init [ 1] } hitcount: 2 count: 2
+
+ Totals:
+ Hits: 2116
+ Entries: 51
+ Dropped: 0
+
+ Similarly, if you key a hist trigger on syscall id, for example to
+ gather and display a list of systemwide syscall hits, you can use
+ the special .syscall modifier to display the syscall names rather
+ than raw ids. The example below keeps a running total of syscall
+ counts for the system during the run:
+
+ # echo 'hist:key=id.syscall:val=hitcount' > \
+ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
+
+ # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist
+ # trigger info: hist:keys=id.syscall:vals=hitcount:sort=hitcount:size=2048 [active]
+
+ { id: sys_fsync [ 74] } hitcount: 1
+ { id: sys_newuname [ 63] } hitcount: 1
+ { id: sys_prctl [157] } hitcount: 1
+ { id: sys_statfs [137] } hitcount: 1
+ { id: sys_symlink [ 88] } hitcount: 1
+ { id: sys_sendmmsg [307] } hitcount: 1
+ { id: sys_semctl [ 66] } hitcount: 1
+ { id: sys_readlink [ 89] } hitcount: 3
+ { id: sys_bind [ 49] } hitcount: 3
+ { id: sys_getsockname [ 51] } hitcount: 3
+ { id: sys_unlink [ 87] } hitcount: 3
+ { id: sys_rename [ 82] } hitcount: 4
+ { id: unknown_syscall [ 58] } hitcount: 4
+ { id: sys_connect [ 42] } hitcount: 4
+ { id: sys_getpid [ 39] } hitcount: 4
+ .
+ .
+ .
+ { id: sys_rt_sigprocmask [ 14] } hitcount: 952
+ { id: sys_futex [202] } hitcount: 1534
+ { id: sys_write [ 1] } hitcount: 2689
+ { id: sys_setitimer [ 38] } hitcount: 2797
+ { id: sys_read [ 0] } hitcount: 3202
+ { id: sys_select [ 23] } hitcount: 3773
+ { id: sys_writev [ 20] } hitcount: 4531
+ { id: sys_poll [ 7] } hitcount: 8314
+ { id: sys_recvmsg [ 47] } hitcount: 13738
+ { id: sys_ioctl [ 16] } hitcount: 21843
+
+ Totals:
+ Hits: 67612
+ Entries: 72
+ Dropped: 0
+
+ The syscall counts above provide a rough overall picture of system
+ call activity on the system; we can see for example that the most
+ popular system call on this system was the 'sys_ioctl' system call.
+
+ We can use 'compound' keys to refine that number and provide some
+ further insight as to which processes exactly contribute to the
+ overall ioctl count.
+
+ The command below keeps a hitcount for every unique combination of
+ system call id and pid - the end result is essentially a table
+ that keeps a per-pid sum of system call hits. The results are
+ sorted using the system call id as the primary key, and the
+ hitcount sum as the secondary key:
+
+ # echo 'hist:key=id.syscall,common_pid.execname:val=hitcount:sort=id,hitcount' > \
+ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
+
+ # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist
+ # trigger info: hist:keys=id.syscall,common_pid.execname:vals=hitcount:sort=id.syscall,hitcount:size=2048 [active]
+
+ { id: sys_read [ 0], common_pid: rtkit-daemon [ 1877] } hitcount: 1
+ { id: sys_read [ 0], common_pid: gdbus [ 2976] } hitcount: 1
+ { id: sys_read [ 0], common_pid: console-kit-dae [ 3400] } hitcount: 1
+ { id: sys_read [ 0], common_pid: postgres [ 1865] } hitcount: 1
+ { id: sys_read [ 0], common_pid: deja-dup-monito [ 3543] } hitcount: 2
+ { id: sys_read [ 0], common_pid: NetworkManager [ 890] } hitcount: 2
+ { id: sys_read [ 0], common_pid: evolution-calen [ 3048] } hitcount: 2
+ { id: sys_read [ 0], common_pid: postgres [ 1864] } hitcount: 2
+ { id: sys_read [ 0], common_pid: nm-applet [ 3022] } hitcount: 2
+ { id: sys_read [ 0], common_pid: whoopsie [ 1212] } hitcount: 2
+ .
+ .
+ .
+ { id: sys_ioctl [ 16], common_pid: bash [ 8479] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: bash [ 3472] } hitcount: 12
+ { id: sys_ioctl [ 16], common_pid: gnome-terminal [ 3199] } hitcount: 16
+ { id: sys_ioctl [ 16], common_pid: Xorg [ 1267] } hitcount: 1808
+ { id: sys_ioctl [ 16], common_pid: compiz [ 2994] } hitcount: 5580
+ .
+ .
+ .
+ { id: sys_waitid [247], common_pid: upstart-dbus-br [ 2690] } hitcount: 3
+ { id: sys_waitid [247], common_pid: upstart-dbus-br [ 2688] } hitcount: 16
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 975] } hitcount: 2
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 3204] } hitcount: 4
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 2888] } hitcount: 4
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 3003] } hitcount: 4
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 2873] } hitcount: 4
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 3196] } hitcount: 6
+ { id: sys_openat [257], common_pid: java [ 2623] } hitcount: 2
+ { id: sys_eventfd2 [290], common_pid: ibus-ui-gtk3 [ 2760] } hitcount: 4
+ { id: sys_eventfd2 [290], common_pid: compiz [ 2994] } hitcount: 6
+
+ Totals:
+ Hits: 31536
+ Entries: 323
+ Dropped: 0
+
+ The above list does give us a breakdown of the ioctl syscall by
+ pid, but it also gives us quite a bit more than that, which we
+ don't really care about at the moment. Since we know the syscall
+ id for sys_ioctl (16, displayed next to the sys_ioctl name), we
+ can use that to filter out all the other syscalls:
+
+ # echo 'hist:key=id.syscall,common_pid.execname:val=hitcount:sort=id,hitcount if id == 16' > \
+ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
+
+ # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist
+ # trigger info: hist:keys=id.syscall,common_pid.execname:vals=hitcount:sort=id.syscall,hitcount:size=2048 if id == 16 [active]
+
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2769] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: evolution-addre [ 8571] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 3003] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2781] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2829] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: bash [ 8726] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: bash [ 8508] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2970] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2768] } hitcount: 1
+ .
+ .
+ .
+ { id: sys_ioctl [ 16], common_pid: pool [ 8559] } hitcount: 45
+ { id: sys_ioctl [ 16], common_pid: pool [ 8555] } hitcount: 48
+ { id: sys_ioctl [ 16], common_pid: pool [ 8551] } hitcount: 48
+ { id: sys_ioctl [ 16], common_pid: avahi-daemon [ 896] } hitcount: 66
+ { id: sys_ioctl [ 16], common_pid: Xorg [ 1267] } hitcount: 26674
+ { id: sys_ioctl [ 16], common_pid: compiz [ 2994] } hitcount: 73443
+
+ Totals:
+ Hits: 101162
+ Entries: 103
+ Dropped: 0
+
+ The above output shows that 'compiz' and 'Xorg' are far and away
+ the heaviest ioctl callers (do the really need to do so much of
+ that?).
+
+ The compound key examples used a key and a sum value (hitcount) to
+ sort the output, but we can just as easily use two keys instead.
+ Here's an example where we use a compound key composed of the the
+ common_pid and size event fields. Sorting with pid as the primary
+ key and 'size' as the secondary key allows us to display an
+ ordered summary of the recvfrom sizes, with counts, received by
+ each process:
+
+ # echo 'hist:key=common_pid.execname,size:val=hitcount:sort=common_pid,size' > \
+ /sys/kernel/debug/tracing/events/syscalls/sys_enter_recvfrom/trigger
+
+ # cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_recvfrom/hist
+ # trigger info: hist:keys=common_pid.execname,size:vals=hitcount:sort=common_pid.execname,size:size=2048 [active]
+
+ { common_pid: smbd [ 784], size: 4 } hitcount: 1
+ { common_pid: dnsmasq [ 1412], size: 4096 } hitcount: 672
+ { common_pid: postgres [ 1796], size: 1000 } hitcount: 6
+ { common_pid: postgres [ 1867], size: 1000 } hitcount: 10
+ { common_pid: bamfdaemon [ 2787], size: 28 } hitcount: 2
+ { common_pid: bamfdaemon [ 2787], size: 14360 } hitcount: 1
+ { common_pid: compiz [ 2994], size: 8 } hitcount: 1
+ { common_pid: compiz [ 2994], size: 20 } hitcount: 11
+ { common_pid: gnome-terminal [ 3199], size: 4 } hitcount: 2
+ { common_pid: firefox [ 8817], size: 4 } hitcount: 1
+ { common_pid: firefox [ 8817], size: 8 } hitcount: 5
+ { common_pid: firefox [ 8817], size: 588 } hitcount: 2
+ { common_pid: firefox [ 8817], size: 628 } hitcount: 1
+ { common_pid: firefox [ 8817], size: 6944 } hitcount: 1
+ { common_pid: firefox [ 8817], size: 408880 } hitcount: 2
+ { common_pid: firefox [ 8822], size: 8 } hitcount: 2
+ { common_pid: firefox [ 8822], size: 160 } hitcount: 2
+ { common_pid: firefox [ 8822], size: 320 } hitcount: 2
+ { common_pid: firefox [ 8822], size: 352 } hitcount: 1
+ .
+ .
+ .
+ { common_pid: pool [ 8923], size: 1960 } hitcount: 10
+ { common_pid: pool [ 8923], size: 2048 } hitcount: 10
+ { common_pid: pool [ 8924], size: 1960 } hitcount: 10
+ { common_pid: pool [ 8924], size: 2048 } hitcount: 10
+ { common_pid: pool [ 8928], size: 1964 } hitcount: 4
+ { common_pid: pool [ 8928], size: 1965 } hitcount: 2
+ { common_pid: pool [ 8928], size: 2048 } hitcount: 6
+ { common_pid: pool [ 8929], size: 1982 } hitcount: 1
+ { common_pid: pool [ 8929], size: 2048 } hitcount: 1
+
+ Totals:
+ Hits: 2016
+ Entries: 224
+ Dropped: 0
+
+ The above example also illustrates the fact that although a compound
+ key is treated as a single entity for hashing purposes, the sub-keys
+ it's composed of can be accessed independently.
+
+ The next example uses a string field as the hash key and
+ demonstrates how you can manually pause and continue a hist trigger.
+ In this example, we'll aggregate fork counts and don't expect a
+ large number of entries in the hash table, so we'll drop it to a
+ much smaller number, say 256:
+
+ # echo 'hist:key=child_comm:val=hitcount:size=256' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist
+ # trigger info: hist:keys=child_comm:vals=hitcount:sort=hitcount:size=256 [active]
+
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: ibus-daemon } hitcount: 1
+ { child_comm: whoopsie } hitcount: 1
+ { child_comm: smbd } hitcount: 1
+ { child_comm: gdbus } hitcount: 1
+ { child_comm: kthreadd } hitcount: 1
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: evolution-alarm } hitcount: 2
+ { child_comm: Socket Thread } hitcount: 2
+ { child_comm: postgres } hitcount: 2
+ { child_comm: bash } hitcount: 3
+ { child_comm: compiz } hitcount: 3
+ { child_comm: evolution-sourc } hitcount: 4
+ { child_comm: dhclient } hitcount: 4
+ { child_comm: pool } hitcount: 5
+ { child_comm: nm-dispatcher.a } hitcount: 8
+ { child_comm: firefox } hitcount: 8
+ { child_comm: dbus-daemon } hitcount: 8
+ { child_comm: glib-pacrunner } hitcount: 10
+ { child_comm: evolution } hitcount: 23
+
+ Totals:
+ Hits: 89
+ Entries: 20
+ Dropped: 0
+
+ If we want to pause the hist trigger, we can simply append :pause to
+ the command that started the trigger. Notice that the trigger info
+ displays as [paused]:
+
+ # echo 'hist:key=child_comm:val=hitcount:size=256:pause' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist
+ # trigger info: hist:keys=child_comm:vals=hitcount:sort=hitcount:size=256 [paused]
+
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: kthreadd } hitcount: 1
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: gdbus } hitcount: 1
+ { child_comm: ibus-daemon } hitcount: 1
+ { child_comm: Socket Thread } hitcount: 2
+ { child_comm: evolution-alarm } hitcount: 2
+ { child_comm: smbd } hitcount: 2
+ { child_comm: bash } hitcount: 3
+ { child_comm: whoopsie } hitcount: 3
+ { child_comm: compiz } hitcount: 3
+ { child_comm: evolution-sourc } hitcount: 4
+ { child_comm: pool } hitcount: 5
+ { child_comm: postgres } hitcount: 6
+ { child_comm: firefox } hitcount: 8
+ { child_comm: dhclient } hitcount: 10
+ { child_comm: emacs } hitcount: 12
+ { child_comm: dbus-daemon } hitcount: 20
+ { child_comm: nm-dispatcher.a } hitcount: 20
+ { child_comm: evolution } hitcount: 35
+ { child_comm: glib-pacrunner } hitcount: 59
+
+ Totals:
+ Hits: 199
+ Entries: 21
+ Dropped: 0
+
+ To manually continue having the trigger aggregate events, append
+ :cont instead. Notice that the trigger info displays as [active]
+ again, and the data has changed:
+
+ # echo 'hist:key=child_comm:val=hitcount:size=256:cont' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist
+ # trigger info: hist:keys=child_comm:vals=hitcount:sort=hitcount:size=256 [active]
+
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: kthreadd } hitcount: 1
+ { child_comm: gdbus } hitcount: 1
+ { child_comm: ibus-daemon } hitcount: 1
+ { child_comm: Socket Thread } hitcount: 2
+ { child_comm: evolution-alarm } hitcount: 2
+ { child_comm: smbd } hitcount: 2
+ { child_comm: whoopsie } hitcount: 3
+ { child_comm: compiz } hitcount: 3
+ { child_comm: evolution-sourc } hitcount: 4
+ { child_comm: bash } hitcount: 5
+ { child_comm: pool } hitcount: 5
+ { child_comm: postgres } hitcount: 6
+ { child_comm: firefox } hitcount: 8
+ { child_comm: dhclient } hitcount: 11
+ { child_comm: emacs } hitcount: 12
+ { child_comm: dbus-daemon } hitcount: 22
+ { child_comm: nm-dispatcher.a } hitcount: 22
+ { child_comm: evolution } hitcount: 35
+ { child_comm: glib-pacrunner } hitcount: 59
+
+ Totals:
+ Hits: 206
+ Entries: 21
+ Dropped: 0
+
+ The previous example showed how to start and stop a hist trigger by
+ appending 'pause' and 'continue' to the hist trigger command. A
+ hist trigger can also be started in a paused state by initially
+ starting the trigger with ':pause' appended. This allows you to
+ start the trigger only when you're ready to start collecting data
+ and not before. For example, start the trigger in a paused state,
+ then unpause it and do something you want to measure, then pause the
+ trigger when done.
+
+ Of course, doing this manually can be difficult and error-prone, but
+ it is possible to automatically start and stop a hist trigger based
+ on some condition, via the enable_hist and disable_hist triggers.
+
+ For example, suppose we wanted to take a look at the relative
+ weights in terms of skb length for each callpath that leads to a
+ netif_receieve_skb event when downloading a decent-sized file using
+ wget.
+
+ First we set up an initially paused stacktrace trigger on the
+ netif_receive_skb event:
+
+ # echo 'hist:key=stacktrace:vals=len:pause' > \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+
+ Next, we set up an 'enable_hist' trigger on the sched_process_exec
+ event, with an 'if filename==/usr/bin/wget' filter. The effect of
+ this new trigger is that it will 'unpause' the hist trigger we just
+ set up on netif_receive_skb if and only if it sees a
+ sched_process_exec event with a filename of '/usr/bin/wget'. When
+ that happens, all netif_receive_skb events are aggregated into a
+ hash table keyed on stacktrace:
+
+ # echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
+
+ The aggregation continues until the netif_receive_skb is paused
+ again, which is what the following disable_hist event does by
+ creating a similar setup on the sched_process_exit event, using the
+ filter 'comm==wget':
+
+ # echo 'disable_hist:net:netif_receive_skb if comm==wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
+
+ Whenever a process exits and the comm field of the disable_hist
+ trigger filter matches 'comm==wget', the netif_receive_skb hist
+ trigger is disabled.
+
+ The overall effect is that netif_received_skb events are aggregated
+ into the hash table for only the duration of the wget. Executing a
+ wget command and then listing the 'hist' file will display the
+ output generated by the wget command:
+
+ $ wget https://www.kernel.org/pub/linux/kernel/v3.x/patch-3.19.xz
+
+ # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist
+ # trigger info: hist:keys=stacktrace:vals=len:sort=hitcount:size=2048 [paused]
+
+ { stacktrace:
+ __netif_receive_skb_core+0x46d/0x990
+ __netif_receive_skb+0x18/0x60
+ netif_receive_skb_internal+0x23/0x90
+ napi_gro_receive+0xc8/0x100
+ ieee80211_deliver_skb+0xd6/0x270 [mac80211]
+ ieee80211_rx_handlers+0xccf/0x22f0 [mac80211]
+ ieee80211_prepare_and_rx_handle+0x4e7/0xc40 [mac80211]
+ ieee80211_rx+0x31d/0x900 [mac80211]
+ iwlagn_rx_reply_rx+0x3db/0x6f0 [iwldvm]
+ iwl_rx_dispatch+0x8e/0xf0 [iwldvm]
+ iwl_pcie_irq_handler+0xe3c/0x12f0 [iwlwifi]
+ irq_thread_fn+0x20/0x50
+ irq_thread+0x11f/0x150
+ kthread+0xd2/0xf0
+ ret_from_fork+0x42/0x70
+ } hitcount: 85 len: 28884
+ { stacktrace:
+ __netif_receive_skb_core+0x46d/0x990
+ __netif_receive_skb+0x18/0x60
+ netif_receive_skb_internal+0x23/0x90
+ napi_gro_complete+0xa4/0xe0
+ dev_gro_receive+0x23a/0x360
+ napi_gro_receive+0x30/0x100
+ ieee80211_deliver_skb+0xd6/0x270 [mac80211]
+ ieee80211_rx_handlers+0xccf/0x22f0 [mac80211]
+ ieee80211_prepare_and_rx_handle+0x4e7/0xc40 [mac80211]
+ ieee80211_rx+0x31d/0x900 [mac80211]
+ iwlagn_rx_reply_rx+0x3db/0x6f0 [iwldvm]
+ iwl_rx_dispatch+0x8e/0xf0 [iwldvm]
+ iwl_pcie_irq_handler+0xe3c/0x12f0 [iwlwifi]
+ irq_thread_fn+0x20/0x50
+ irq_thread+0x11f/0x150
+ kthread+0xd2/0xf0
+ } hitcount: 98 len: 664329
+ { stacktrace:
+ __netif_receive_skb_core+0x46d/0x990
+ __netif_receive_skb+0x18/0x60
+ process_backlog+0xa8/0x150
+ net_rx_action+0x15d/0x340
+ __do_softirq+0x114/0x2c0
+ do_softirq_own_stack+0x1c/0x30
+ do_softirq+0x65/0x70
+ __local_bh_enable_ip+0xb5/0xc0
+ ip_finish_output+0x1f4/0x840
+ ip_output+0x6b/0xc0
+ ip_local_out_sk+0x31/0x40
+ ip_send_skb+0x1a/0x50
+ udp_send_skb+0x173/0x2a0
+ udp_sendmsg+0x2bf/0x9f0
+ inet_sendmsg+0x64/0xa0
+ sock_sendmsg+0x3d/0x50
+ } hitcount: 115 len: 13030
+ { stacktrace:
+ __netif_receive_skb_core+0x46d/0x990
+ __netif_receive_skb+0x18/0x60
+ netif_receive_skb_internal+0x23/0x90
+ napi_gro_complete+0xa4/0xe0
+ napi_gro_flush+0x6d/0x90
+ iwl_pcie_irq_handler+0x92a/0x12f0 [iwlwifi]
+ irq_thread_fn+0x20/0x50
+ irq_thread+0x11f/0x150
+ kthread+0xd2/0xf0
+ ret_from_fork+0x42/0x70
+ } hitcount: 934 len: 5512212
+
+ Totals:
+ Hits: 1232
+ Entries: 4
+ Dropped: 0
+
+ The above shows all the netif_receive_skb callpaths and their total
+ lengths for the duration of the wget command.
+
+ The 'clear' hist trigger param can be used to clear the hash table.
+ Suppose we wanted to try another run of the previous example but
+ this time also wanted to see the complete list of events that went
+ into the histogram. In order to avoid having to set everything up
+ again, we can just clear the histogram first:
+
+ # echo 'hist:key=stacktrace:vals=len:clear' > \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+
+ Just to verify that it is in fact cleared, here's what we now see in
+ the hist file:
+
+ # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist
+ # trigger info: hist:keys=stacktrace:vals=len:sort=hitcount:size=2048 [paused]
+
+ Totals:
+ Hits: 0
+ Entries: 0
+ Dropped: 0
+
+ Since we want to see the detailed list of every netif_receive_skb
+ event occurring during the new run, which are in fact same events
+ being aggregated into the hash table, we add some additional
+ 'enable_event' events the triggering sched_process_exec and
+ sched_process_exit events as such:
+
+ # echo 'enable_event:net:netif_receive_skb if filename==/usr/bin/wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
+
+ # echo 'disable_event:net:netif_receive_skb if comm==wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
+
+ If you read the trigger files for the sched_process_exec and
+ sched_process_exit triggers, you should see two triggers for each:
+ one enabling/disabling the hist aggregation and the other
+ enabling/disabling the logging of events:
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
+ enable_event:net:netif_receive_skb:unlimited if filename==/usr/bin/wget
+ enable_hist:net:netif_receive_skb:unlimited if filename==/usr/bin/wget
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
+ enable_event:net:netif_receive_skb:unlimited if comm==wget
+ disable_hist:net:netif_receive_skb:unlimited if comm==wget
+
+ In other words, whenever either of the sched_process_exec or
+ sched_process_exit events is hit and matches 'wget', it enables or
+ disables both the histogram and the event log, and what you end up
+ with is a hash table and set of events just covering the specified
+ duration. Run the wget command again:
+
+ $ wget https://www.kernel.org/pub/linux/kernel/v3.x/patch-3.19.xz
+
+ Displaying the 'hist' file should show something similar to what you
+ saw in the last run, but this time you should also see the
+ individual events in the trace file:
+
+ # cat /sys/kernel/debug/tracing/trace
+
+ # tracer: nop
+ #
+ # entries-in-buffer/entries-written: 183/1426 #P:4
+ #
+ # _-----=> irqs-off
+ # / _----=> need-resched
+ # | / _---=> hardirq/softirq
+ # || / _--=> preempt-depth
+ # ||| / delay
+ # TASK-PID CPU# |||| TIMESTAMP FUNCTION
+ # | | | |||| | |
+ wget-15108 [000] ..s1 31769.606929: netif_receive_skb: dev=lo skbaddr=ffff88009c353100 len=60
+ wget-15108 [000] ..s1 31769.606999: netif_receive_skb: dev=lo skbaddr=ffff88009c353200 len=60
+ dnsmasq-1382 [000] ..s1 31769.677652: netif_receive_skb: dev=lo skbaddr=ffff88009c352b00 len=130
+ dnsmasq-1382 [000] ..s1 31769.685917: netif_receive_skb: dev=lo skbaddr=ffff88009c352200 len=138
+ ##### CPU 2 buffer started ####
+ irq/29-iwlwifi-559 [002] ..s. 31772.031529: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d433d00 len=2948
+ irq/29-iwlwifi-559 [002] ..s. 31772.031572: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d432200 len=1500
+ irq/29-iwlwifi-559 [002] ..s. 31772.032196: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d433100 len=2948
+ irq/29-iwlwifi-559 [002] ..s. 31772.032761: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d433000 len=2948
+ irq/29-iwlwifi-559 [002] ..s. 31772.033220: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d432e00 len=1500
+ .
+ .
+ .
--
1.9.3
Add a new tracer named function_hist:
# cat /sys/kernel/debug/tracing/available_tracers
blk mmiotrace function_hist function_graph wakeup_dl wakeup_rt wakeup
irqsoff function nop
# echo function_hist > /sys/kernel/debug/tracing/current_tracer
# cat /sys/kernel/debug/tracing/function_hist
This is essentially the same as the kernel function tracer, but
instead of logging every function call into the trace buffer, it
continually updates a tracing map which keeps a running count for each
function.
As such, it provides an exhaustive enumeration of every traceable
function called in the kernel since the tracer was enabled, along with
the number of times it was called.
Example output from an overnight run:
# cat /sys/kernel/debug/tracing/function_hist
ip: [ffffffff812002d0] inotify_release hitcount: 1
ip: [ffffffff81078c40] param_attr_show hitcount: 1
ip: [ffffffff816e2f20] inet6_csk_bind_conflict hitcount: 1
ip: [ffffffffa04bdf50] intel_modeset_preclose hitcount: 1
ip: [ffffffff812001f0] inotify_free_group_priv hitcount: 1
ip: [ffffffffa04641d0] i915_gem_context_create_ioctl hitcount: 1
ip: [ffffffffa026b100] drm_modeset_lock_all_crtcs hitcount: 1
ip: [ffffffff811fe410] fsnotify_destroy_group hitcount: 1
ip: [ffffffff810785e0] module_attr_show hitcount: 1
.
.
.
ip: [ffffffff8109a3e0] add_wait_queue hitcount: 235927661
ip: [ffffffff81716930] _raw_spin_lock hitcount: 345398436
ip: [ffffffff81713150] _cond_resched hitcount: 378571372
ip: [ffffffff816abe90] unix_poll hitcount: 413026161
ip: [ffffffff815f4510] sock_poll hitcount: 438658385
ip: [ffffffff811dc040] __fdget hitcount: 640844197
ip: [ffffffff811dba90] __fget hitcount: 657582124
ip: [ffffffff811dbfd0] __fget_light hitcount: 662386005
ip: [ffffffff817164f0] _raw_spin_unlock_irqrestore hitcount: 848890816
ip: [ffffffff817168e0] _raw_spin_lock_irqsave hitcount: 849815447
ip: [ffffffff811c09c0] fput hitcount: 892233261
Totals:
Hits: 17981015194
Entries: 5527
Dropped: 0
Signed-off-by: Tom Zanussi <[email protected]>
---
kernel/trace/Makefile | 1 +
kernel/trace/trace.c | 3 +
kernel/trace/trace.h | 11 ++
kernel/trace/trace_functions_hist.c | 345 ++++++++++++++++++++++++++++++++++++
4 files changed, 360 insertions(+)
create mode 100644 kernel/trace/trace_functions_hist.c
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 7faace3..eb2bb50 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_TRACING) += trace_printk.o
obj-$(CONFIG_TRACING) += tracing_map.o
obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
+obj-$(CONFIG_FUNCTION_TRACER) += trace_functions_hist.o
obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6c1a38a..5f9b4de 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6740,6 +6740,9 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
if (ftrace_create_function_files(tr, d_tracer))
WARN(1, "Could not allocate function filter files");
+ if (ftrace_create_function_hist_files(tr, d_tracer))
+ WARN(1, "Could not allocate function_hist filter files");
+
#ifdef CONFIG_TRACER_SNAPSHOT
trace_create_file("snapshot", 0644, d_tracer,
tr, &snapshot_fops);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 5e2e3b0..502f88b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -820,7 +820,10 @@ static inline int ftrace_trace_task(struct task_struct *task)
extern int ftrace_is_dead(void);
int ftrace_create_function_files(struct trace_array *tr,
struct dentry *parent);
+int ftrace_create_function_hist_files(struct trace_array *tr,
+ struct dentry *parent);
void ftrace_destroy_function_files(struct trace_array *tr);
+void ftrace_destroy_function_hist_files(struct trace_array *tr);
void ftrace_init_global_array_ops(struct trace_array *tr);
void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);
void ftrace_reset_array_ops(struct trace_array *tr);
@@ -837,7 +840,15 @@ ftrace_create_function_files(struct trace_array *tr,
{
return 0;
}
+static inline int
+ftrace_create_function_hist_files(struct trace_array *tr,
+ struct dentry *parent)
+{
+ return 0;
+}
static inline void ftrace_destroy_function_files(struct trace_array *tr) { }
+static inline void
+ftrace_destroy_function_hist_files(struct trace_array *tr) { }
static inline __init void
ftrace_init_global_array_ops(struct trace_array *tr) { }
static inline void ftrace_reset_array_ops(struct trace_array *tr) { }
diff --git a/kernel/trace/trace_functions_hist.c b/kernel/trace/trace_functions_hist.c
new file mode 100644
index 0000000..136ca76
--- /dev/null
+++ b/kernel/trace/trace_functions_hist.c
@@ -0,0 +1,345 @@
+/*
+ * histogram-based function tracer
+ *
+ * Copyright (C) 2015 Tom Zanussi <[email protected]>
+ *
+ * Based on code from the function_tracer, that is:
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <[email protected]>
+ * Copyright (C) 2008 Ingo Molnar <[email protected]>
+ */
+#include <linux/kallsyms.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/slab.h>
+
+#include "tracing_map.h"
+#include "trace.h"
+
+static void tracing_start_function_hist(struct trace_array *tr);
+static void tracing_stop_function_hist(struct trace_array *tr);
+static void
+function_hist_call(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct pt_regs *pt_regs);
+
+enum hist_key_flags {
+ HIST_FIELD_SYM = 1,
+ HIST_FIELD_HEX = 2,
+};
+
+struct function_hist_data {
+ atomic64_t total_hits;
+ atomic64_t drops;
+ unsigned long key_flags;
+ struct tracing_map_sort_key sort_key;
+ struct tracing_map *map;
+};
+
+#define FUNCTION_HIST_BITS_DEFAULT 16
+#define HITCOUNT_IDX 0
+
+static struct function_hist_data *function_hist_data;
+
+static int allocate_ftrace_ops(struct trace_array *tr)
+{
+ struct ftrace_ops *ops;
+
+ ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+ if (!ops)
+ return -ENOMEM;
+
+ ops->func = function_hist_call;
+ ops->flags = FTRACE_OPS_FL_RECURSION_SAFE;
+
+ tr->ops = ops;
+ ops->private = tr;
+
+ return 0;
+}
+
+static int function_hist_init(struct trace_array *tr)
+{
+ ftrace_func_t func;
+
+ /*
+ * Instance trace_arrays get their ops allocated
+ * at instance creation. Unless it failed
+ * the allocation.
+ */
+ if (!tr->ops)
+ return -ENOMEM;
+
+ func = function_hist_call;
+
+ ftrace_init_array_ops(tr, func);
+
+ tracing_start_function_hist(tr);
+
+ return 0;
+}
+
+static void function_hist_reset(struct trace_array *tr)
+{
+ tracing_stop_function_hist(tr);
+ ftrace_reset_array_ops(tr);
+}
+
+static void
+function_hist_call(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct pt_regs *pt_regs)
+{
+ struct trace_array *tr = op->private;
+ struct tracing_map_elt *elt;
+ void *key;
+ int bit;
+
+ if (unlikely(!tr->function_enabled))
+ return;
+
+ preempt_disable_notrace();
+
+ bit = trace_test_and_set_recursion(TRACE_FTRACE_START,
+ TRACE_FTRACE_MAX);
+ if (bit < 0)
+ goto out;
+
+ if (atomic64_read(&function_hist_data->drops)) {
+ atomic64_inc(&function_hist_data->drops);
+ goto out_clear;
+ }
+
+ key = (void *)&ip;
+ elt = tracing_map_insert(function_hist_data->map, key);
+ if (elt)
+ tracing_map_update_sum(elt, HITCOUNT_IDX, 1);
+ else
+ atomic64_inc(&function_hist_data->drops);
+
+ atomic64_inc(&function_hist_data->total_hits);
+ out_clear:
+ trace_clear_recursion(bit);
+ out:
+ preempt_enable_notrace();
+}
+
+static void destroy_hist_data(struct function_hist_data *hist_data)
+{
+ tracing_map_destroy(hist_data->map);
+ kfree(hist_data);
+}
+
+static inline void create_sort_key(struct function_hist_data *hist_data)
+{
+ hist_data->sort_key.field_idx = HITCOUNT_IDX;
+ hist_data->sort_key.descending = false;
+}
+
+static int create_tracing_map_fields(struct function_hist_data *hist_data)
+{
+ struct tracing_map *map = hist_data->map;
+ unsigned int idx;
+
+ idx = tracing_map_add_sum_field(map);
+ if (idx < 0)
+ return idx;
+
+ idx = tracing_map_add_key_field(map, 0, tracing_map_cmp_none);
+ if (idx < 0)
+ return idx;
+
+ return 0;
+}
+
+static struct function_hist_data *create_hist_data(unsigned int map_bits)
+{
+ struct function_hist_data *hist_data;
+ unsigned int key_size;
+ int ret = 0;
+
+ hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
+ if (!hist_data)
+ return NULL;
+
+ create_sort_key(hist_data);
+
+ key_size = sizeof(unsigned long); /* ip */
+ hist_data->map = tracing_map_create(map_bits, key_size,
+ NULL, hist_data);
+ if (IS_ERR(hist_data->map)) {
+ ret = PTR_ERR(hist_data->map);
+ hist_data->map = NULL;
+ goto free;
+ }
+
+ ret = create_tracing_map_fields(hist_data);
+ if (ret)
+ goto free;
+
+ ret = tracing_map_init(hist_data->map);
+ if (ret)
+ goto free;
+ out:
+ return hist_data;
+ free:
+ destroy_hist_data(hist_data);
+ if (ret)
+ hist_data = ERR_PTR(ret);
+ else
+ hist_data = NULL;
+
+ goto out;
+}
+
+static void tracing_start_function_hist(struct trace_array *tr)
+{
+ unsigned int hist_trigger_bits = FUNCTION_HIST_BITS_DEFAULT;
+ struct function_hist_data *hist_data;
+
+ if (function_hist_data) {
+ destroy_hist_data(function_hist_data);
+ function_hist_data = NULL;
+ }
+
+ hist_data = create_hist_data(hist_trigger_bits);
+ if (IS_ERR(hist_data))
+ return;
+
+ hist_data->key_flags |= HIST_FIELD_SYM;
+
+ function_hist_data = hist_data;
+
+ tr->function_enabled = 0;
+ register_ftrace_function(tr->ops);
+ tr->function_enabled = 1;
+}
+
+static void tracing_stop_function_hist(struct trace_array *tr)
+{
+ tr->function_enabled = 0;
+ unregister_ftrace_function(tr->ops);
+}
+
+static void function_hist_entry_print(struct seq_file *m,
+ struct function_hist_data *hist_data,
+ void *key, struct tracing_map_elt *elt)
+{
+ char str[KSYM_SYMBOL_LEN];
+ u64 uval;
+
+ if (hist_data->key_flags & HIST_FIELD_SYM) {
+ uval = *(u64 *)key;
+ kallsyms_lookup(uval, NULL, NULL, NULL, str);
+ seq_printf(m, "ip: [%llx] %-35s", uval, str);
+ } else if (hist_data->key_flags & HIST_FIELD_HEX) {
+ uval = *(u64 *)key;
+ seq_printf(m, "ip: %llx", uval);
+ } else {
+ uval = *(u64 *)key;
+ seq_printf(m, "ip: %10llu", uval);
+ }
+
+ seq_printf(m, " hitcount: %10llu",
+ tracing_map_read_sum(elt, HITCOUNT_IDX));
+
+ seq_puts(m, "\n");
+}
+
+static int print_entries(struct seq_file *m,
+ struct function_hist_data *hist_data)
+{
+ struct tracing_map_sort_entry **sort_entries = NULL;
+ struct tracing_map *map = hist_data->map;
+ unsigned int i, n_entries;
+
+ n_entries = tracing_map_sort_entries(map, &hist_data->sort_key, 1,
+ &sort_entries);
+ if (n_entries < 0)
+ return n_entries;
+
+ for (i = 0; i < n_entries; i++)
+ function_hist_entry_print(m, hist_data,
+ sort_entries[i]->key,
+ sort_entries[i]->elt);
+
+ tracing_map_destroy_sort_entries(sort_entries, n_entries);
+
+ return n_entries;
+}
+
+static int hist_show(struct seq_file *m, void *v)
+{
+ int n_entries, ret = 0;
+
+ mutex_lock(&trace_types_lock);
+
+ if (!function_hist_data)
+ goto out_unlock;
+
+ n_entries = print_entries(m, function_hist_data);
+ if (n_entries < 0) {
+ ret = n_entries;
+ n_entries = 0;
+ }
+
+ seq_printf(m, "\nTotals:\n Hits: %lu\n Entries: %u\n Dropped: %lu\n",
+ atomic64_read(&function_hist_data->total_hits),
+ n_entries, atomic64_read(&function_hist_data->drops));
+ out_unlock:
+ mutex_unlock(&trace_types_lock);
+
+ return ret;
+}
+
+static int function_hist_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, hist_show, file);
+}
+
+const struct file_operations function_hist_fops = {
+ .open = function_hist_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+int ftrace_create_function_hist_files(struct trace_array *tr,
+ struct dentry *parent)
+{
+ struct dentry *d_tracer;
+ int ret;
+
+ d_tracer = tracing_init_dentry();
+ if (IS_ERR(d_tracer))
+ return 0;
+
+ trace_create_file("function_hist", 0444, d_tracer,
+ NULL, &function_hist_fops);
+
+ ret = allocate_ftrace_ops(tr);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+void ftrace_destroy_function_hist_files(struct trace_array *tr)
+{
+ kfree(tr->ops);
+ tr->ops = NULL;
+}
+
+static struct tracer function_hist __tracer_data = {
+ .name = "function_hist",
+ .init = function_hist_init,
+ .reset = function_hist_reset,
+ .allow_instances = true,
+#ifdef CONFIG_FTRACE_SELFTEST
+ .selftest = trace_selftest_startup_function,
+#endif
+};
+
+static __init int init_function_hist(void)
+{
+ return register_tracer(&function_hist);
+}
+fs_initcall(init_function_hist);
--
1.9.3
On 2015/06/09 6:31, Tom Zanussi wrote:
> This is v7 of the 'hist triggers' patchset, following feedback from
> v6.
>
> Changes from v6:
>
> This version adds a new 'sym-offset' modifier as requested by Masami.
> I implemented it as a modifier rather than using the trace option as
> suggested, in part because I wanted to keep it all self-contained and
> it seemed more consistent to just add it alongside the 'sym' modifier.
> Also, hist triggers arent't really a tracer and therefore don't
> directly tie into the option update/callback mechanism so making use
> of it isn't as simple as a normal tracer.
>
> I also changed the sort key specification to be stricter and signal an
> error if the specified sort key wasn't found (rather than defaulting
> to hitcount in those cases), also suggested by Masami. Thanks,
> Masami, for your input!
OK, here I've ran a quick test.
-----
[root@localhost tracing]# perf probe __kmalloc caller=\$stack0 size
Added new event:
probe:__kmalloc (on __kmalloc with caller=$stack0 size)
You can now use it in all perf tools, such as:
perf record -e probe:__kmalloc -aR sleep 1
[root@localhost tracing]# echo hist:keys=caller.sym-offset,size:value=hitcount:sort=size > events/probe/__kmalloc/trigger
[root@localhost tracing]# echo 1 > events/probe/__kmalloc/enable
[root@localhost tracing]# cat events/probe/__kmalloc/hist
# trigger info: hist:keys=caller.sym-offset,size:vals=hitcount:sort=size:size=2048 [active]
{ caller: [ffffffff811e1142] shmem_initxattrs+0x92/0xe0 , size: 17 } hitcount: 14
{ caller: [ffffffff81296860] load_elf_binary+0x240/0x10e0 , size: 28 } hitcount: 4
{ caller: [ffffffff813ed384] security_context_to_sid_core+0x64/0x280 , size: 30 } hitcount: 84
{ caller: [ffffffff813ec0cc] context_struct_to_string+0x11c/0x220 , size: 36 } hitcount: 14
{ caller: [ffffffff8125bf84] alloc_fdmem+0x24/0x40 , size: 64 } hitcount: 17
{ caller: [ffffffff812653cc] simple_xattr_alloc+0x2c/0x70 , size: 68 } hitcount: 14
{ caller: [ffffffffa0304770] __nf_ct_ext_add_length+0x160/0x1a0 [nf_conntrack] , size: 96 } hitcount: 6
{ caller: [ffffffff81395ca7] kmem_alloc+0x77/0xf0 , size: 112 } hitcount: 2
{ caller: [ffffffff81416058] bio_alloc_bioset+0x248/0x330 , size: 152 } hitcount: 12
{ caller: [ffffffff81395ca7] kmem_alloc+0x77/0xf0 , size: 384 } hitcount: 2
{ caller: [ffffffff812965f6] load_elf_phdrs+0x76/0xa0 , size: 392 } hitcount: 4
{ caller: [ffffffff812965f6] load_elf_phdrs+0x76/0xa0 , size: 504 } hitcount: 4
{ caller: [ffffffff8169cbdb] sk_prot_alloc+0xcb/0x1b0 , size: 1136 } hitcount: 2
{ caller: [ffffffff8125bf84] alloc_fdmem+0x24/0x40 , size: 2048 } hitcount: 17
{ caller: [ffffffff812628fb] seq_buf_alloc+0x1b/0x50 , size: 3024 } hitcount: 2
{ caller: [ffffffff812628fb] seq_buf_alloc+0x1b/0x50 , size: 4096 } hitcount: 35
{ caller: [ffffffff81196540] tracing_map_sort_entries+0x30/0x5c0 , size: 16384 } hitcount: 1
Totals:
Hits: 234
Entries: 17
Dropped: 0
-----
Looks good to me :)
-----
[root@localhost tracing]# echo hist:keys=caller.sym-offset,size:value=hitcount:sort=XXX > events/probe/__kmalloc/trigger
-bash: echo: write error: Invalid argument
[root@localhost tracing]# echo hist:keys=caller.sym-offset,size:value=abc > events/probe/__kmalloc/trigger
-bash: echo: write error: Invalid argument
[root@localhost tracing]# echo hist:keys=yyy > events/probe/__kmalloc/trigger
-bash: echo: write error: Invalid argument
-----
Also, it seems to check parse error correctly.
I'll take a look for each patch.
Thank you,
>
> Also updated the Documentation and tracing/README to reflect the
> changes.
>
> Changes from v5:
>
> This version adds support for compound keys, along with the related
> ability to sort using primary and secondary keys. This was mentioned
> in previous versions as the last important piece that remained
> unimplemented, and is now implemented. (I didn't have time to get to
> the couple of enhancements suggested by Masami, but I expect to be
> able to add those later on top of these.)
>
> Because we now support compound keys and it's not immediately clear in
> the output exactly which fields correspond to keys, the key(s),
> compound or not, are now enclosed by curly braces.
>
> The Documentation and README have been updated to reflect the changes,
> and several new examples have been added to illustrate how to use
> compound keys.
>
> Also, the code was updated to work with the new ftrace_event_file,
> etc, renaming in tracing/for-next.
>
> Changes from v4:
>
> This version addresses some problems and suggestions made by Daniel
> Wagner - a lot of the code was reworked to get rid of the distinction
> between keys and values, and as a result, both keys and values can be
> used as sort keys. As suggested, it also allows 'val=' to be absent
> in a trigger command - if no 'val' is specified, hitcount is assumed
> and automatically used as the only val.
>
> The map code was also separated out into a separate file,
> tracing_map.c, allowing it to be reused. It also adds a second tracer
> called function_hist that actually does reuse the code, as an RFC
> patch.
>
> Patch 01/10 [tracing: Update cond flag when enabling or disabling..]
> is a fix for a problem noticed by Daniel and that fixes a problem in
> existing trigger code and should be applied regardless of whether the
> rest of the patchset is merged.
>
> As mentioned, patch 10/10 is an RFC patch implementing a new tracer
> based on the function tracer code. It's a fun little tool and is
> useful for a specific problem I'm working on (and is also a nice test
> of the tracing_map code), but is an RFC because first, I'm not sure it
> would really be of general interest and secondly, it's POC-level
> quality and I'd need to spend more time fixing it up to make it
> upstreamable, but I don't want to waste my time if not.
>
> There are a couple of important bits of functionality that were
> present in v1 but not yet reimplemented in v5.
>
> The first is support for compound keys. Currently, maps can only be
> keyed on a single event field, whereas in v1 they could be keyed on
> multiple keys. With support for compound keys, you can create much
> more interesting output, such as for example per-pid lists of
> syscalls or read counts e.g.:
>
> # echo 'hist:keys=common_pid.execname,id.syscall:vals=hitcount' > \
> /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
>
> # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist
>
> key: common_pid:bash[3112], id:sys_write vals: count:69
> key: common_pid:bash[3112], id:sys_rt_sigprocmask vals: count:218
>
> key: common_pid:update-notifier[3164], id:sys_poll vals: count:37
> key: common_pid:update-notifier[3164], id:sys_recvfrom vals: count:118
>
> key: common_pid:deja-dup-monito[3194], id:sys_sendto vals: count:1
> key: common_pid:deja-dup-monito[3194], id:sys_read vals: count:4
> key: common_pid:deja-dup-monito[3194], id:sys_poll vals: count:8
> key: common_pid:deja-dup-monito[3194], id:sys_recvmsg vals: count:8
> key: common_pid:deja-dup-monito[3194], id:sys_getegid vals: count:8
>
> key: common_pid:emacs[3275], id:sys_fsync vals: count:1
> key: common_pid:emacs[3275], id:sys_open vals: count:1
> key: common_pid:emacs[3275], id:sys_symlink vals: count:2
> key: common_pid:emacs[3275], id:sys_poll vals: count:23
> key: common_pid:emacs[3275], id:sys_select vals: count:23
> key: common_pid:emacs[3275], id:unknown_syscall vals: count:34
> key: common_pid:emacs[3275], id:sys_ioctl vals: count:60
> key: common_pid:emacs[3275], id:sys_rt_sigprocmask vals: count:116
>
> key: common_pid:cat[3323], id:sys_munmap vals: count:1
> key: common_pid:cat[3323], id:sys_fadvise64 vals: count:1
>
> Related to that is support for sorting on multiple fields. Currently,
> you can sort using only a primary key. Being able to sort on multiple
> or at least a secondary key is indispensible for seeing trends when
> displaying multiple values.
>
> Changes from v3:
>
> v4 fixes the race in tracing_map_insert() noted in v3, where
> map.val.key could be checked even if map.val wasn't yet set. The
> simple fix for that in tracing_map_insert() introduces the possibility
> of duplicates in the map, which though rare, need to be accounted for
> in the output. To address that, duplicate-merging code was added to
> the map-printing code.
>
> It was also pointed out that it didn't seem correct to include
> module.h, but the fix for that has deeper roots and is being addressed
> by a separate patchset; for now we need to continue including
> module.h, though prompted by that I did some other header include
> cleanup.
>
> The functionality remains the same as v2, but this version no longer
> tries to export and use bpf_maps, and more importantly removes the
> associated GFP_NOTRACE/trace event hacks and kmem macros required to
> work around the bpf_map implementation.
>
> The tracing_map functionality is instead built on top of a simple
> lock-free map algorithm originated by Dr. Cliff Click (see references
> in the code for more details), which though too restrictive to be
> general-purpose in its current form, functions nicely as a
> special-purpose tracing map.
>
> v3 also moves the hist triggers code into a separate file and puts it
> all behind a new config option, CONFIG_HIST_TRIGGERS. It also merges
> in the sorting code rather than keeping it as a separate patch.
>
> This patchset also includes a couple other new and related triggers,
> enable_hist and disable_hist, very similar to the existing
> enable_event/disable_event triggers used to automatically enable and
> disable events based on a triggering condition, but in this case
> allowing hist triggers to be enabled and disabled in the same way.
>
> - Added an insert check for val before checking the key associated with val
> - Added code to merge possible duplicates in the map
>
> Changes from v2:
> - reimplemented tracing_map, replacing bpf_map with nmi-safe/lock-free map
> - removed GPF_NOTRACE, kmalloc/free macros and event hacks needed by bpf_maps
> - moved hist triggers from trace_events_trigger.c to trace_events_hist.c
> - added CONFIG_HIST_TRIGGERS config option
> - consolidated sorting code with main patch
>
> Changes from v1:
> - completely rewritten on top of tracing_map (renamed and exported bpf_map)
> - added map clearing and client ops to tracing_map
> - changed the name from 'hash' triggers to 'hist' triggers
> - added new trigger 'pause' feature
> - added new enable_hist and disable_hist triggers
> - added usage for hist/enable_hist/disable hist to tracing/README
> - moved examples into Documentation/trace/event.txt
> - added ___GFP_NOTRACE, kmalloc/kfree macros, and conditional kmem tracepoints
>
> The following changes since commit a497adb45b8691f7e477e711a1a4bd54748d64fe:
>
> ring-buffer: Add enum names for the context levels (2015-05-29 10:39:08 -0400)
>
> are available in the git repository at:
>
> git://git.yoctoproject.org/linux-yocto-contrib.git tzanussi/hist-triggers-v7
> http://git.yoctoproject.org/cgit/cgit.cgi/linux-yocto-contrib/log/?h=tzanussi/hist-triggers-v7
>
> Tom Zanussi (10):
> tracing: Update cond flag when enabling or disabling a trigger
> tracing: Make ftrace_event_field checking functions available
> tracing: Add event record param to trigger_ops.func()
> tracing: Add get_syscall_name()
> tracing: Add a per-event-trigger 'paused' field
> trace: Add lock-free tracing_map
> tracing: Add 'hist' event trigger command
> tracing: Add enable_hist/disable_hist triggers
> tracing: Add 'hist' trigger Documentation
> ftrace: Add function_hist tracer
>
> Documentation/trace/events.txt | 1131 ++++++++++++++++++++++++++++
> include/linux/trace_events.h | 9 +-
> kernel/trace/Kconfig | 14 +
> kernel/trace/Makefile | 3 +
> kernel/trace/trace.c | 69 ++
> kernel/trace/trace.h | 88 ++-
> kernel/trace/trace_events.c | 4 +
> kernel/trace/trace_events_filter.c | 12 -
> kernel/trace/trace_events_hist.c | 1407 +++++++++++++++++++++++++++++++++++
> kernel/trace/trace_events_trigger.c | 149 ++--
> kernel/trace/trace_functions_hist.c | 345 +++++++++
> kernel/trace/trace_syscalls.c | 11 +
> kernel/trace/tracing_map.c | 920 +++++++++++++++++++++++
> kernel/trace/tracing_map.h | 143 ++++
> 14 files changed, 4221 insertions(+), 84 deletions(-)
> create mode 100644 kernel/trace/trace_events_hist.c
> create mode 100644 kernel/trace/trace_functions_hist.c
> create mode 100644 kernel/trace/tracing_map.c
> create mode 100644 kernel/trace/tracing_map.h
>
--
Masami HIRAMATSU
Linux Technology Research Center, System Productivity Research Dept.
Center for Technology Innovation - Systems Engineering
Hitachi, Ltd., Research & Development Group
E-mail: [email protected]
On 2015/06/09 6:32, Tom Zanussi wrote:
> 'hist' triggers allow users to continually aggregate trace events,
> which can then be viewed afterwards by simply reading a 'hist' file
> containing the aggregation in a human-readable format.
>
> The basic idea is very simple and boils down to a mechanism whereby
> trace events, rather than being exhaustively dumped in raw form and
> viewed directly, are automatically 'compressed' into meaningful tables
> completely defined by the user.
>
> This is done strictly via single-line command-line commands and
> without the aid of any kind of programming language or interpreter.
>
> A surprising number of typical use cases can be accomplished by users
> via this simple mechanism. In fact, a large number of the tasks that
> users typically do using the more complicated script-based tracing
> tools, at least during the initial stages of an investigation, can be
> accomplished by simply specifying a set of keys and values to be used
> in the creation of a hash table.
>
> The Linux kernel trace event subsystem happens to provide an extensive
> list of keys and values ready-made for such a purpose in the form of
> the event format files associated with each trace event. By simply
> consulting the format file for field names of interest and by plugging
> them into the hist trigger command, users can create an endless number
> of useful aggregations to help with investigating various properties
> of the system. See Documentation/trace/events.txt for examples.
>
> hist triggers are implemented on top of the existing event trigger
> infrastructure, and as such are consistent with the existing triggers
> from a user's perspective as well.
>
> The basic syntax follows the existing trigger syntax. Users start an
> aggregation by writing a 'hist' trigger to the event of interest's
> trigger file:
>
> # echo hist:keys=xxx:values=yyy [ if filter] > event/trigger
>
> Once a hist trigger has been set up, by default it continually
> aggregates every matching event into a hash table using the event key
> and value fields specified.
>
> To view the aggregation at any point in time, simply read the 'hist'
> file in the same directory as the 'trigger' file:
>
> # cat event/hist
>
> The detailed syntax provides additional options for user control, and
> is described exhaustively in Documentation/trace/events.txt and in the
> virtual tracing/README file in the tracing subsystem.
>
> Signed-off-by: Tom Zanussi <[email protected]>
>
> fixes sort key parsing
>
> Signed-off-by: Tom Zanussi <[email protected]>
>
> Add sym-offset
>
> And change sym, add more space for both. And make modifiers stricter.
>
> Signed-off-by: Tom Zanussi <[email protected]>
Why does this have same singned-off-bys? :)
BTW, this looks a bit big to review and including many different features.
It seems to be broken into several incremental patches, like
- Add a basic hist trigger (key, val, size and simple hitcount sorting)
- Add multiple keys and values support
- Add "sort" attribute
- Add "continue" and "pause" attribute
- Add "clear" attribute
- Support ".hex" option for keys and vals
- Support ".sym" and ".sym-offset" options for keys and vals
- Support ".execname" option for keys
- Support ".syscall" option for keys
- Support ".stacktrace" option for keys
Thank you,
--
Masami HIRAMATSU
Linux Technology Research Center, System Productivity Research Dept.
Center for Technology Innovation - Systems Engineering
Hitachi, Ltd., Research & Development Group
E-mail: [email protected]
On Wed, 2015-06-10 at 23:14 +0900, Masami Hiramatsu wrote:
> On 2015/06/09 6:32, Tom Zanussi wrote:
> > 'hist' triggers allow users to continually aggregate trace events,
> > which can then be viewed afterwards by simply reading a 'hist' file
> > containing the aggregation in a human-readable format.
> >
> > The basic idea is very simple and boils down to a mechanism whereby
> > trace events, rather than being exhaustively dumped in raw form and
> > viewed directly, are automatically 'compressed' into meaningful tables
> > completely defined by the user.
> >
> > This is done strictly via single-line command-line commands and
> > without the aid of any kind of programming language or interpreter.
> >
> > A surprising number of typical use cases can be accomplished by users
> > via this simple mechanism. In fact, a large number of the tasks that
> > users typically do using the more complicated script-based tracing
> > tools, at least during the initial stages of an investigation, can be
> > accomplished by simply specifying a set of keys and values to be used
> > in the creation of a hash table.
> >
> > The Linux kernel trace event subsystem happens to provide an extensive
> > list of keys and values ready-made for such a purpose in the form of
> > the event format files associated with each trace event. By simply
> > consulting the format file for field names of interest and by plugging
> > them into the hist trigger command, users can create an endless number
> > of useful aggregations to help with investigating various properties
> > of the system. See Documentation/trace/events.txt for examples.
> >
> > hist triggers are implemented on top of the existing event trigger
> > infrastructure, and as such are consistent with the existing triggers
> > from a user's perspective as well.
> >
> > The basic syntax follows the existing trigger syntax. Users start an
> > aggregation by writing a 'hist' trigger to the event of interest's
> > trigger file:
> >
> > # echo hist:keys=xxx:values=yyy [ if filter] > event/trigger
> >
> > Once a hist trigger has been set up, by default it continually
> > aggregates every matching event into a hash table using the event key
> > and value fields specified.
> >
> > To view the aggregation at any point in time, simply read the 'hist'
> > file in the same directory as the 'trigger' file:
> >
> > # cat event/hist
> >
> > The detailed syntax provides additional options for user control, and
> > is described exhaustively in Documentation/trace/events.txt and in the
> > virtual tracing/README file in the tracing subsystem.
> >
> > Signed-off-by: Tom Zanussi <[email protected]>
> >
> > fixes sort key parsing
> >
> > Signed-off-by: Tom Zanussi <[email protected]>
> >
> > Add sym-offset
> >
> > And change sym, add more space for both. And make modifiers stricter.
> >
> > Signed-off-by: Tom Zanussi <[email protected]>
>
>
> Why does this have same singned-off-bys? :)
>
Hmm, yeah, forgot to squash the comments when I squashed the commits,
thanks for noticing.
> BTW, this looks a bit big to review and including many different features.
> It seems to be broken into several incremental patches, like
>
> - Add a basic hist trigger (key, val, size and simple hitcount sorting)
> - Add multiple keys and values support
> - Add "sort" attribute
> - Add "continue" and "pause" attribute
> - Add "clear" attribute
> - Support ".hex" option for keys and vals
> - Support ".sym" and ".sym-offset" options for keys and vals
> - Support ".execname" option for keys
> - Support ".syscall" option for keys
> - Support ".stacktrace" option for keys
>
Yeah, it just kept growing and growing with each revision...
Now that it's pretty much feature-complete, I'll break the features out
again in a new revision, for easier review.
Thanks,
Tom
>
> Thank you,
>
>
>
Hi Tom,
I tried to play with this patchset, and it worked greatly. Thanks for
your work!
But I found that it doesn't handle string fields properly so I can see
failure on accessing 'filename' field in sched_process_exec event.
Below is my fix for that.. Can you take a look at it?
Thanks,
Namhyung
>From e0442e9aec9740e4f20931ff10545f07c8d6d346 Mon Sep 17 00:00:00 2001
From: Namhyung Kim <[email protected]>
Date: Thu, 11 Jun 2015 11:48:41 +0900
Subject: [PATCH] tracing: Support string type key properly
The string in a trace event is usually recorded as dynamic array which
is variable length. But current hist code only support fixed length
array so it cannot support most strings.
This patch fixes it by checking filter_type of the field and get
proper pointer with it. With this, it can get a histogram of exec()
based on filenames like below:
# cd /sys/kernel/tracing/events/sched/sched_process_exec
# cat 'hist:key=filename' > trigger
# ps
PID TTY TIME CMD
1 ? 00:00:00 init
29 ? 00:00:00 sh
38 ? 00:00:00 ps
# ls
enable filter format hist id trigger
# cat hist
# trigger info: hist:keys=filename:vals=hitcount:sort=hitcount:size=2048 [active]
{ filename: /usr/bin/ps } hitcount: 1
{ filename: /usr/bin/ls } hitcount: 1
{ filename: /usr/bin/cat } hitcount: 1
Totals:
Hits: 3
Entries: 3
Dropped: 0
Cc: Tom Zanussi <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
---
kernel/trace/trace_events_hist.c | 47 +++++++++++++++++++++++++++++++++++++---
1 file changed, 44 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 5ea18956497d..d5edf9fa5aea 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -52,6 +52,22 @@ static u64 hist_field_string(struct hist_field *hist_field, void *event)
return (u64)addr;
}
+static u64 hist_field_dynstring(struct hist_field *hist_field, void *event)
+{
+ u32 str_item = *(u32 *)(event + hist_field->field->offset);
+ int str_loc = str_item & 0xffff;
+ char *addr = (char *)(event + str_loc);
+
+ return (u64)addr;
+}
+
+static u64 hist_field_pstring(struct hist_field *hist_field, void *event)
+{
+ char **addr = (char **)(event + hist_field->field->offset);
+
+ return (u64)*addr;
+}
+
#define DEFINE_HIST_FIELD_FN(type) \
static u64 hist_field_##type(struct hist_field *hist_field, void *event)\
{ \
@@ -330,7 +346,13 @@ static struct hist_field *create_hist_field(struct ftrace_event_field *field,
if (is_string_field(field)) {
flags |= HIST_FIELD_STRING;
- hist_field->fn = hist_field_string;
+
+ if (field->filter_type == FILTER_STATIC_STRING)
+ hist_field->fn = hist_field_string;
+ else if (field->filter_type == FILTER_DYN_STRING)
+ hist_field->fn = hist_field_dynstring;
+ else
+ hist_field->fn = hist_field_pstring;
} else {
hist_field->fn = select_value_fn(field->size,
field->is_signed);
@@ -485,7 +507,10 @@ static int create_key_field(struct hist_trigger_data *hist_data,
goto out;
}
- key_size = field->size;
+ if (is_string_field(field)) /* should be last key field */
+ key_size = HIST_KEY_SIZE_MAX - key_offset;
+ else
+ key_size = field->size;
}
hist_data->fields[key_idx] = create_hist_field(field, flags);
@@ -791,8 +816,24 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec)
key = (void *)&field_contents;
if (hist_data->n_keys > 1) {
+ /* ensure NULL-termination */
+ size_t size = key_field->size - 1;
+
+ if (key_field->flags & HIST_FIELD_STRING) {
+ struct ftrace_event_field *field;
+
+ field = key_field->field;
+ if (field->filter_type == FILTER_DYN_STRING)
+ size = *(u32 *)(rec + field->offset) >> 16;
+ else if (field->filter_type == FILTER_PTR_STRING)
+ size = strlen(key);
+
+ if (size > key_field->size - 1)
+ size = key_field->size - 1;
+ }
+
memcpy(compound_key + key_field->offset, key,
- key_field->size);
+ size);
}
}
}
--
2.4.2
Hi Namhyung,
On Thu, 2015-06-11 at 12:05 +0900, Namhyung Kim wrote:
> Hi Tom,
>
> I tried to play with this patchset, and it worked greatly. Thanks for
> your work!
>
Great, and thanks for trying it out and especially for sending this
patch.
> But I found that it doesn't handle string fields properly so I can see
> failure on accessing 'filename' field in sched_process_exec event.
> Below is my fix for that.. Can you take a look at it?
>
It looks good to me - I was able to verify both the problem and that
this fixes it - thanks very much for taking the time to figure this out.
I'll include this with my next revision of the patchset, which basically
just splits things up into smaller patches for review. I may also make
a couple modifications in addition to this - at minimum, enforcing the
'should be the last key field' comment, but I'll try to think of a
better way, so that that comment can be removed instead...
Thanks again,
Tom
> Thanks,
> Namhyung
>
>
>
> From e0442e9aec9740e4f20931ff10545f07c8d6d346 Mon Sep 17 00:00:00 2001
> From: Namhyung Kim <[email protected]>
> Date: Thu, 11 Jun 2015 11:48:41 +0900
> Subject: [PATCH] tracing: Support string type key properly
>
> The string in a trace event is usually recorded as dynamic array which
> is variable length. But current hist code only support fixed length
> array so it cannot support most strings.
>
> This patch fixes it by checking filter_type of the field and get
> proper pointer with it. With this, it can get a histogram of exec()
> based on filenames like below:
>
> # cd /sys/kernel/tracing/events/sched/sched_process_exec
> # cat 'hist:key=filename' > trigger
> # ps
> PID TTY TIME CMD
> 1 ? 00:00:00 init
> 29 ? 00:00:00 sh
> 38 ? 00:00:00 ps
> # ls
> enable filter format hist id trigger
> # cat hist
> # trigger info: hist:keys=filename:vals=hitcount:sort=hitcount:size=2048 [active]
>
> { filename: /usr/bin/ps } hitcount: 1
> { filename: /usr/bin/ls } hitcount: 1
> { filename: /usr/bin/cat } hitcount: 1
>
> Totals:
> Hits: 3
> Entries: 3
> Dropped: 0
>
> Cc: Tom Zanussi <[email protected]>
> Cc: Masami Hiramatsu <[email protected]>
> Signed-off-by: Namhyung Kim <[email protected]>
> ---
> kernel/trace/trace_events_hist.c | 47 +++++++++++++++++++++++++++++++++++++---
> 1 file changed, 44 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 5ea18956497d..d5edf9fa5aea 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -52,6 +52,22 @@ static u64 hist_field_string(struct hist_field *hist_field, void *event)
> return (u64)addr;
> }
>
> +static u64 hist_field_dynstring(struct hist_field *hist_field, void *event)
> +{
> + u32 str_item = *(u32 *)(event + hist_field->field->offset);
> + int str_loc = str_item & 0xffff;
> + char *addr = (char *)(event + str_loc);
> +
> + return (u64)addr;
> +}
> +
> +static u64 hist_field_pstring(struct hist_field *hist_field, void *event)
> +{
> + char **addr = (char **)(event + hist_field->field->offset);
> +
> + return (u64)*addr;
> +}
> +
> #define DEFINE_HIST_FIELD_FN(type) \
> static u64 hist_field_##type(struct hist_field *hist_field, void *event)\
> { \
> @@ -330,7 +346,13 @@ static struct hist_field *create_hist_field(struct ftrace_event_field *field,
>
> if (is_string_field(field)) {
> flags |= HIST_FIELD_STRING;
> - hist_field->fn = hist_field_string;
> +
> + if (field->filter_type == FILTER_STATIC_STRING)
> + hist_field->fn = hist_field_string;
> + else if (field->filter_type == FILTER_DYN_STRING)
> + hist_field->fn = hist_field_dynstring;
> + else
> + hist_field->fn = hist_field_pstring;
> } else {
> hist_field->fn = select_value_fn(field->size,
> field->is_signed);
> @@ -485,7 +507,10 @@ static int create_key_field(struct hist_trigger_data *hist_data,
> goto out;
> }
>
> - key_size = field->size;
> + if (is_string_field(field)) /* should be last key field */
> + key_size = HIST_KEY_SIZE_MAX - key_offset;
> + else
> + key_size = field->size;
> }
>
> hist_data->fields[key_idx] = create_hist_field(field, flags);
> @@ -791,8 +816,24 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec)
> key = (void *)&field_contents;
>
> if (hist_data->n_keys > 1) {
> + /* ensure NULL-termination */
> + size_t size = key_field->size - 1;
> +
> + if (key_field->flags & HIST_FIELD_STRING) {
> + struct ftrace_event_field *field;
> +
> + field = key_field->field;
> + if (field->filter_type == FILTER_DYN_STRING)
> + size = *(u32 *)(rec + field->offset) >> 16;
> + else if (field->filter_type == FILTER_PTR_STRING)
> + size = strlen(key);
> +
> + if (size > key_field->size - 1)
> + size = key_field->size - 1;
> + }
> +
> memcpy(compound_key + key_field->offset, key,
> - key_field->size);
> + size);
> }
> }
> }
Why v3 in the subject?
On Mon, 8 Jun 2015 16:32:00 -0500
Tom Zanussi <[email protected]> wrote:
> When a trigger is enabled, the cond flag should be set beforehand,
> otherwise a trigger that's expecting to process a trace record
> (e.g. one with post_trigger set) could be invoked without one.
>
> Likewise a trigger's cond flag should be reset after it's disabled,
> not before.
>
> Signed-off-by: Tom Zanussi <[email protected]>
> Signed-off-by: Daniel Wagner <[email protected]>
Why is Daniel signed off by here?
-- Steve
> ---
> kernel/trace/trace_events_trigger.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
> index 42a4009..4d2f3cc 100644
> --- a/kernel/trace/trace_events_trigger.c
> +++ b/kernel/trace/trace_events_trigger.c
> @@ -543,11 +543,12 @@ static int register_trigger(char *glob, struct event_trigger_ops *ops,
> list_add_rcu(&data->list, &file->triggers);
> ret++;
>
> + update_cond_flag(file);
> if (trace_event_trigger_enable_disable(file, 1) < 0) {
> list_del_rcu(&data->list);
> + update_cond_flag(file);
> ret--;
> }
> - update_cond_flag(file);
> out:
> return ret;
> }
> @@ -575,8 +576,8 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
> if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
> unregistered = true;
> list_del_rcu(&data->list);
> - update_cond_flag(file);
> trace_event_trigger_enable_disable(file, 0);
> + update_cond_flag(file);
> break;
> }
> }
> @@ -1319,11 +1320,12 @@ static int event_enable_register_trigger(char *glob,
> list_add_rcu(&data->list, &file->triggers);
> ret++;
>
> + update_cond_flag(file);
> if (trace_event_trigger_enable_disable(file, 1) < 0) {
> list_del_rcu(&data->list);
> + update_cond_flag(file);
> ret--;
> }
> - update_cond_flag(file);
> out:
> return ret;
> }
> @@ -1344,8 +1346,8 @@ static void event_enable_unregister_trigger(char *glob,
> (enable_data->file == test_enable_data->file)) {
> unregistered = true;
> list_del_rcu(&data->list);
> - update_cond_flag(file);
> trace_event_trigger_enable_disable(file, 0);
> + update_cond_flag(file);
> break;
> }
> }
On Mon, 8 Jun 2015 16:32:05 -0500
Tom Zanussi <[email protected]> wrote:
> Add tracing_map, a special-purpose lock-free map for tracing.
>
> tracing_map is designed to aggregate or 'sum' one or more values
> associated with a specific object of type tracing_map_elt, which
What is "elt"? I don't see it explained anywhere.
> is associated by the map to a given key.
>
> It provides various hooks allowing per-tracer customization and is
> separated out into a separate file in order to allow it to be shared
> between multiple tracers, but isn't meant to be generally used outside
> of that context.
>
> The tracing_map implementation was inspired by lock-free map
> algorithms originated by Dr. Cliff Click:
>
> http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable
> http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf
>
> Signed-off-by: Tom Zanussi <[email protected]>
> +/**
> + * tracing_map_update_sum - Add a value to a tracing_map_elt's sum
> + * @elt: The tracing_map_elt
Not a very useful comment, as I have no idea what "elt" is.
I'll continue to review this patch about the mysterious element "elt".
-- Steve
> + * @i: The index of the given sum associated with the tracing_map_elt
> + * @n: The value to add to the sum
> + *
> + * Add n to sum i associated with the specified tracing_map_elt
> + * instance. The index i is the index returned by the call to
> + * tracing_map_add_sum_field() when the tracing map was set up.
> + */
> +void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n)
> +{
> + atomic64_add(n, &elt->fields[i].sum);
> +}
> +
On Mon, 8 Jun 2015 16:32:05 -0500
Tom Zanussi <[email protected]> wrote:
> +/**
> + * tracing_map_read_sum - Return the value of a tracing_map_elt's sum
> + * @elt: The tracing_map_elt
Eggs, lettuce, and tomato! Yummmm!
> +static int cmp_entries_dup(const struct tracing_map_sort_entry **a,
> + const struct tracing_map_sort_entry **b)
> +{
> + int ret = 0;
> +
> + if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size))
> + ret = 1;
> +
> + return ret;
> +}
> +
> +static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> + const struct tracing_map_sort_entry **b)
> +{
> + const struct tracing_map_elt *elt_a, *elt_b;
> + struct tracing_map_sort_key *sort_key;
> + struct tracing_map_field *field;
> + tracing_map_cmp_fn_t cmp_fn;
> + void *val_a, *val_b;
> + int ret = 0;
> +
> + elt_a = (*a)->elt;
> + elt_b = (*b)->elt;
> +
> + sort_key = &elt_a->map->sort_key;
> +
> + field = &elt_a->fields[sort_key->field_idx];
> + cmp_fn = field->cmp_fn;
> +
> + val_a = &elt_a->fields[sort_key->field_idx].sum;
> + val_b = &elt_b->fields[sort_key->field_idx].sum;
> +
> + ret = cmp_fn(val_a, val_b);
> + if (sort_key->descending)
> + ret = -ret;
> +
> + return ret;
> +}
> +
> +static int cmp_entries_key(const struct tracing_map_sort_entry **a,
> + const struct tracing_map_sort_entry **b)
> +{
> + const struct tracing_map_elt *elt_a, *elt_b;
> + struct tracing_map_sort_key *sort_key;
> + struct tracing_map_field *field;
> + tracing_map_cmp_fn_t cmp_fn;
> + void *val_a, *val_b;
> + int ret = 0;
> +
> + elt_a = (*a)->elt;
> + elt_b = (*b)->elt;
> +
> + sort_key = &elt_a->map->sort_key;
> +
> + field = &elt_a->fields[sort_key->field_idx];
> +
> + cmp_fn = field->cmp_fn;
> +
> + val_a = elt_a->key + field->offset;
> + val_b = elt_b->key + field->offset;
> +
> + ret = cmp_fn(val_a, val_b);
> + if (sort_key->descending)
> + ret = -ret;
> +
> + return ret;
> +}
> +
> +static void destroy_sort_entry(struct tracing_map_sort_entry *entry)
> +{
> + if (!entry)
> + return;
> +
> + if (entry->elt_copied)
> + tracing_map_elt_free(entry->elt);
> +
> + kfree(entry);
> +}
> +
> +/**
> + * tracing_map_destroy_entries - Destroy a tracing_map_sort_entries() array
> + * @entries: The entries to destroy
> + * @n_entries: The number of entries in the array
> + *
> + * Destroy the elements returned by a tracing_map_sort_entries() call.
> + */
> +void tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries,
> + unsigned int n_entries)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < n_entries; i++)
> + destroy_sort_entry(entries[i]);
> +}
> +
> +static struct tracing_map_sort_entry *
> +create_sort_entry(void *key, struct tracing_map_elt *elt)
> +{
> + struct tracing_map_sort_entry *sort_entry;
> +
> + sort_entry = kzalloc(sizeof(*sort_entry), GFP_KERNEL);
> + if (!sort_entry)
> + return NULL;
> +
> + sort_entry->key = key;
> + sort_entry->elt = elt;
> +
> + return sort_entry;
> +}
> +
> +static struct tracing_map_elt *copy_elt(struct tracing_map_elt *elt)
> +{
> + struct tracing_map_elt *dup_elt;
> + unsigned int i;
> +
> + dup_elt = tracing_map_elt_alloc(elt->map);
> + if (!dup_elt)
> + return NULL;
> +
> + if (elt->map->ops && elt->map->ops->elt_copy)
> + elt->map->ops->elt_copy(dup_elt, elt);
> +
> + dup_elt->private_data = elt->private_data;
> + memcpy(dup_elt->key, elt->key, elt->map->key_size);
> +
> + for (i = 0; i < elt->map->n_fields; i++) {
> + atomic64_set(&dup_elt->fields[i].sum,
> + atomic64_read(&elt->fields[i].sum));
> + dup_elt->fields[i].cmp_fn = elt->fields[i].cmp_fn;
> + }
> +
> + return dup_elt;
> +}
> +
> +static int merge_dup(struct tracing_map_sort_entry **sort_entries,
> + unsigned int target, unsigned int dup)
> +{
> + struct tracing_map_elt *target_elt, *elt;
> + bool first_dup = (target - dup) == 1;
> + int i;
> +
> + if (first_dup) {
> + elt = sort_entries[target]->elt;
> + target_elt = copy_elt(elt);
> + if (!target_elt)
> + return -ENOMEM;
> + sort_entries[target]->elt = target_elt;
> + sort_entries[target]->elt_copied = true;
> + } else
> + target_elt = sort_entries[target]->elt;
> +
> + elt = sort_entries[dup]->elt;
> +
> + for (i = 0; i < elt->map->n_fields; i++)
> + atomic64_add(atomic64_read(&elt->fields[i].sum),
> + &target_elt->fields[i].sum);
> +
> + sort_entries[dup]->dup = true;
> +
> + return 0;
> +}
> +
> +static int merge_dups(struct tracing_map_sort_entry **sort_entries,
> + int n_entries, unsigned int key_size)
> +{
> + unsigned int dups = 0, total_dups = 0;
> + int err, i, j;
> + void *key;
> +
> + if (n_entries < 2)
> + return total_dups;
> +
> + sort(sort_entries, n_entries, sizeof(struct tracing_map_sort_entry *),
> + (int (*)(const void *, const void *))cmp_entries_dup, NULL);
Sort.
> +
> + key = sort_entries[0]->key;
> + for (i = 1; i < n_entries; i++) {
> + if (!memcmp(sort_entries[i]->key, key, key_size)) {
> + dups++; total_dups++;
> + err = merge_dup(sort_entries, i - dups, i);
> + if (err)
> + return err;
> + continue;
> + }
> + key = sort_entries[i]->key;
> + dups = 0;
> + }
> +
> + if (!total_dups)
> + return total_dups;
> +
> + for (i = 0, j = 0; i < n_entries; i++) {
> + if (!sort_entries[i]->dup) {
> + sort_entries[j] = sort_entries[i];
> + if (j++ != i)
> + sort_entries[i] = NULL;
> + } else {
> + destroy_sort_entry(sort_entries[i]);
> + sort_entries[i] = NULL;
> + }
> + }
> +
> + return total_dups;
> +}
> +
> +static bool is_key(struct tracing_map *map, unsigned int field_idx)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < map->n_keys; i++)
> + if (map->key_idx[i] == field_idx)
> + return true;
> + return false;
> +}
> +
> +static void sort_secondary(struct tracing_map *map,
> + const struct tracing_map_sort_entry **entries,
> + unsigned int n_entries,
> + struct tracing_map_sort_key *primary_key,
> + struct tracing_map_sort_key *secondary_key)
> +{
> + int (*primary_fn)(const struct tracing_map_sort_entry **,
> + const struct tracing_map_sort_entry **);
> + int (*secondary_fn)(const struct tracing_map_sort_entry **,
> + const struct tracing_map_sort_entry **);
> + unsigned i, start = 0, n_sub = 1;
> +
> + if (is_key(map, primary_key->field_idx))
> + primary_fn = cmp_entries_key;
> + else
> + primary_fn = cmp_entries_sum;
> +
> + if (is_key(map, secondary_key->field_idx))
> + secondary_fn = cmp_entries_key;
> + else
> + secondary_fn = cmp_entries_sum;
> +
> + for (i = 0; i < n_entries - 1; i++) {
> + const struct tracing_map_sort_entry **a = &entries[i];
> + const struct tracing_map_sort_entry **b = &entries[i + 1];
> +
> + if (primary_fn(a, b) == 0) {
> + n_sub++;
> + if (i < n_entries - 2)
> + continue;
> + }
> +
> + if (n_sub < 2) {
> + start = i + 1;
> + n_sub = 1;
> + continue;
> + }
> +
> + set_sort_key(map, secondary_key);
> + sort(&entries[start], n_sub,
> + sizeof(struct tracing_map_sort_entry *),
> + (int (*)(const void *, const void *))secondary_fn, NULL);
> + set_sort_key(map, primary_key);
> +
> + start = i + 1;
> + n_sub = 1;
> + }
> +}
> +
> +/**
> + * tracing_map_sort_entries - Sort the current set of tracing_map_lts in a map
> + * @map: The tracing_map
> + * @sort_key: The sort key to use for sorting
> + * @sort_entries: outval: pointer to allocated and sorted array of entries
> + *
> + * tracing_map_sort_entries() sorts the current set of entries in the
> + * map and returns the list of tracing_map_sort_entries containing
> + * them to the client in the sort_entries param.
> + *
> + * The sort_key has only two fields: idx and descending. 'idx' refers
> + * to the index of the field added via tracing_map_add_sum_field() or
> + * tracing_map_add_key_field() when the tracing_map was initialized.
> + * 'descending' is a flag that if set reverses the sort order, which
> + * by default is ascending.
> + *
> + * The client should not hold on to the returned array but use it
> + * and call tracing_map_destroy_sort_entries() when done.
> + *
> + * Return: the number of sort_entries in the tracing_map_sort_entry
> + * array, negative on err
> + */
> +int tracing_map_sort_entries(struct tracing_map *map,
> + struct tracing_map_sort_key *sort_keys,
> + unsigned int n_sort_keys,
> + struct tracing_map_sort_entry ***sort_entries)
> +{
> + int (*cmp_entries_fn)(const struct tracing_map_sort_entry **,
> + const struct tracing_map_sort_entry **);
> + struct tracing_map_sort_entry *sort_entry, **entries;
> + int i, n_entries, ret;
> +
> + entries = kcalloc(map->max_elts, sizeof(sort_entry), GFP_KERNEL);
> + if (!entries)
> + return -ENOMEM;
> +
> + for (i = 0, n_entries = 0; i < map->map_size; i++) {
> + if (!map->map[i].key || !map->map[i].val)
> + continue;
> +
> + entries[n_entries] = create_sort_entry(map->map[i].val->key,
> + map->map[i].val);
> + if (!entries[n_entries++]) {
> + ret = -ENOMEM;
> + goto free;
> + }
> + }
> +
> + if (n_entries == 0) {
> + ret = 0;
> + goto free;
> + }
> +
> + if (n_entries == 1) {
> + *sort_entries = entries;
> + return 1;
> + }
> +
> + ret = merge_dups(entries, n_entries, map->key_size);
So this sorts.
> + if (ret < 0)
> + goto free;
> + n_entries -= ret;
> +
> + if (is_key(map, sort_keys[0].field_idx))
> + cmp_entries_fn = cmp_entries_key;
> + else
> + cmp_entries_fn = cmp_entries_sum;
> +
> + set_sort_key(map, &sort_keys[0]);
> +
> + sort(entries, n_entries, sizeof(struct tracing_map_sort_entry *),
> + (int (*)(const void *, const void *))cmp_entries_fn, NULL);
Then this sorts.
Why the double sort? Can't you just sort once, and then remove the dups?
-- Steve
> +
> + if (n_sort_keys > 1)
> + sort_secondary(map,
> + (const struct tracing_map_sort_entry **)entries,
> + n_entries,
> + &sort_keys[0],
> + &sort_keys[1]);
> +
> + *sort_entries = entries;
> +
> + return n_entries;
> + free:
> + tracing_map_destroy_sort_entries(entries, n_entries);
> +
> + return ret;
> +}
On Mon, 8 Jun 2015 16:32:05 -0500
Tom Zanussi <[email protected]> wrote:
> +/**
> + * tracing_map_init - Allocate and clear a map's tracing_map_elts
> + * @map: The tracing_map to initialize
> + *
> + * Creates and sets up a map to contain a max_size number of entries
> + * equal to a size of 2 ** map_bits. Before using, the map fields
> + * should be added to the map with tracing_map_add_key_field() and
> + * tracing_map_add_key_field(). tracing_map_init() should then be
Hmm, it's suppose to be added with tracing_map_add_key_field() twice?
-- Steve
> + * called to allocate the array of tracing_map_elts, in order to avoid
> + * allocating anything in the map insertion path. The user-specified
> + * map_size reflect the max number of entries requested by the user -
> + * internally we double that in order to keep the table sparse and
> + * keep collisions manageable.
> + *
> + * See tracing_map.h for a description of tracing_map_ops.
> + *
> + * Return: the tracing_map * if successful, ERR_PTR if not.
> + */
On 06/12/2015 06:01 PM, Steven Rostedt wrote:
>
> Why v3 in the subject?
This patch has not changed since v3 I guess.
>
> On Mon, 8 Jun 2015 16:32:00 -0500
> Tom Zanussi <[email protected]> wrote:
>
>> When a trigger is enabled, the cond flag should be set beforehand,
>> otherwise a trigger that's expecting to process a trace record
>> (e.g. one with post_trigger set) could be invoked without one.
>>
>> Likewise a trigger's cond flag should be reset after it's disabled,
>> not before.
>>
>> Signed-off-by: Tom Zanussi <[email protected]>
>> Signed-off-by: Daniel Wagner <[email protected]>
>
> Why is Daniel signed off by here?
I have reported the issue and send a fix for this patch
https://lkml.org/lkml/2015/4/21/161
I would have complained if I wasn't okay with it.
cheers,
daniel
On 06/13/2015 10:45 AM, Daniel Wagner wrote:
> On 06/12/2015 06:01 PM, Steven Rostedt wrote:
>>> Signed-off-by: Tom Zanussi <[email protected]>
>>> Signed-off-by: Daniel Wagner <[email protected]>
>>
>> Why is Daniel signed off by here?
>
> I have reported the issue and send a fix for this patch
>
> https://lkml.org/lkml/2015/4/21/161
>
> I would have complained if I wasn't okay with it.
Finally, have access to this account again. Let's do it proper:
Signed-off-by: Daniel Wagner <[email protected]>
On Fri, 2015-06-12 at 14:17 -0400, Steven Rostedt wrote:
> On Mon, 8 Jun 2015 16:32:05 -0500
> Tom Zanussi <[email protected]> wrote:
>
> > Add tracing_map, a special-purpose lock-free map for tracing.
> >
> > tracing_map is designed to aggregate or 'sum' one or more values
> > associated with a specific object of type tracing_map_elt, which
>
> What is "elt"? I don't see it explained anywhere.
>
It's short for 'element' but I guess that's not why you're asking about
it.
Sorry for the confusion - I've written up a description of the data
structures and how they work, which is included in my next revision.
Here's that section, from the new tracing_map.h:
/*
* This is an overview of the tracing_map data structures and how they
* relate to the tracing_map API. The details of the algorithms
* aren't discussed here - this is just a general overview of the data
* structures and how they interact with the API.
*
* The central data structure of the tracing_map is an initially
* zeroed array of struct tracing_map_entry (stored in the map field
* of struct tracing_map). tracing_map_entry is a very simple data
* structure containing only two fields: a 32-bit unsigned 'key'
* variable and a pointer named 'val'. This array of struct
* tracing_map_entry is essentially a hash table which will be
* modified by a single function, tracing_map_insert(), but which can
* be traversed and read by a user at any time (though the user does
* this indirectly via an array of tracing_map_sort_entry - see the
* explanation of that data structure in the discussion of the
* sorting-related data structures below).
*
* The central function of the tracing_map API is
* tracing_map_insert(). tracing_map_insert() hashes the
* arbitrarily-sized key passed into it into a 32-bit unsigned key.
* It then uses this key, truncated to the array size, as an index
* into the array of tracing_map_entries. If the value of the 'key'
* field of the tracing_map_entry found at that location is 0, then
* that entry is considered to be free and can be claimed, by
* replacing the 0 in the 'key' field of the tracing_map_entry with
* the new 32-bit hashed key. Once claimed, that tracing_map_entry's
* 'val' field is then used to store a unique element which will be
* forever associated with that 32-bit hashed key in the
* tracing_map_entry.
*
* That unique element now in the tracing_map_entry's 'val' field is
* an instance of tracing_map_elt, where 'elt' in the latter part of
* that variable name is short for 'element'. The purpose of a
* tracing_map_elt is to hold values specific to the the particular
* 32-bit hashed key it's assocated with. Things such as the unique
* set of aggregated sums associated with the 32-bit hashed key, along
* with a copy of the full key associated with the entry, and which
* was used to produce the 32-bit hashed key.
*
* When tracing_map_create() is called to create the tracing map, the
* user specifies (indirectly via the map_bits param, the details are
* unimportant for this discussion) the maximum number of elements
* that the map can hold (stored in the max_elts field of struct
* tracing_map). This is the maximum possible number of
* tracing_map_entries in the tracing_map_entry array which can be
* 'claimed' as described in the above discussion, and therefore is
* also the maximum number of tracing_map_elts that can be associated
* with the tracing_map_entry array in the tracing_map. Because of
* the way the insertion algorithm works, the size of the allocated
* tracing_map_entry array is always twice the maximum number of
* elements (2 * max_elts). This value is stored in the map_size
* field of struct tracing_map.
*
* Because tracing_map_insert() needs to work from any context,
* including from within the memory allocation functions themselves,
* both the tracing_map_entry array and a pool of max_elts
* tracing_map_elts are pre-allocated before any call is made to
* tracing_map_insert().
*
* The tracing_map_entry array is allocated as a single block by
* tracing_map_create().
*
* Because the tracing_map_elts are much larger objects and can't
* generally be allocated together as a single large array without
* failure, they're allocated individually, by tracing_map_init().
*
* The pool of tracing_map_elts are allocated by tracing_map_init()
* rather than by tracing_map_create() because at the time
* tracing_map_create() is called, there isn't enough information to
* create the tracing_map_elts. Specifically,the user first needs to
* tell the tracing_map implementation how many fields the
* tracing_map_elts contain, and which types of fields they are (key
* or sum). The user does this via the tracing_map_add_sum_field()
* and tracing_map_add_key_field() functions, following which the user
* calls tracing_map_init() to finish up the tracing map setup. The
* array holding the pointers which make up the pre-allocated pool of
* tracing_map_elts is allocated as a single block and is stored in
* the elts field of struct tracing_map.
*
* There is also a set of structures used for sorting that might
* benefit from some minimal explanation.
*
* struct tracing_map_sort_key is used to drive the sort at any given
* time. By 'any given time' we mean that a different
* tracing_map_sort_key will be used at different times depending on
* whether the sort currently being performed is a primary or a
* secondary sort.
*
* The sort key is very simple, consisting of the field index of the
* tracing_map_elt field to sort on (which the user saved when adding
* the field), and whether the sort should be done in an ascending or
* descending order.
*
* For the convenience of the sorting code, a tracing_map_sort_entry
* is created for each tracing_map_elt, again individually allocated
* to avoid failures that might be expected if allocated as a single
* large array of struct tracing_map_sort_entry.
* tracing_map_sort_entry instances are the objects expected by the
* various internal sorting functions, and are also what the user
* ultimately receives after calling tracing_map_sort_entries().
* Because it doesn't make sense for users to access an unordered and
* sparsely populated tracing_map directly, the
* tracing_map_sort_entries() function is provided so that users can
* retrieve a sorted list of all existing elements. In addition to
* the associated tracing_map_elt 'elt' field contained within the
* tracing_map_sort_entry, which is the object of interest to the
* user, tracing_map_sort_entry objects contain a number of additional
* fields which are used for caching and internal purposes and can
* safely be ignored.
*/
Thanks,
Tom
>
> > is associated by the map to a given key.
> >
> > It provides various hooks allowing per-tracer customization and is
> > separated out into a separate file in order to allow it to be shared
> > between multiple tracers, but isn't meant to be generally used outside
> > of that context.
> >
> > The tracing_map implementation was inspired by lock-free map
> > algorithms originated by Dr. Cliff Click:
> >
> > http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable
> > http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf
> >
> > Signed-off-by: Tom Zanussi <[email protected]>
>
>
> > +/**
> > + * tracing_map_update_sum - Add a value to a tracing_map_elt's sum
> > + * @elt: The tracing_map_elt
>
> Not a very useful comment, as I have no idea what "elt" is.
>
> I'll continue to review this patch about the mysterious element "elt".
>
> -- Steve
>
> > + * @i: The index of the given sum associated with the tracing_map_elt
> > + * @n: The value to add to the sum
> > + *
> > + * Add n to sum i associated with the specified tracing_map_elt
> > + * instance. The index i is the index returned by the call to
> > + * tracing_map_add_sum_field() when the tracing map was set up.
> > + */
> > +void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n)
> > +{
> > + atomic64_add(n, &elt->fields[i].sum);
> > +}
> > +
>
On Fri, 2015-06-12 at 14:01 -0400, Steven Rostedt wrote:
> Why v3 in the subject?
>
It was v3 of the patch he sent, which came at about v4 of the original
patchset. I guess that just causes confusion, so I'll keep the version
numbers the same for a patchset.
> On Mon, 8 Jun 2015 16:32:00 -0500
> Tom Zanussi <[email protected]> wrote:
>
> > When a trigger is enabled, the cond flag should be set beforehand,
> > otherwise a trigger that's expecting to process a trace record
> > (e.g. one with post_trigger set) could be invoked without one.
> >
> > Likewise a trigger's cond flag should be reset after it's disabled,
> > not before.
> >
> > Signed-off-by: Tom Zanussi <[email protected]>
> > Signed-off-by: Daniel Wagner <[email protected]>
>
> Why is Daniel signed off by here?
>
Daniel sent me the original problem report and attempt at a patch - I
started from that but fixed it up but still wanted to give him credit.
>From now on, I'll keep follow-ons separate (it's kind of unusual to have
people sending patches for patchsets still under review, so wasn't sure
about that).
Tom
> -- Steve
>
> > ---
> > kernel/trace/trace_events_trigger.c | 10 ++++++----
> > 1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
> > index 42a4009..4d2f3cc 100644
> > --- a/kernel/trace/trace_events_trigger.c
> > +++ b/kernel/trace/trace_events_trigger.c
> > @@ -543,11 +543,12 @@ static int register_trigger(char *glob, struct event_trigger_ops *ops,
> > list_add_rcu(&data->list, &file->triggers);
> > ret++;
> >
> > + update_cond_flag(file);
> > if (trace_event_trigger_enable_disable(file, 1) < 0) {
> > list_del_rcu(&data->list);
> > + update_cond_flag(file);
> > ret--;
> > }
> > - update_cond_flag(file);
> > out:
> > return ret;
> > }
> > @@ -575,8 +576,8 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
> > if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
> > unregistered = true;
> > list_del_rcu(&data->list);
> > - update_cond_flag(file);
> > trace_event_trigger_enable_disable(file, 0);
> > + update_cond_flag(file);
> > break;
> > }
> > }
> > @@ -1319,11 +1320,12 @@ static int event_enable_register_trigger(char *glob,
> > list_add_rcu(&data->list, &file->triggers);
> > ret++;
> >
> > + update_cond_flag(file);
> > if (trace_event_trigger_enable_disable(file, 1) < 0) {
> > list_del_rcu(&data->list);
> > + update_cond_flag(file);
> > ret--;
> > }
> > - update_cond_flag(file);
> > out:
> > return ret;
> > }
> > @@ -1344,8 +1346,8 @@ static void event_enable_unregister_trigger(char *glob,
> > (enable_data->file == test_enable_data->file)) {
> > unregistered = true;
> > list_del_rcu(&data->list);
> > - update_cond_flag(file);
> > trace_event_trigger_enable_disable(file, 0);
> > + update_cond_flag(file);
> > break;
> > }
> > }
>
On Fri, 2015-06-12 at 16:52 -0400, Steven Rostedt wrote:
> On Mon, 8 Jun 2015 16:32:05 -0500
> Tom Zanussi <[email protected]> wrote:
>
> > +/**
> > + * tracing_map_init - Allocate and clear a map's tracing_map_elts
> > + * @map: The tracing_map to initialize
> > + *
> > + * Creates and sets up a map to contain a max_size number of entries
> > + * equal to a size of 2 ** map_bits. Before using, the map fields
> > + * should be added to the map with tracing_map_add_key_field() and
> > + * tracing_map_add_key_field(). tracing_map_init() should then be
>
> Hmm, it's suppose to be added with tracing_map_add_key_field() twice?
>
Also fixed in the new version, coming shortly, thanks for the input.
Tom
> -- Steve
>
> > + * called to allocate the array of tracing_map_elts, in order to avoid
> > + * allocating anything in the map insertion path. The user-specified
> > + * map_size reflect the max number of entries requested by the user -
> > + * internally we double that in order to keep the table sparse and
> > + * keep collisions manageable.
> > + *
> > + * See tracing_map.h for a description of tracing_map_ops.
> > + *
> > + * Return: the tracing_map * if successful, ERR_PTR if not.
> > + */