Changes in v2:
- renamed resume and pause commands to enable and disable ones, renamed
CTL_CMD_RESUME and CTL_CMD_PAUSE to CTL_CMD_ENABLE and CTL_CMD_DISABLE
to fit to the appropriate ioctls and avoid mixing up with PAUSE_OUTPUT
ioctl;
- factored out event handling loop into a handle_events() for stat mode;
- separated -D,--delay=-1 into separate patches for stat and record modes;
v1: https://lore.kernel.org/lkml/[email protected]/
repo: tip of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git perf/core
The patch set implements handling of 'start disabled', 'enable' and 'disable'
external control commands which can be provided for stat and record modes
of the tool from an external controlling process. 'start disabled' command
can be used to postpone enabling of events in the beginning of a monitoring
session. 'enable' and 'disable' commands can be used to enable and disable
events correspondingly any time after the start of the session.
The 'start disabled', 'enable' and 'disable' external control commands can be
used to focus measurement on specially selected time intervals of workload
execution. Focused measurement reduces tool intrusion and influence on
workload behavior, reduces distortion and amount of collected and stored
data, mitigates data accuracy loss because measurement and data capturing
happen only during intervals of interest.
A controlling process can be a bash shell script [1], native executable or
any other language program that can directly work with file descriptors,
e.g. pipes [2], and spawn a process, specially the tool one.
-D,--delay <val> option is extended with -1 value to skip events enabling
in the beginning of a monitoring session ('start disabled' command). --ctl-fd
and --ctl-fd-ack command line options are introduced to provide the tool
with a pair of file descriptors to listen to control commands and reply to
the controlling process on the completion of received commands.
The tool reads two byte control command message from ctl-fd descriptor,
handles the command and optionally replies two bytes acknowledgement message
to fd-ack descriptor, if it is specified on the command line. 'enable'
command is recognized as 'e' character message and 'disable' command is
recognized as 'd' character message both received from ctl-fd descriptor.
Completion message is 'a''\n' and sent to fd-ack descriptor.
example bash script demonstrating simple use case:
#!/bin/bash
ctl_dir=/tmp/
ctl_fifo=${ctl_dir}perf_ctl.fifo
test -p ${ctl_fifo} && unlink ${ctl_fifo}
mkfifo ${ctl_fifo} && exec {ctl_fd}<>${ctl_fifo}
ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
mkfifo ${ctl_ack_fifo} && exec {ctl_fd_ack}<>${ctl_ack_fifo}
perf stat -D -1 -e cpu-cycles -a -I 1000 \
--ctl-fd ${ctl_fd} --ctl-fd-ack ${ctl_fd_ack} \
-- sleep 40 &
perf_pid=$!
sleep 5 && echo 'e' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"
sleep 10 && echo 'd' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"
sleep 5 && echo 'e' >&${ctl_fd} && read -u ${ctl_fd_ack} e2 && echo "enabled(${e2})"
sleep 10 && echo 'd' >&${ctl_fd} && read -u ${ctl_fd_ack} d2 && echo "disabled(${d2})"
exec {ctl_fd_ack}>&- && unlink ${ctl_ack_fifo}
exec {ctl_fd}>&- && unlink ${ctl_fifo}
wait -n ${perf_pid}
exit $?
Script output:
[root@host acme] example
Events disabled
# time counts unit events
1.001101062 <not counted> cpu-cycles
2.002994944 <not counted> cpu-cycles
3.004864340 <not counted> cpu-cycles
4.006727177 <not counted> cpu-cycles
Events enabled
enabled(a)
4.993808464 3,124,246 cpu-cycles
5.008597004 3,325,624 cpu-cycles
6.010387483 83,472,992 cpu-cycles
7.012266598 55,877,621 cpu-cycles
8.014175695 97,892,729 cpu-cycles
9.016056093 68,461,242 cpu-cycles
10.017937507 55,449,643 cpu-cycles
11.019830154 68,938,167 cpu-cycles
12.021719952 55,164,101 cpu-cycles
13.023627550 70,535,720 cpu-cycles
14.025580995 53,240,125 cpu-cycles
disabled(a)
14.997518260 53,558,068 cpu-cycles
Events disabled
15.027216416 <not counted> cpu-cycles
16.029052729 <not counted> cpu-cycles
17.030904762 <not counted> cpu-cycles
18.032073424 <not counted> cpu-cycles
19.033805074 <not counted> cpu-cycles
Events enabled
enabled(a)
20.001279097 3,021,022 cpu-cycles
20.035044381 6,434,367 cpu-cycles
21.036923813 89,358,251 cpu-cycles
22.038825169 72,516,351 cpu-cycles
# time counts unit events
23.040715596 55,046,157 cpu-cycles
24.042643757 78,128,649 cpu-cycles
25.044558535 61,052,428 cpu-cycles
26.046452785 62,142,806 cpu-cycles
27.048353021 74,477,971 cpu-cycles
28.050241286 61,001,623 cpu-cycles
29.052149961 61,653,502 cpu-cycles
disabled(a)
30.004980264 82,729,640 cpu-cycles
Events disabled
30.053516176 <not counted> cpu-cycles
31.055348366 <not counted> cpu-cycles
32.057202097 <not counted> cpu-cycles
33.059040702 <not counted> cpu-cycles
34.060843288 <not counted> cpu-cycles
35.000888624 <not counted> cpu-cycles
[root@host acme]#
[1] http://man7.org/linux/man-pages/man1/bash.1.html
[2] http://man7.org/linux/man-pages/man2/pipe.2.html
---
Alexey Budankov (11):
perf evlist: introduce control file descriptors
perf evlist: implement control command handling functions
perf stat: factor out event handling loop into a function
perf stat: extend -D,--delay option with -1 value
perf stat: implement control commands handling
perf stat: introduce --ctl-fd[-ack] options
perf docs: extend stat mode docs with info on --ctl-fd[-ack] options
perf record: extend -D,--delay option with -1 value
perf record: implement control commands handling
perf record: introduce --ctl-fd[-ack] options
perf docs: extend record mode docs with info on --ctl-fd[-ack] options
tools/perf/Documentation/perf-record.txt | 39 +++++++
tools/perf/Documentation/perf-stat.txt | 40 +++++++
tools/perf/builtin-record.c | 39 ++++++-
tools/perf/builtin-stat.c | 137 ++++++++++++++++-------
tools/perf/builtin-trace.c | 2 +-
tools/perf/util/evlist.c | 103 +++++++++++++++++
tools/perf/util/evlist.h | 18 +++
tools/perf/util/record.h | 4 +-
tools/perf/util/stat.h | 4 +-
9 files changed, 339 insertions(+), 47 deletions(-)
--
2.24.1
Implement functions of initialization, finalization and processing
of control commands coming from control file descriptors.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/util/evlist.c | 100 +++++++++++++++++++++++++++++++++++++++
tools/perf/util/evlist.h | 12 +++++
2 files changed, 112 insertions(+)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 2db4bedc4f81..e086c846ef3a 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1707,3 +1707,103 @@ struct evsel *perf_evlist__reset_weak_group(struct evlist *evsel_list,
}
return leader;
}
+
+int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack)
+{
+ if (ctl_fd == -1) {
+ pr_debug("Control descriptor is not initialized\n");
+ return 0;
+ }
+
+ evlist->ctl_fd_pos = perf_evlist__add_pollfd(&evlist->core, ctl_fd, NULL, POLLIN);
+ if (evlist->ctl_fd_pos < 0) {
+ evlist->ctl_fd_pos = -1;
+ pr_err("Failed to add ctl fd entry: %m\n");
+ return -1;
+ }
+
+ evlist->ctl_fd = ctl_fd;
+ evlist->ctl_fd_ack = ctl_fd_ack;
+
+ return 0;
+}
+
+int perf_evlist__finalize_ctlfd(struct evlist *evlist)
+{
+ if (evlist->ctl_fd_pos == -1)
+ return 0;
+
+ evlist->core.pollfd.entries[evlist->ctl_fd_pos].fd = -1;
+ evlist->ctl_fd_pos = -1;
+ evlist->ctl_fd_ack = -1;
+ evlist->ctl_fd = -1;
+
+ return 0;
+}
+
+static int perf_evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
+{
+ int err;
+ char buf[2];
+
+ err = read(evlist->ctl_fd, &buf, sizeof(buf));
+ if (err > 0)
+ *cmd = buf[0];
+ else if (err == -1)
+ pr_err("Failed to read from ctlfd %d: %m\n", evlist->ctl_fd);
+
+ return err;
+}
+
+static int perf_evlist__ctlfd_ack(struct evlist *evlist)
+{
+ int err;
+ char buf[2] = {CTL_CMD_ACK, '\n'};
+
+ if (evlist->ctl_fd_ack == -1)
+ return 0;
+
+ err = write(evlist->ctl_fd_ack, buf, sizeof(buf));
+ if (err == -1)
+ pr_err("failed to write to ctl_ack_fd %d: %m\n", evlist->ctl_fd_ack);
+
+ return err;
+}
+
+int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
+{
+ int err = 0;
+ int ctlfd_pos = evlist->ctl_fd_pos;
+ struct pollfd *entries = evlist->core.pollfd.entries;
+
+ if (!entries[ctlfd_pos].revents)
+ return 0;
+
+ if (entries[ctlfd_pos].revents & POLLIN) {
+ err = perf_evlist__ctlfd_recv(evlist, cmd);
+ if (err > 0) {
+ switch (*cmd) {
+ case CTL_CMD_ENABLE:
+ evlist__enable(evlist);
+ break;
+ case CTL_CMD_DISABLE:
+ evlist__disable(evlist);
+ break;
+ case CTL_CMD_ACK:
+ case CTL_CMD_UNSUPPORTED:
+ default:
+ pr_debug("ctlfd: unsupported %d\n", *cmd);
+ break;
+ }
+ if (!(*cmd == CTL_CMD_ACK || *cmd == CTL_CMD_UNSUPPORTED))
+ perf_evlist__ctlfd_ack(evlist);
+ }
+ }
+
+ if (entries[ctlfd_pos].revents & (POLLHUP | POLLERR))
+ perf_evlist__finalize_ctlfd(evlist);
+ else
+ entries[ctlfd_pos].revents = 0;
+
+ return err;
+}
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 62f259d89b41..84386850c290 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -358,4 +358,16 @@ void perf_evlist__force_leader(struct evlist *evlist);
struct evsel *perf_evlist__reset_weak_group(struct evlist *evlist,
struct evsel *evsel,
bool close);
+
+enum evlist_ctl_cmd {
+ CTL_CMD_UNSUPPORTED = 0,
+ CTL_CMD_ENABLE = 'e',
+ CTL_CMD_DISABLE = 'd',
+ CTL_CMD_ACK = 'a'
+};
+
+int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
+int perf_evlist__finalize_ctlfd(struct evlist *evlist);
+int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
+
#endif /* __PERF_EVLIST_H */
--
2.24.1
Define and initialize control file descriptors.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/util/evlist.c | 3 +++
tools/perf/util/evlist.h | 3 +++
2 files changed, 6 insertions(+)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 0a0b760d6948..2db4bedc4f81 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -63,6 +63,9 @@ void evlist__init(struct evlist *evlist, struct perf_cpu_map *cpus,
perf_evlist__set_maps(&evlist->core, cpus, threads);
evlist->workload.pid = -1;
evlist->bkw_mmap_state = BKW_MMAP_NOTREADY;
+ evlist->ctl_fd = -1;
+ evlist->ctl_fd_ack = -1;
+ evlist->ctl_fd_pos = -1;
}
struct evlist *evlist__new(void)
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index b6f325dfb4d2..62f259d89b41 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -74,6 +74,9 @@ struct evlist {
pthread_t th;
volatile int done;
} thread;
+ int ctl_fd;
+ int ctl_fd_ack;
+ int ctl_fd_pos;
};
struct evsel_str_handler {
--
2.24.1
Factor out event handling loop into handle_events() function.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/builtin-stat.c | 85 +++++++++++++++++++++++----------------
1 file changed, 50 insertions(+), 35 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index e0c1ad23c768..9775b0905146 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -371,6 +371,16 @@ static void process_interval(void)
print_counters(&rs, 0, NULL);
}
+static bool print_interval_and_stop(struct perf_stat_config *config, int *times)
+{
+ if (config->interval) {
+ process_interval();
+ if (interval_count && !(--(*times)))
+ return true;
+ }
+ return false;
+}
+
static void enable_counters(void)
{
if (stat_config.initial_delay)
@@ -436,6 +446,42 @@ static bool is_target_alive(struct target *_target,
return false;
}
+static int handle_events(pid_t pid, struct perf_stat_config *config)
+{
+ pid_t child = 0;
+ bool res, stop = false;
+ struct timespec time_to_sleep;
+ int sleep_time, status = 0, times = config->times;
+
+ if (config->interval)
+ sleep_time = config->interval;
+ else if (config->timeout)
+ sleep_time = config->timeout;
+ else
+ sleep_time = 1000;
+
+ time_to_sleep.tv_sec = sleep_time / MSEC_PER_SEC;
+ time_to_sleep.tv_nsec = (sleep_time % MSEC_PER_SEC) * NSEC_PER_MSEC;
+
+ do {
+ if (pid != -1)
+ child = waitpid(pid, &status, WNOHANG);
+ if (child || stop || done)
+ break;
+ nanosleep(&time_to_sleep, NULL);
+ if (pid == -1)
+ stop = !is_target_alive(&target, evsel_list->core.threads);
+ if (config->timeout) {
+ stop = !stop ? true : stop;
+ } else {
+ res = print_interval_and_stop(config, ×);
+ stop = !stop ? res : stop;
+ }
+ } while (1);
+
+ return status;
+}
+
enum counter_recovery {
COUNTER_SKIP,
COUNTER_RETRY,
@@ -494,12 +540,10 @@ static enum counter_recovery stat_handle_error(struct evsel *counter)
static int __run_perf_stat(int argc, const char **argv, int run_idx)
{
int interval = stat_config.interval;
- int times = stat_config.times;
int timeout = stat_config.timeout;
char msg[BUFSIZ];
unsigned long long t0, t1;
struct evsel *counter;
- struct timespec ts;
size_t l;
int status = 0;
const bool forks = (argc > 0);
@@ -508,17 +552,6 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
int i, cpu;
bool second_pass = false;
- if (interval) {
- ts.tv_sec = interval / USEC_PER_MSEC;
- ts.tv_nsec = (interval % USEC_PER_MSEC) * NSEC_PER_MSEC;
- } else if (timeout) {
- ts.tv_sec = timeout / USEC_PER_MSEC;
- ts.tv_nsec = (timeout % USEC_PER_MSEC) * NSEC_PER_MSEC;
- } else {
- ts.tv_sec = 1;
- ts.tv_nsec = 0;
- }
-
if (forks) {
if (perf_evlist__prepare_workload(evsel_list, &target, argv, is_pipe,
workload_exec_failed_signal) < 0) {
@@ -675,16 +708,9 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
perf_evlist__start_workload(evsel_list);
enable_counters();
- if (interval || timeout) {
- while (!waitpid(child_pid, &status, WNOHANG)) {
- nanosleep(&ts, NULL);
- if (timeout)
- break;
- process_interval();
- if (interval_count && !(--times))
- break;
- }
- }
+ if (interval || timeout)
+ handle_events(child_pid, &stat_config);
+
if (child_pid != -1) {
if (timeout)
kill(child_pid, SIGTERM);
@@ -701,18 +727,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
psignal(WTERMSIG(status), argv[0]);
} else {
enable_counters();
- while (!done) {
- nanosleep(&ts, NULL);
- if (!is_target_alive(&target, evsel_list->core.threads))
- break;
- if (timeout)
- break;
- if (interval) {
- process_interval();
- if (interval_count && !(--times))
- break;
- }
- }
+ handle_events(-1, &stat_config);
}
disable_counters();
--
2.24.1
Extend -D,--delay option with -1 value to start monitoring with
events disabled to be enabled later by enable command provided
via control file descriptor.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/builtin-stat.c | 18 ++++++++++++++----
tools/perf/util/evlist.h | 3 +++
tools/perf/util/stat.h | 2 +-
3 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 9775b0905146..bda777ca0420 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -383,16 +383,26 @@ static bool print_interval_and_stop(struct perf_stat_config *config, int *times)
static void enable_counters(void)
{
- if (stat_config.initial_delay)
+ if (stat_config.initial_delay < 0) {
+ pr_info(PERF_EVLIST__DISABLED_MSG);
+ return;
+ }
+
+ if (stat_config.initial_delay > 0) {
+ pr_info(PERF_EVLIST__DISABLED_MSG);
usleep(stat_config.initial_delay * USEC_PER_MSEC);
+ }
/*
* We need to enable counters only if:
* - we don't have tracee (attaching to task or cpu)
* - we have initial delay configured
*/
- if (!target__none(&target) || stat_config.initial_delay)
+ if (!target__none(&target) || stat_config.initial_delay) {
evlist__enable(evsel_list);
+ if (stat_config.initial_delay > 0)
+ pr_info(PERF_EVLIST__ENABLED_MSG);
+ }
}
static void disable_counters(void)
@@ -929,8 +939,8 @@ static struct option stat_options[] = {
"aggregate counts per thread", AGGR_THREAD),
OPT_SET_UINT(0, "per-node", &stat_config.aggr_mode,
"aggregate counts per numa node", AGGR_NODE),
- OPT_UINTEGER('D', "delay", &stat_config.initial_delay,
- "ms to wait before starting measurement after program start"),
+ OPT_INTEGER('D', "delay", &stat_config.initial_delay,
+ "ms to wait before starting measurement after program start (-1: start with events disabled"),
OPT_CALLBACK_NOOPT(0, "metric-only", &stat_config.metric_only, NULL,
"Only print computed metrics. No raw values", enable_metric_only),
OPT_BOOLEAN(0, "topdown", &topdown_run,
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 84386850c290..874ecf068ac9 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -366,6 +366,9 @@ enum evlist_ctl_cmd {
CTL_CMD_ACK = 'a'
};
+#define PERF_EVLIST__ENABLED_MSG "Events enabled\n"
+#define PERF_EVLIST__DISABLED_MSG "Events disabled\n"
+
int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
int perf_evlist__finalize_ctlfd(struct evlist *evlist);
int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index b4fdfaa7f2c0..027b9dcd902f 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -113,7 +113,7 @@ struct perf_stat_config {
FILE *output;
unsigned int interval;
unsigned int timeout;
- unsigned int initial_delay;
+ int initial_delay;
unsigned int unit_width;
unsigned int metric_only_len;
int times;
--
2.24.1
Introduce --ctl-fd[-ack] options to pass open file descriptors
numbers from command line.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/builtin-stat.c | 10 ++++++++++
tools/perf/util/stat.h | 2 ++
2 files changed, 12 insertions(+)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 5aab3ff1bbea..60c0d9521f74 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -187,6 +187,8 @@ static struct perf_stat_config stat_config = {
.metric_only_len = METRIC_ONLY_LEN,
.walltime_nsecs_stats = &walltime_nsecs_stats,
.big_num = true,
+ .ctl_fd = -1,
+ .ctl_fd_ack = -1
};
static inline void diff_timespec(struct timespec *r, struct timespec *a,
@@ -984,6 +986,10 @@ static struct option stat_options[] = {
"Use with 'percore' event qualifier to show the event "
"counts of one hardware thread by sum up total hardware "
"threads of same physical core"),
+ OPT_INTEGER(0, "ctl-fd", &stat_config.ctl_fd,
+ "Listen on fd descriptor for command to control measurement ('e': enable events, 'd': disable events)"),
+ OPT_INTEGER(0, "ctl-fd-ack", &stat_config.ctl_fd_ack,
+ "Send control command completion ('a') to fd ack descriptor"),
OPT_END()
};
@@ -2180,6 +2186,8 @@ int cmd_stat(int argc, const char **argv)
signal(SIGALRM, skip_signal);
signal(SIGABRT, skip_signal);
+ perf_evlist__initialize_ctlfd(evsel_list, stat_config.ctl_fd, stat_config.ctl_fd_ack);
+
status = 0;
for (run_idx = 0; forever || run_idx < stat_config.run_count; run_idx++) {
if (stat_config.run_count != 1 && verbose > 0)
@@ -2199,6 +2207,8 @@ int cmd_stat(int argc, const char **argv)
if (!forever && status != -1 && !interval)
print_counters(NULL, argc, argv);
+ perf_evlist__finalize_ctlfd(evsel_list);
+
if (STAT_RECORD) {
/*
* We synthesize the kernel mmap record just so that older tools
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index 027b9dcd902f..0b0fa3a2cde2 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -130,6 +130,8 @@ struct perf_stat_config {
struct perf_cpu_map *cpus_aggr_map;
u64 *walltime_run;
struct rblist metric_events;
+ int ctl_fd;
+ int ctl_fd_ack;
};
void update_stats(struct stats *stats, u64 val);
--
2.24.1
Extend perf-stat.txt file with --ctl-fd[-ack] options description.
Document possible usage model introduced by --ctl-fd[-ack] options
by providing example bash shell script.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/Documentation/perf-stat.txt | 40 ++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 3fb5028aef08..19ed53e08294 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -164,6 +164,46 @@ with it. --append may be used here. Examples:
3>results perf stat --log-fd 3 -- $cmd
3>>results perf stat --log-fd 3 --append -- $cmd
+--ctl-fd::
+--ctl-fd-ack::
+
+Listen on ctl-fd descriptor for command to control measurement ('e': enable events,
+'d': disable events). Optionally send control command completion ('a') to fd-ack
+descriptor to synchronize with the controlling process. Example of bash shell script
+to enable and disable events during measurements:
+
+#!/bin/bash
+
+ctl_dir=/tmp/
+
+ctl_fifo=${ctl_dir}perf_ctl.fifo
+test -p ${ctl_fifo} && unlink ${ctl_fifo}
+mkfifo ${ctl_fifo}
+exec {ctl_fd}<>${ctl_fifo}
+
+ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
+test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
+mkfifo ${ctl_ack_fifo}
+exec {ctl_fd_ack}<>${ctl_ack_fifo}
+
+perf stat -D -1 -e cpu-cycles -a -I 1000 \
+ --ctl-fd ${ctl_fd} --ctl-fd-ack ${ctl_fd_ack} \
+ -- sleep 30 &
+perf_pid=$!
+
+sleep 5 && echo 'e' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"
+sleep 10 && echo 'd' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"
+
+exec {ctl_fd_ack}>&-
+unlink ${ctl_ack_fifo}
+
+exec {ctl_fd}>&-
+unlink ${ctl_fifo}
+
+wait -n ${perf_pid}
+exit $?
+
+
--pre::
--post::
Pre and post measurement hooks, e.g.:
--
2.24.1
Implement handling of 'enable' and 'disable' control commands
coming from control file descriptor.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/builtin-record.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 8a14e68b86ad..2278a3efc747 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1496,6 +1496,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
bool disabled = false, draining = false;
int fd;
float ratio = 0;
+ enum evlist_ctl_cmd cmd = CTL_CMD_UNSUPPORTED;
atexit(record__sig_exit);
signal(SIGCHLD, sig_handler);
@@ -1793,8 +1794,23 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
* Propagate error, only if there's any. Ignore positive
* number of returned events and interrupt error.
*/
- if (err > 0 || (err < 0 && errno == EINTR))
+ if (err > 0 || (err < 0 && errno == EINTR)) {
err = 0;
+ if (perf_evlist__ctlfd_process(rec->evlist, &cmd) > 0) {
+ switch (cmd) {
+ case CTL_CMD_ENABLE:
+ pr_info(PERF_EVLIST__ENABLED_MSG);
+ break;
+ case CTL_CMD_DISABLE:
+ pr_info(PERF_EVLIST__DISABLED_MSG);
+ break;
+ case CTL_CMD_ACK:
+ case CTL_CMD_UNSUPPORTED:
+ default:
+ break;
+ }
+ }
+ }
waking++;
if (evlist__filter_pollfd(rec->evlist, POLLERR | POLLHUP) == 0)
--
2.24.1
Introduce --ctl-fd[-ack] options to pass open file descriptors
numbers from command line.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/builtin-record.c | 9 +++++++++
tools/perf/util/record.h | 2 ++
2 files changed, 11 insertions(+)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 2278a3efc747..9cf738ff1cae 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1704,6 +1704,8 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
perf_evlist__start_workload(rec->evlist);
}
+ perf_evlist__initialize_ctlfd(rec->evlist, opts->ctl_fd, opts->ctl_fd_ack);
+
if (opts->initial_delay) {
pr_info(PERF_EVLIST__DISABLED_MSG);
if (opts->initial_delay > 0) {
@@ -1850,6 +1852,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
record__synthesize_workload(rec, true);
out_child:
+ perf_evlist__finalize_ctlfd(rec->evlist);
record__mmap_read_all(rec, true);
record__aio_mmap_read_sync(rec);
@@ -2331,6 +2334,8 @@ static struct record record = {
},
.mmap_flush = MMAP_FLUSH_DEFAULT,
.nr_threads_synthesize = 1,
+ .ctl_fd = -1,
+ .ctl_fd_ack = -1,
},
.tool = {
.sample = process_sample_event,
@@ -2526,6 +2531,10 @@ static struct option __record_options[] = {
OPT_UINTEGER(0, "num-thread-synthesize",
&record.opts.nr_threads_synthesize,
"number of threads to run for event synthesis"),
+ OPT_INTEGER(0, "ctl-fd", &record.opts.ctl_fd,
+ "Listen on fd descriptor for command to control measurement ('e': enable events, 'd': disable events)"),
+ OPT_INTEGER(0, "ctl-fd-ack", &record.opts.ctl_fd_ack,
+ "Send control command completion ('a') to fd ack descriptor"),
OPT_END()
};
diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h
index 96a73bbd8cd4..da18aeca3623 100644
--- a/tools/perf/util/record.h
+++ b/tools/perf/util/record.h
@@ -69,6 +69,8 @@ struct record_opts {
int mmap_flush;
unsigned int comp_level;
unsigned int nr_threads_synthesize;
+ int ctl_fd;
+ int ctl_fd_ack;
};
extern const char * const *record_usage;
--
2.24.1
Extend perf-record.txt file with --ctl-fd[-ack] options description.
Document possible usage model introduced by --ctl-fd[-ack] options
by providing example bash shell script.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/Documentation/perf-record.txt | 39 ++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 561ef55743e2..eabb00ed2f5d 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -613,6 +613,45 @@ appended unit character - B/K/M/G
The number of threads to run when synthesizing events for existing processes.
By default, the number of threads equals 1.
+--ctl-fd::
+--ctl-fd-ack::
+Listen on ctl-fd descriptor for command to control measurement ('e': enable events,
+'d': disable events. Optionally send control command completion ('a') to fd-ack
+descriptor to synchronize with the controlling process. Example of bash shell script
+to enable and disable events during measurements:
+
+#!/bin/bash
+
+ctl_dir=/tmp/
+
+ctl_fifo=${ctl_dir}perf_ctl.fifo
+test -p ${ctl_fifo} && unlink ${ctl_fifo}
+mkfifo ${ctl_fifo}
+exec {ctl_fd}<>${ctl_fifo}
+
+ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
+test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
+mkfifo ${ctl_ack_fifo}
+exec {ctl_fd_ack}<>${ctl_ack_fifo}
+
+perf record -D -1 -e cpu-cycles -a \
+ --ctl-fd ${ctl_fd} --ctl-fd-ack ${ctl_fd_ack} \
+ -- sleep 30 &
+perf_pid=$!
+
+sleep 5 && echo 'e' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "resumed(${e1})"
+sleep 10 && echo 'd' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "paused(${d1})"
+
+exec {ctl_fd_ack}>&-
+unlink ${ctl_ack_fifo}
+
+exec {ctl_fd}>&-
+unlink ${ctl_fifo}
+
+wait -n ${perf_pid}
+exit $?
+
+
SEE ALSO
--------
linkperf:perf-stat[1], linkperf:perf-list[1], linkperf:perf-intel-pt[1]
--
2.24.1
Implement handling of 'enable' and 'disable' control commands
coming from control file descriptor.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/builtin-stat.c | 48 +++++++++++++++++++++++++++++----------
1 file changed, 36 insertions(+), 12 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index bda777ca0420..5aab3ff1bbea 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -460,8 +460,9 @@ static int handle_events(pid_t pid, struct perf_stat_config *config)
{
pid_t child = 0;
bool res, stop = false;
- struct timespec time_to_sleep;
- int sleep_time, status = 0, times = config->times;
+ int time_to_sleep, sleep_time, status = 0, times = config->times;
+ enum evlist_ctl_cmd cmd = CTL_CMD_UNSUPPORTED;
+ struct timespec time_start, time_stop, time_diff;
if (config->interval)
sleep_time = config->interval;
@@ -470,22 +471,45 @@ static int handle_events(pid_t pid, struct perf_stat_config *config)
else
sleep_time = 1000;
- time_to_sleep.tv_sec = sleep_time / MSEC_PER_SEC;
- time_to_sleep.tv_nsec = (sleep_time % MSEC_PER_SEC) * NSEC_PER_MSEC;
+ time_to_sleep = sleep_time;
do {
if (pid != -1)
child = waitpid(pid, &status, WNOHANG);
if (child || stop || done)
break;
- nanosleep(&time_to_sleep, NULL);
- if (pid == -1)
- stop = !is_target_alive(&target, evsel_list->core.threads);
- if (config->timeout) {
- stop = !stop ? true : stop;
- } else {
- res = print_interval_and_stop(config, ×);
- stop = !stop ? res : stop;
+ clock_gettime(CLOCK_MONOTONIC, &time_start);
+ if (!(evlist__poll(evsel_list, time_to_sleep) > 0)) { /* poll timeout or EINTR */
+ if (pid == -1)
+ stop = !is_target_alive(&target, evsel_list->core.threads);
+ if (config->timeout) {
+ stop = !stop ? true : stop;
+ } else {
+ res = print_interval_and_stop(config, ×);
+ stop = !stop ? res : stop;
+ }
+ time_to_sleep = sleep_time;
+ } else { /* fd revent */
+ if (perf_evlist__ctlfd_process(evsel_list, &cmd) > 0) {
+ switch (cmd) {
+ case CTL_CMD_ENABLE:
+ pr_info(PERF_EVLIST__ENABLED_MSG);
+ stop = print_interval_and_stop(config, ×);
+ break;
+ case CTL_CMD_DISABLE:
+ stop = print_interval_and_stop(config, ×);
+ pr_info(PERF_EVLIST__DISABLED_MSG);
+ break;
+ case CTL_CMD_ACK:
+ case CTL_CMD_UNSUPPORTED:
+ default:
+ break;
+ }
+ }
+ clock_gettime(CLOCK_MONOTONIC, &time_stop);
+ diff_timespec(&time_diff, &time_stop, &time_start);
+ time_to_sleep -= time_diff.tv_sec * MSEC_PER_SEC +
+ time_diff.tv_nsec / NSEC_PER_MSEC;
}
} while (1);
--
2.24.1
Extend -D,--delay option with -1 to start collection
with events disabled to be enbled later by enable
command provided via control file descriptor.
Signed-off-by: Alexey Budankov <[email protected]>
---
tools/perf/builtin-record.c | 12 ++++++++----
tools/perf/builtin-trace.c | 2 +-
tools/perf/util/record.h | 2 +-
3 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index e4efdbf1a81e..8a14e68b86ad 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1704,8 +1704,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
}
if (opts->initial_delay) {
- usleep(opts->initial_delay * USEC_PER_MSEC);
- evlist__enable(rec->evlist);
+ pr_info(PERF_EVLIST__DISABLED_MSG);
+ if (opts->initial_delay > 0) {
+ usleep(opts->initial_delay * USEC_PER_MSEC);
+ evlist__enable(rec->evlist);
+ pr_info(PERF_EVLIST__ENABLED_MSG);
+ }
}
trigger_ready(&auxtrace_snapshot_trigger);
@@ -2413,8 +2417,8 @@ static struct option __record_options[] = {
OPT_CALLBACK('G', "cgroup", &record.evlist, "name",
"monitor event in cgroup name only",
parse_cgroups),
- OPT_UINTEGER('D', "delay", &record.opts.initial_delay,
- "ms to wait before starting measurement after program start"),
+ OPT_INTEGER('D', "delay", &record.opts.initial_delay,
+ "ms to wait before starting measurement after program start (-1: start with events disabled )"),
OPT_BOOLEAN(0, "kcore", &record.opts.kcore, "copy /proc/kcore"),
OPT_STRING('u', "uid", &record.opts.target.uid_str, "user",
"user to profile"),
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index a46efb907bd4..63f69a927f3c 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -4773,7 +4773,7 @@ int cmd_trace(int argc, const char **argv)
"per thread proc mmap processing timeout in ms"),
OPT_CALLBACK('G', "cgroup", &trace, "name", "monitor event in cgroup name only",
trace__parse_cgroups),
- OPT_UINTEGER('D', "delay", &trace.opts.initial_delay,
+ OPT_INTEGER('D', "delay", &trace.opts.initial_delay,
"ms to wait before starting measurement after program "
"start"),
OPTS_EVSWITCH(&trace.evswitch),
diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h
index 923565c3b155..96a73bbd8cd4 100644
--- a/tools/perf/util/record.h
+++ b/tools/perf/util/record.h
@@ -60,7 +60,7 @@ struct record_opts {
const char *auxtrace_snapshot_opts;
const char *auxtrace_sample_opts;
bool sample_transaction;
- unsigned initial_delay;
+ int initial_delay;
bool use_clockid;
clockid_t clockid;
u64 clockid_res_ns;
--
2.24.1
Em Wed, May 06, 2020 at 09:22:55PM +0300, Alexey Budankov escreveu:
>
> Extend perf-stat.txt file with --ctl-fd[-ack] options description.
> Document possible usage model introduced by --ctl-fd[-ack] options
> by providing example bash shell script.
Please update the docs in the same patch that introduces the options
being documented.
- Arnaldo
> Signed-off-by: Alexey Budankov <[email protected]>
> ---
> tools/perf/Documentation/perf-stat.txt | 40 ++++++++++++++++++++++++++
> 1 file changed, 40 insertions(+)
>
> diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
> index 3fb5028aef08..19ed53e08294 100644
> --- a/tools/perf/Documentation/perf-stat.txt
> +++ b/tools/perf/Documentation/perf-stat.txt
> @@ -164,6 +164,46 @@ with it. --append may be used here. Examples:
> 3>results perf stat --log-fd 3 -- $cmd
> 3>>results perf stat --log-fd 3 --append -- $cmd
>
> +--ctl-fd::
> +--ctl-fd-ack::
> +
> +Listen on ctl-fd descriptor for command to control measurement ('e': enable events,
> +'d': disable events). Optionally send control command completion ('a') to fd-ack
> +descriptor to synchronize with the controlling process. Example of bash shell script
> +to enable and disable events during measurements:
> +
> +#!/bin/bash
> +
> +ctl_dir=/tmp/
> +
> +ctl_fifo=${ctl_dir}perf_ctl.fifo
> +test -p ${ctl_fifo} && unlink ${ctl_fifo}
> +mkfifo ${ctl_fifo}
> +exec {ctl_fd}<>${ctl_fifo}
> +
> +ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
> +test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
> +mkfifo ${ctl_ack_fifo}
> +exec {ctl_fd_ack}<>${ctl_ack_fifo}
> +
> +perf stat -D -1 -e cpu-cycles -a -I 1000 \
> + --ctl-fd ${ctl_fd} --ctl-fd-ack ${ctl_fd_ack} \
> + -- sleep 30 &
> +perf_pid=$!
> +
> +sleep 5 && echo 'e' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"
> +sleep 10 && echo 'd' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"
> +
> +exec {ctl_fd_ack}>&-
> +unlink ${ctl_ack_fifo}
> +
> +exec {ctl_fd}>&-
> +unlink ${ctl_fifo}
> +
> +wait -n ${perf_pid}
> +exit $?
> +
> +
> --pre::
> --post::
> Pre and post measurement hooks, e.g.:
> --
> 2.24.1
>
>
--
- Arnaldo
Em Wed, May 06, 2020 at 09:29:05PM +0300, Alexey Budankov escreveu:
>
> Implement handling of 'enable' and 'disable' control commands
> coming from control file descriptor.
>
> Signed-off-by: Alexey Budankov <[email protected]>
> ---
> tools/perf/builtin-record.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 8a14e68b86ad..2278a3efc747 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1496,6 +1496,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
> bool disabled = false, draining = false;
> int fd;
> float ratio = 0;
> + enum evlist_ctl_cmd cmd = CTL_CMD_UNSUPPORTED;
>
> atexit(record__sig_exit);
> signal(SIGCHLD, sig_handler);
> @@ -1793,8 +1794,23 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
> * Propagate error, only if there's any. Ignore positive
> * number of returned events and interrupt error.
> */
> - if (err > 0 || (err < 0 && errno == EINTR))
> + if (err > 0 || (err < 0 && errno == EINTR)) {
> err = 0;
> + if (perf_evlist__ctlfd_process(rec->evlist, &cmd) > 0) {
> + switch (cmd) {
> + case CTL_CMD_ENABLE:
> + pr_info(PERF_EVLIST__ENABLED_MSG);
> + break;
> + case CTL_CMD_DISABLE:
> + pr_info(PERF_EVLIST__DISABLED_MSG);
> + break;
> + case CTL_CMD_ACK:
> + case CTL_CMD_UNSUPPORTED:
Shouldn't we have a pr_debug() or even pr_err() for the unsupported one?
> + default:
> + break;
> + }
> + }
> + }
> waking++;
>
> if (evlist__filter_pollfd(rec->evlist, POLLERR | POLLHUP) == 0)
> --
> 2.24.1
>
>
--
- Arnaldo
Em Wed, May 06, 2020 at 09:19:22PM +0300, Alexey Budankov escreveu:
>
> Implement functions of initialization, finalization and processing
> of control commands coming from control file descriptors.
>
> Signed-off-by: Alexey Budankov <[email protected]>
> ---
> tools/perf/util/evlist.c | 100 +++++++++++++++++++++++++++++++++++++++
> tools/perf/util/evlist.h | 12 +++++
> 2 files changed, 112 insertions(+)
>
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 2db4bedc4f81..e086c846ef3a 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -1707,3 +1707,103 @@ struct evsel *perf_evlist__reset_weak_group(struct evlist *evsel_list,
> }
> return leader;
> }
> +
> +int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack)
> +{
> + if (ctl_fd == -1) {
> + pr_debug("Control descriptor is not initialized\n");
> + return 0;
> + }
> +
> + evlist->ctl_fd_pos = perf_evlist__add_pollfd(&evlist->core, ctl_fd, NULL, POLLIN);
> + if (evlist->ctl_fd_pos < 0) {
> + evlist->ctl_fd_pos = -1;
> + pr_err("Failed to add ctl fd entry: %m\n");
> + return -1;
> + }
> +
> + evlist->ctl_fd = ctl_fd;
> + evlist->ctl_fd_ack = ctl_fd_ack;
> +
> + return 0;
> +}
> +
> +int perf_evlist__finalize_ctlfd(struct evlist *evlist)
> +{
> + if (evlist->ctl_fd_pos == -1)
> + return 0;
> +
> + evlist->core.pollfd.entries[evlist->ctl_fd_pos].fd = -1;
> + evlist->ctl_fd_pos = -1;
> + evlist->ctl_fd_ack = -1;
> + evlist->ctl_fd = -1;
> +
> + return 0;
> +}
> +
> +static int perf_evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
> +{
> + int err;
> + char buf[2];
> +
> + err = read(evlist->ctl_fd, &buf, sizeof(buf));
> + if (err > 0)
> + *cmd = buf[0];
> + else if (err == -1)
> + pr_err("Failed to read from ctlfd %d: %m\n", evlist->ctl_fd);
> +
> + return err;
> +}
> +
> +static int perf_evlist__ctlfd_ack(struct evlist *evlist)
> +{
> + int err;
> + char buf[2] = {CTL_CMD_ACK, '\n'};
> +
> + if (evlist->ctl_fd_ack == -1)
> + return 0;
> +
> + err = write(evlist->ctl_fd_ack, buf, sizeof(buf));
> + if (err == -1)
> + pr_err("failed to write to ctl_ack_fd %d: %m\n", evlist->ctl_fd_ack);
> +
> + return err;
> +}
> +
> +int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
> +{
> + int err = 0;
> + int ctlfd_pos = evlist->ctl_fd_pos;
> + struct pollfd *entries = evlist->core.pollfd.entries;
> +
> + if (!entries[ctlfd_pos].revents)
> + return 0;
> +
> + if (entries[ctlfd_pos].revents & POLLIN) {
> + err = perf_evlist__ctlfd_recv(evlist, cmd);
> + if (err > 0) {
> + switch (*cmd) {
> + case CTL_CMD_ENABLE:
> + evlist__enable(evlist);
> + break;
> + case CTL_CMD_DISABLE:
> + evlist__disable(evlist);
> + break;
> + case CTL_CMD_ACK:
> + case CTL_CMD_UNSUPPORTED:
> + default:
> + pr_debug("ctlfd: unsupported %d\n", *cmd);
> + break;
> + }
> + if (!(*cmd == CTL_CMD_ACK || *cmd == CTL_CMD_UNSUPPORTED))
> + perf_evlist__ctlfd_ack(evlist);
> + }
> + }
> +
> + if (entries[ctlfd_pos].revents & (POLLHUP | POLLERR))
> + perf_evlist__finalize_ctlfd(evlist);
> + else
> + entries[ctlfd_pos].revents = 0;
> +
> + return err;
> +}
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index 62f259d89b41..84386850c290 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -358,4 +358,16 @@ void perf_evlist__force_leader(struct evlist *evlist);
> struct evsel *perf_evlist__reset_weak_group(struct evlist *evlist,
> struct evsel *evsel,
> bool close);
> +
> +enum evlist_ctl_cmd {
> + CTL_CMD_UNSUPPORTED = 0,
> + CTL_CMD_ENABLE = 'e',
> + CTL_CMD_DISABLE = 'd',
> + CTL_CMD_ACK = 'a'
> +};
Can we make this a string, I think we'll eventually ask for lots more
stuff, like asking for a --switch-output snapshot with --overwrite,
reconfiguring events to increase/decrease frequency, etc, interfacing
with PERF_EVENT_IOC_MODIFY_ATTRIBUTES, PERF_EVENT_IOC_SET_FILTER, etc.
This will also allow us to have parameters, etc, wdyt?
Also please since these are events that deal with 'struct evlist', name
them with the evlist__ prefix, not the perf_evlist__ one, as those
should be used with 'struct perf_evlist', i.e. the one in libperf
(tools/lib/perf/).
Right now this is inconsistent, we did it that way to minimize
disruption of the codebase when moving things from tools/perf/ to
tools/lib/perf/, but this confuses things and I just did a
s/perf_evsel__/evsel__) for things dealing with 'struct evsel', so lets
not add new ones with the wrong prefix, eventually we'll have perf_ only
for things in libperf.
> +
> +int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
> +int perf_evlist__finalize_ctlfd(struct evlist *evlist);
> +int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
> +
> #endif /* __PERF_EVLIST_H */
> --
> 2.24.1
>
>
--
- Arnaldo
Em Wed, May 06, 2020 at 09:30:50PM +0300, Alexey Budankov escreveu:
>
> Extend perf-record.txt file with --ctl-fd[-ack] options description.
> Document possible usage model introduced by --ctl-fd[-ack] options
> by providing example bash shell script.
Ditto, combine this patch with the one that introduces these options.
> Signed-off-by: Alexey Budankov <[email protected]>
> ---
> tools/perf/Documentation/perf-record.txt | 39 ++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> index 561ef55743e2..eabb00ed2f5d 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -613,6 +613,45 @@ appended unit character - B/K/M/G
> The number of threads to run when synthesizing events for existing processes.
> By default, the number of threads equals 1.
>
> +--ctl-fd::
> +--ctl-fd-ack::
> +Listen on ctl-fd descriptor for command to control measurement ('e': enable events,
> +'d': disable events. Optionally send control command completion ('a') to fd-ack
> +descriptor to synchronize with the controlling process. Example of bash shell script
> +to enable and disable events during measurements:
> +
> +#!/bin/bash
> +
> +ctl_dir=/tmp/
> +
> +ctl_fifo=${ctl_dir}perf_ctl.fifo
> +test -p ${ctl_fifo} && unlink ${ctl_fifo}
> +mkfifo ${ctl_fifo}
> +exec {ctl_fd}<>${ctl_fifo}
> +
> +ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
> +test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
> +mkfifo ${ctl_ack_fifo}
> +exec {ctl_fd_ack}<>${ctl_ack_fifo}
> +
> +perf record -D -1 -e cpu-cycles -a \
> + --ctl-fd ${ctl_fd} --ctl-fd-ack ${ctl_fd_ack} \
> + -- sleep 30 &
> +perf_pid=$!
> +
> +sleep 5 && echo 'e' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "resumed(${e1})"
> +sleep 10 && echo 'd' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "paused(${d1})"
> +
> +exec {ctl_fd_ack}>&-
> +unlink ${ctl_ack_fifo}
> +
> +exec {ctl_fd}>&-
> +unlink ${ctl_fifo}
> +
> +wait -n ${perf_pid}
> +exit $?
> +
> +
> SEE ALSO
> --------
> linkperf:perf-stat[1], linkperf:perf-list[1], linkperf:perf-intel-pt[1]
> --
> 2.24.1
>
>
--
- Arnaldo
Em Wed, May 06, 2020 at 09:20:54PM +0300, Alexey Budankov escreveu:
>
> Extend -D,--delay option with -1 value to start monitoring with
> events disabled to be enabled later by enable command provided
> via control file descriptor.
> Signed-off-by: Alexey Budankov <[email protected]>
> ---
> tools/perf/builtin-stat.c | 18 ++++++++++++++----
> tools/perf/util/evlist.h | 3 +++
> tools/perf/util/stat.h | 2 +-
You forgot to update tools/perf/Documentation/perf-stat.h
> 3 files changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 9775b0905146..bda777ca0420 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -383,16 +383,26 @@ static bool print_interval_and_stop(struct perf_stat_config *config, int *times)
>
> static void enable_counters(void)
> {
> - if (stat_config.initial_delay)
> + if (stat_config.initial_delay < 0) {
> + pr_info(PERF_EVLIST__DISABLED_MSG);
> + return;
> + }
> +
> + if (stat_config.initial_delay > 0) {
> + pr_info(PERF_EVLIST__DISABLED_MSG);
> usleep(stat_config.initial_delay * USEC_PER_MSEC);
> + }
>
> /*
> * We need to enable counters only if:
> * - we don't have tracee (attaching to task or cpu)
> * - we have initial delay configured
> */
> - if (!target__none(&target) || stat_config.initial_delay)
> + if (!target__none(&target) || stat_config.initial_delay) {
> evlist__enable(evsel_list);
> + if (stat_config.initial_delay > 0)
> + pr_info(PERF_EVLIST__ENABLED_MSG);
> + }
> }
>
> static void disable_counters(void)
> @@ -929,8 +939,8 @@ static struct option stat_options[] = {
> "aggregate counts per thread", AGGR_THREAD),
> OPT_SET_UINT(0, "per-node", &stat_config.aggr_mode,
> "aggregate counts per numa node", AGGR_NODE),
> - OPT_UINTEGER('D', "delay", &stat_config.initial_delay,
> - "ms to wait before starting measurement after program start"),
> + OPT_INTEGER('D', "delay", &stat_config.initial_delay,
> + "ms to wait before starting measurement after program start (-1: start with events disabled"),
> OPT_CALLBACK_NOOPT(0, "metric-only", &stat_config.metric_only, NULL,
> "Only print computed metrics. No raw values", enable_metric_only),
> OPT_BOOLEAN(0, "topdown", &topdown_run,
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index 84386850c290..874ecf068ac9 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -366,6 +366,9 @@ enum evlist_ctl_cmd {
> CTL_CMD_ACK = 'a'
> };
>
> +#define PERF_EVLIST__ENABLED_MSG "Events enabled\n"
> +#define PERF_EVLIST__DISABLED_MSG "Events disabled\n"
> +
> int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
> int perf_evlist__finalize_ctlfd(struct evlist *evlist);
> int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> index b4fdfaa7f2c0..027b9dcd902f 100644
> --- a/tools/perf/util/stat.h
> +++ b/tools/perf/util/stat.h
> @@ -113,7 +113,7 @@ struct perf_stat_config {
> FILE *output;
> unsigned int interval;
> unsigned int timeout;
> - unsigned int initial_delay;
> + int initial_delay;
> unsigned int unit_width;
> unsigned int metric_only_len;
> int times;
> --
> 2.24.1
>
>
--
- Arnaldo
On 06.05.2020 23:12, Arnaldo Carvalho de Melo wrote:
> Em Wed, May 06, 2020 at 09:20:54PM +0300, Alexey Budankov escreveu:
>>
>> Extend -D,--delay option with -1 value to start monitoring with
>> events disabled to be enabled later by enable command provided
>> via control file descriptor.
>
>> Signed-off-by: Alexey Budankov <[email protected]>
>> ---
>> tools/perf/builtin-stat.c | 18 ++++++++++++++----
>> tools/perf/util/evlist.h | 3 +++
>> tools/perf/util/stat.h | 2 +-
>
> You forgot to update tools/perf/Documentation/perf-stat.h
Good catch. Addressed in v3. Thanks!
~Alexey
On 06.05.2020 23:21, Arnaldo Carvalho de Melo wrote:
> Em Wed, May 06, 2020 at 09:19:22PM +0300, Alexey Budankov escreveu:
>>
>> Implement functions of initialization, finalization and processing
>> of control commands coming from control file descriptors.
>>
>> Signed-off-by: Alexey Budankov <[email protected]>
>> ---
>> tools/perf/util/evlist.c | 100 +++++++++++++++++++++++++++++++++++++++
>> tools/perf/util/evlist.h | 12 +++++
>> 2 files changed, 112 insertions(+)
<SNIP>
>> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
>> index 62f259d89b41..84386850c290 100644
>> --- a/tools/perf/util/evlist.h
>> +++ b/tools/perf/util/evlist.h
>> @@ -358,4 +358,16 @@ void perf_evlist__force_leader(struct evlist *evlist);
>> struct evsel *perf_evlist__reset_weak_group(struct evlist *evlist,
>> struct evsel *evsel,
>> bool close);
>> +
>> +enum evlist_ctl_cmd {
>> + CTL_CMD_UNSUPPORTED = 0,
>> + CTL_CMD_ENABLE = 'e',
>> + CTL_CMD_DISABLE = 'd',
>> + CTL_CMD_ACK = 'a'
>> +};
>
> Can we make this a string, I think we'll eventually ask for lots more
Like this?
#define EVLIST__CTL_CMD_ENABLE "enable"
#define EVLIST__CTL_CMD_DISABLE "disable"
#define EVLIST__CTL_CMD_ACK "ack"
> stuff, like asking for a --switch-output snapshot with --overwrite,
> reconfiguring events to increase/decrease frequency, etc, interfacing
> with PERF_EVENT_IOC_MODIFY_ATTRIBUTES, PERF_EVENT_IOC_SET_FILTER, etc.
>
> This will also allow us to have parameters, etc, wdyt?
Being a part of this patch the extension will implement configurability
that potentially could never be used.
Switch from int to string commands of variable length belongs to
the patches also implementing usage of that string commands.
>
> Also please since these are events that deal with 'struct evlist', name
> them with the evlist__ prefix, not the perf_evlist__ one, as those
> should be used with 'struct perf_evlist', i.e. the one in libperf
> (tools/lib/perf/).
Accepted in v3.
>
> Right now this is inconsistent, we did it that way to minimize
> disruption of the codebase when moving things from tools/perf/ to
> tools/lib/perf/, but this confuses things and I just did a
> s/perf_evsel__/evsel__) for things dealing with 'struct evsel', so lets
> not add new ones with the wrong prefix, eventually we'll have perf_ only
> for things in libperf.
>
>> +
>> +int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
>> +int perf_evlist__finalize_ctlfd(struct evlist *evlist);
>> +int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
>> +
>> #endif /* __PERF_EVLIST_H */
>> --
>> 2.24.1
>>
>>
>
On 06.05.2020 23:22, Arnaldo Carvalho de Melo wrote:
> Em Wed, May 06, 2020 at 09:22:55PM +0300, Alexey Budankov escreveu:
>>
>> Extend perf-stat.txt file with --ctl-fd[-ack] options description.
>> Document possible usage model introduced by --ctl-fd[-ack] options
>> by providing example bash shell script.
>
> Please update the docs in the same patch that introduces the options
> being documented.
Addressed in v3.
~Alexey
On 06.05.2020 23:27, Arnaldo Carvalho de Melo wrote:
> Em Wed, May 06, 2020 at 09:30:50PM +0300, Alexey Budankov escreveu:
>>
>> Extend perf-record.txt file with --ctl-fd[-ack] options description.
>> Document possible usage model introduced by --ctl-fd[-ack] options
>> by providing example bash shell script.
>
> Ditto, combine this patch with the one that introduces these options.
Addressed in v3.
~Alexey
On 06.05.2020 23:23, Arnaldo Carvalho de Melo wrote:
> Em Wed, May 06, 2020 at 09:29:05PM +0300, Alexey Budankov escreveu:
>>
>> Implement handling of 'enable' and 'disable' control commands
>> coming from control file descriptor.
>>
>> Signed-off-by: Alexey Budankov <[email protected]>
>> ---
>> tools/perf/builtin-record.c | 18 +++++++++++++++++-
>> 1 file changed, 17 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index 8a14e68b86ad..2278a3efc747 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -1496,6 +1496,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>> bool disabled = false, draining = false;
>> int fd;
>> float ratio = 0;
>> + enum evlist_ctl_cmd cmd = CTL_CMD_UNSUPPORTED;
>>
>> atexit(record__sig_exit);
>> signal(SIGCHLD, sig_handler);
>> @@ -1793,8 +1794,23 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>> * Propagate error, only if there's any. Ignore positive
>> * number of returned events and interrupt error.
>> */
>> - if (err > 0 || (err < 0 && errno == EINTR))
>> + if (err > 0 || (err < 0 && errno == EINTR)) {
>> err = 0;
>> + if (perf_evlist__ctlfd_process(rec->evlist, &cmd) > 0) {
>> + switch (cmd) {
>> + case CTL_CMD_ENABLE:
>> + pr_info(PERF_EVLIST__ENABLED_MSG);
>> + break;
>> + case CTL_CMD_DISABLE:
>> + pr_info(PERF_EVLIST__DISABLED_MSG);
>> + break;
>> + case CTL_CMD_ACK:
>> + case CTL_CMD_UNSUPPORTED:
>
> Shouldn't we have a pr_debug() or even pr_err() for the unsupported one?
It already exists on lower level, at perf_evlist__ctlfd_process() (see patch 02/11).
~Alexey
Em Thu, May 07, 2020 at 11:32:53AM +0300, Alexey Budankov escreveu:
>
> On 06.05.2020 23:21, Arnaldo Carvalho de Melo wrote:
> > Em Wed, May 06, 2020 at 09:19:22PM +0300, Alexey Budankov escreveu:
> >>
> >> Implement functions of initialization, finalization and processing
> >> of control commands coming from control file descriptors.
> >>
> >> Signed-off-by: Alexey Budankov <[email protected]>
> >> ---
> >> tools/perf/util/evlist.c | 100 +++++++++++++++++++++++++++++++++++++++
> >> tools/perf/util/evlist.h | 12 +++++
> >> 2 files changed, 112 insertions(+)
>
> <SNIP>
>
> >> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> >> index 62f259d89b41..84386850c290 100644
> >> --- a/tools/perf/util/evlist.h
> >> +++ b/tools/perf/util/evlist.h
> >> @@ -358,4 +358,16 @@ void perf_evlist__force_leader(struct evlist *evlist);
> >> struct evsel *perf_evlist__reset_weak_group(struct evlist *evlist,
> >> struct evsel *evsel,
> >> bool close);
> >> +
> >> +enum evlist_ctl_cmd {
> >> + CTL_CMD_UNSUPPORTED = 0,
> >> + CTL_CMD_ENABLE = 'e',
> >> + CTL_CMD_DISABLE = 'd',
> >> + CTL_CMD_ACK = 'a'
> >> +};
> >
> > Can we make this a string, I think we'll eventually ask for lots more
>
> Like this?
>
> #define EVLIST__CTL_CMD_ENABLE "enable"
> #define EVLIST__CTL_CMD_DISABLE "disable"
> #define EVLIST__CTL_CMD_ACK "ack"
Yeah
> > stuff, like asking for a --switch-output snapshot with --overwrite,
> > reconfiguring events to increase/decrease frequency, etc, interfacing
> > with PERF_EVENT_IOC_MODIFY_ATTRIBUTES, PERF_EVENT_IOC_SET_FILTER, etc.
> >
> > This will also allow us to have parameters, etc, wdyt?
>
> Being a part of this patch the extension will implement configurability
> that potentially could never be used.
>
> Switch from int to string commands of variable length belongs to
> the patches also implementing usage of that string commands.
Well, at that point we would have to support both, i.e. the way you're
doing now with integers, and as strings, otherwise 3rd party tooling
(vtune? :)) using this interface would break.
I.e. this is like the syscall interface.
So if we have "enable" now we can go ahead and forever understand that
as "please enable this evlist", but in the future we can extend it and
pass parameters to it, to control how that enablement will take place,
perhaps with a delay, etc.
> > Also please since these are events that deal with 'struct evlist', name
> > them with the evlist__ prefix, not the perf_evlist__ one, as those
> > should be used with 'struct perf_evlist', i.e. the one in libperf
> > (tools/lib/perf/).
>
> Accepted in v3.
>
> >
> > Right now this is inconsistent, we did it that way to minimize
> > disruption of the codebase when moving things from tools/perf/ to
> > tools/lib/perf/, but this confuses things and I just did a
> > s/perf_evsel__/evsel__) for things dealing with 'struct evsel', so lets
> > not add new ones with the wrong prefix, eventually we'll have perf_ only
> > for things in libperf.
> >
> >> +
> >> +int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
> >> +int perf_evlist__finalize_ctlfd(struct evlist *evlist);
> >> +int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
> >> +
> >> #endif /* __PERF_EVLIST_H */
> >> --
> >> 2.24.1
> >>
> >>
> >
--
- Arnaldo
Em Thu, May 07, 2020 at 11:58:45AM +0300, Alexey Budankov escreveu:
>
> On 06.05.2020 23:23, Arnaldo Carvalho de Melo wrote:
> > Em Wed, May 06, 2020 at 09:29:05PM +0300, Alexey Budankov escreveu:
> >>
> >> Implement handling of 'enable' and 'disable' control commands
> >> coming from control file descriptor.
> >>
> >> Signed-off-by: Alexey Budankov <[email protected]>
> >> ---
> >> tools/perf/builtin-record.c | 18 +++++++++++++++++-
> >> 1 file changed, 17 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> >> index 8a14e68b86ad..2278a3efc747 100644
> >> --- a/tools/perf/builtin-record.c
> >> +++ b/tools/perf/builtin-record.c
> >> @@ -1496,6 +1496,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
> >> bool disabled = false, draining = false;
> >> int fd;
> >> float ratio = 0;
> >> + enum evlist_ctl_cmd cmd = CTL_CMD_UNSUPPORTED;
> >>
> >> atexit(record__sig_exit);
> >> signal(SIGCHLD, sig_handler);
> >> @@ -1793,8 +1794,23 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
> >> * Propagate error, only if there's any. Ignore positive
> >> * number of returned events and interrupt error.
> >> */
> >> - if (err > 0 || (err < 0 && errno == EINTR))
> >> + if (err > 0 || (err < 0 && errno == EINTR)) {
> >> err = 0;
> >> + if (perf_evlist__ctlfd_process(rec->evlist, &cmd) > 0) {
> >> + switch (cmd) {
> >> + case CTL_CMD_ENABLE:
> >> + pr_info(PERF_EVLIST__ENABLED_MSG);
> >> + break;
> >> + case CTL_CMD_DISABLE:
> >> + pr_info(PERF_EVLIST__DISABLED_MSG);
> >> + break;
> >> + case CTL_CMD_ACK:
> >> + case CTL_CMD_UNSUPPORTED:
> >
> > Shouldn't we have a pr_debug() or even pr_err() for the unsupported one?
>
> It already exists on lower level, at perf_evlist__ctlfd_process() (see patch 02/11).
oic
> ~Alexey
--
- Arnaldo
On 07.05.2020 20:01, Arnaldo Carvalho de Melo wrote:
> Em Thu, May 07, 2020 at 11:32:53AM +0300, Alexey Budankov escreveu:
>>
>> On 06.05.2020 23:21, Arnaldo Carvalho de Melo wrote:
>>> Em Wed, May 06, 2020 at 09:19:22PM +0300, Alexey Budankov escreveu:
>>>>
>>>> Implement functions of initialization, finalization and processing
>>>> of control commands coming from control file descriptors.
>>>>
>>>> Signed-off-by: Alexey Budankov <[email protected]>
>>>> ---
>>>> tools/perf/util/evlist.c | 100 +++++++++++++++++++++++++++++++++++++++
>>>> tools/perf/util/evlist.h | 12 +++++
>>>> 2 files changed, 112 insertions(+)
>>
>> <SNIP>
>>
>>>> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
>>>> index 62f259d89b41..84386850c290 100644
>>>> --- a/tools/perf/util/evlist.h
>>>> +++ b/tools/perf/util/evlist.h
>>>> @@ -358,4 +358,16 @@ void perf_evlist__force_leader(struct evlist *evlist);
>>>> struct evsel *perf_evlist__reset_weak_group(struct evlist *evlist,
>>>> struct evsel *evsel,
>>>> bool close);
>>>> +
>>>> +enum evlist_ctl_cmd {
>>>> + CTL_CMD_UNSUPPORTED = 0,
>>>> + CTL_CMD_ENABLE = 'e',
>>>> + CTL_CMD_DISABLE = 'd',
>>>> + CTL_CMD_ACK = 'a'
>>>> +};
>>>
>>> Can we make this a string, I think we'll eventually ask for lots more
>>
>> Like this?
>>
>> #define EVLIST__CTL_CMD_ENABLE "enable"
>> #define EVLIST__CTL_CMD_DISABLE "disable"
>> #define EVLIST__CTL_CMD_ACK "ack"
>
> Yeah
Well, ok. Accepted in v3.
Command becomes of variable length of chars + \n,
in comparison to current single char + \n.
>
>>> stuff, like asking for a --switch-output snapshot with --overwrite,
>>> reconfiguring events to increase/decrease frequency, etc, interfacing
>>> with PERF_EVENT_IOC_MODIFY_ATTRIBUTES, PERF_EVENT_IOC_SET_FILTER, etc.
>>>
>>> This will also allow us to have parameters, etc, wdyt?
>>
>> Being a part of this patch the extension will implement configurability
>> that potentially could never be used.
>>
>> Switch from int to string commands of variable length belongs to
>> the patches also implementing usage of that string commands.
>
> Well, at that point we would have to support both, i.e. the way you're
> doing now with integers, and as strings, otherwise 3rd party tooling
> (vtune? :)) using this interface would break.
>
> I.e. this is like the syscall interface.
>
> So if we have "enable" now we can go ahead and forever understand that
> as "please enable this evlist", but in the future we can extend it and
> pass parameters to it, to control how that enablement will take place,
> perhaps with a delay, etc.
>
>>> Also please since these are events that deal with 'struct evlist', name
>>> them with the evlist__ prefix, not the perf_evlist__ one, as those
>>> should be used with 'struct perf_evlist', i.e. the one in libperf
>>> (tools/lib/perf/).
>>
>> Accepted in v3.
>>
>>>
>>> Right now this is inconsistent, we did it that way to minimize
>>> disruption of the codebase when moving things from tools/perf/ to
>>> tools/lib/perf/, but this confuses things and I just did a
>>> s/perf_evsel__/evsel__) for things dealing with 'struct evsel', so lets
>>> not add new ones with the wrong prefix, eventually we'll have perf_ only
>>> for things in libperf.
>>>
>>>> +
>>>> +int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
>>>> +int perf_evlist__finalize_ctlfd(struct evlist *evlist);
>>>> +int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
>>>> +
>>>> #endif /* __PERF_EVLIST_H */
>>>> --
>>>> 2.24.1
>>>>
>>>>
>>>
>