This patchset helps in listing dtrace style markers(SDT) present in user space
applications through perf.
Notes/markers are placed at important places by the
developers. They have a negligible overhead when not enabled.
We can enable them and probe at these places and find some important information
like the arguments' values, etc.
We have lots of applications which use SDT markers today, like:
Postgresql, MySql, Mozilla, Perl, Python, Java, Ruby, libvirt, QEMU, glib
To add SDT markers into user applications:
We need to have this header sys/sdt.h present.
sys/sdt.h used is version 3.
If not present, install systemtap-sdt-devel package (for fedora-20).
With this patchset,
- Use perf sdt-cache --add to add SDT events to a cache.
# perf sdt-cache --add ./user_app
4 SDT events added for /home/user/user_app!
- Use perf sdt-cache --del to remove SDT events from the cache>
# perf sdt-cache --del ./user_app
4 events removed for /home/user/user_app!
- Dump the cache onto stdout using perf sdt-cache --dump:
# perf sdt-cache --dump
/home/user/user_app :
%user_app:foo_start
%user_app:fun_start
- To probe and trace an SDT event :
# perf record -e %user_app:foo_start -aR sleep 10
The support for perf to sdt events has undergone a lot of changes since it was
introduced. After a lot of discussions (https://lkml.org/lkml/2014/7/20/284), the
patchset is subdivided for ease of review.
Previously, a patchset supporting "perf list sdt" was posted, but it didn't make
much sense since, only listing SDT events for an ELF won't help.
This patchset aims at adding a sub-command "sdt-cache" to perf to manage a cache
for management of the SDT events.
This link shows an example of marker probing with Systemtap:
https://sourceware.org/systemtap/wiki/AddingUserSpaceProbingToApps
This link provides important info regarding SDT notes:
http://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
- Markers in binaries :
These SDT markers are present in the ELF in the section named
".note.stapsdt".
Here, the name of the marker, its provider, type, location, base
address, semaphore address.
We can retrieve these values using the members name_off and desc_off in
Nhdr structure. If these are not enabled, they are present in the ELF as nop.
Changes since last series :
- Changed the entire (linked) list structure to hash lists to manage the SDT events.
- Added a sub command "sdt-cache" to perf to manage SDT events in the system.
- Added support to add and remove SDT events onto a cache.
- Added support to "perf record" to probe and record the SDT events.
TODO:
- Add support to add most of the SDT events on a system to the cache.
- Recognizing arguments and support to probe on them.
---
Hemant Kumar (5):
perf/sdt: ELF support for SDT
perf/sdt: Add SDT events into a cache
perf/sdt: Show SDT cache contents
perf/sdt: Delete SDT events from cache
perf/sdt: Add support to perf record to trace SDT events
tools/perf/Makefile.perf | 3
tools/perf/builtin-record.c | 21 +
tools/perf/builtin-sdt-cache.c | 108 +++++
tools/perf/builtin.h | 1
tools/perf/perf.c | 1
tools/perf/util/parse-events.c | 7
tools/perf/util/parse-events.h | 7
tools/perf/util/probe-event.c | 120 ++++-
tools/perf/util/probe-event.h | 8
tools/perf/util/probe-finder.c | 3
tools/perf/util/sdt.c | 925 ++++++++++++++++++++++++++++++++++++++++
tools/perf/util/sdt.h | 30 +
tools/perf/util/symbol-elf.c | 207 +++++++++
tools/perf/util/symbol.h | 21 +
14 files changed, 1440 insertions(+), 22 deletions(-)
create mode 100644 tools/perf/builtin-sdt-cache.c
create mode 100644 tools/perf/util/sdt.c
create mode 100644 tools/perf/util/sdt.h
--
Signature
This patch serves as the initial support to identify and list SDT events in binaries.
When programs containing SDT markers are compiled, gcc with the help of assembler
directives identifies them and places them in the section ".note.stapsdt". To find
these markers from the binaries, one needs to traverse through this section and
parse the relevant details like the name, type and location of the marker. Also,
the original location could be skewed due to the effect of prelinking. If that is
the case, the locations need to be adjusted.
The functions in this patch open a given ELF, find out the SDT section, parse the
relevant details, adjust the location (if necessary) and populate them in a list.
Some improvements have been made in this patch as suggested by Namhyung Kim.
Signed-off-by: Hemant Kumar <[email protected]>
---
tools/perf/util/symbol-elf.c | 207 ++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/symbol.h | 19 ++++
2 files changed, 226 insertions(+)
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 6864661..60d1805 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1619,6 +1619,213 @@ void kcore_extract__delete(struct kcore_extract *kce)
unlink(kce->extract_filename);
}
+/*
+ * populate_sdt_note() : Responsible for parsing the section .note.stapsdt and
+ * after adjusting the note's location, returns that to the calling functions.
+ */
+static int populate_sdt_note(Elf **elf, const char *data, size_t len, int type,
+ struct sdt_note **note)
+{
+ const char *provider, *name;
+ struct sdt_note *tmp = NULL;
+ GElf_Ehdr ehdr;
+ GElf_Addr base_off = 0;
+ GElf_Shdr shdr;
+ int ret = -1;
+ int i;
+
+ union {
+ Elf64_Addr a64[3];
+ Elf32_Addr a32[3];
+ } buf;
+
+ Elf_Data dst = {
+ .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
+ .d_size = gelf_fsize((*elf), ELF_T_ADDR, 3, EV_CURRENT),
+ .d_off = 0, .d_align = 0
+ };
+ Elf_Data src = {
+ .d_buf = (void *) data, .d_type = ELF_T_ADDR,
+ .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
+ .d_align = 0
+ };
+
+ /* Check the type of each of the notes */
+ if (type != SDT_NOTE_TYPE)
+ goto out_err;
+
+ tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
+ if (!tmp) {
+ ret = -ENOMEM;
+ goto out_err;
+ }
+
+ INIT_LIST_HEAD(&tmp->note_list);
+
+ if (len < dst.d_size + 3)
+ goto out_free_note;
+
+ /* Translation from file representation to memory representation */
+ if (gelf_xlatetom(*elf, &dst, &src,
+ elf_getident(*elf, NULL)[EI_DATA]) == NULL)
+ printf("gelf_xlatetom : %s\n", elf_errmsg(-1));
+
+ /* Populate the fields of sdt_note */
+ provider = data + dst.d_size;
+
+ name = (const char *)memchr(provider, '\0', data + len - provider);
+ if (name++ == NULL)
+ goto out_free_note;
+
+ tmp->provider = strdup(provider);
+ if (!tmp->provider) {
+ ret = -ENOMEM;
+ goto out_free_note;
+ }
+ tmp->name = strdup(name);
+ if (!tmp->name) {
+ ret = -ENOMEM;
+ goto out_free_prov;
+ }
+
+ /* Obtain the addresses */
+ if (gelf_getclass(*elf) == ELFCLASS32) {
+ for (i = 0; i < 3; i++)
+ tmp->addr.a32[i] = buf.a32[i];
+ tmp->bit32 = true;
+ } else {
+ for (i = 0; i < 3; i++)
+ tmp->addr.a64[i] = buf.a64[i];
+ tmp->bit32 = false;
+ }
+
+ /* Now Adjust the prelink effect */
+ if (!gelf_getehdr(*elf, &ehdr)) {
+ pr_debug("%s : cannot get elf header.\n", __func__);
+ ret = -EBADF;
+ goto out_free_name;
+ }
+
+ /*
+ * Find out the .stapsdt.base section.
+ * This scn will help us to handle prelinking (if present).
+ * Compare the retrieved file offset of the base section with the
+ * base address in the description of the SDT note. If its different,
+ * then accordingly, adjust the note location.
+ */
+ if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
+ base_off = shdr.sh_offset;
+ if (base_off) {
+ if (tmp->bit32)
+ tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
+ tmp->addr.a32[1];
+ else
+ tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
+ tmp->addr.a64[1];
+ }
+ }
+
+ *note = tmp;
+ return 0;
+
+out_free_name:
+ free(tmp->name);
+out_free_prov:
+ free(tmp->provider);
+out_free_note:
+ free(tmp);
+out_err:
+ return ret;
+}
+
+/*
+ * construct_sdt_notes_list() : Scans the sections in 'elf' for the section
+ * .note.stapsdt. It, then calls populate_sdt_note to find
+ * out the SDT events and populates the 'sdt_notes'.
+ */
+static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
+{
+ GElf_Ehdr ehdr;
+ Elf_Scn *scn = NULL;
+ Elf_Data *data;
+ GElf_Shdr shdr;
+ size_t shstrndx, next;
+ GElf_Nhdr nhdr;
+ size_t name_off, desc_off, offset;
+ struct sdt_note *tmp = NULL;
+ int ret = 0;
+
+ if (gelf_getehdr(elf, &ehdr) == NULL) {
+ ret = -EBADF;
+ goto out_ret;
+ }
+ if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
+ ret = -EBADF;
+ goto out_ret;
+ }
+
+ /* Look for the required section */
+ scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
+ if (!scn) {
+ ret = -ENOENT;
+ goto out_ret;
+ }
+
+ if (!(shdr.sh_type == SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
+ ret = -ENOENT;
+ goto out_ret;
+ }
+
+ data = elf_getdata(scn, NULL);
+
+ /* Get the SDT notes */
+ for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
+ &desc_off)) > 0; offset = next) {
+ if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
+ !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
+ sizeof(SDT_NOTE_NAME))) {
+ ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
+ nhdr.n_descsz, nhdr.n_type,
+ &tmp);
+ if (ret < 0)
+ goto out_ret;
+ list_add_tail(&tmp->note_list, sdt_notes);
+ }
+ }
+ if (list_empty(sdt_notes))
+ ret = -ENOENT;
+
+out_ret:
+ return ret;
+}
+
+/*
+ * get_sdt_note_list() : Takes two arguments "head" and "target", where head
+ * is the head of the SDT events' list and "target" is the file name as to
+ * where the SDT events should be looked for. This opens the file, initializes
+ * the ELF and then calls construct_sdt_notes_list.
+ */
+int get_sdt_note_list(struct list_head *head, const char *target)
+{
+ Elf *elf;
+ int fd, ret;
+
+ fd = open(target, O_RDONLY);
+ if (fd < 0)
+ return -EBADF;
+
+ elf = elf_begin(fd, ELF_C_READ, NULL);
+ if (!elf) {
+ ret = -EBADF;
+ goto out_close;
+ }
+ ret = construct_sdt_notes_list(elf, head);
+ elf_end(elf);
+out_close:
+ close(fd);
+ return ret;
+}
+
void symbol__elf_init(void)
{
elf_version(EV_CURRENT);
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 615c752..cef620e 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -294,4 +294,23 @@ int compare_proc_modules(const char *from, const char *to);
int setup_list(struct strlist **list, const char *list_str,
const char *list_name);
+/* structure containing an SDT note's info */
+struct sdt_note {
+ char *name; /* name of the note*/
+ char *provider; /* provider name */
+ bool bit32; /* whether the location is 32 bits? */
+ union { /* location, base and semaphore addrs */
+ Elf64_Addr a64[3];
+ Elf32_Addr a32[3];
+ } addr;
+ struct list_head note_list; /* SDT notes' list */
+};
+
+int get_sdt_note_list(struct list_head *head, const char *target);
+
+#define SDT_BASE_SCN ".stapsdt.base"
+#define SDT_NOTE_SCN ".note.stapsdt"
+#define SDT_NOTE_TYPE 3
+#define SDT_NOTE_NAME "stapsdt"
+
#endif /* __PERF_SYMBOL */
This patch adds a new sub-command to perf : sdt-cache.
sdt-cache command can be used to add, remove and dump SDT events.
This patch adds support to only "add" the SDT events. The rest of the
patches add support to rest of them.
When user invokes "perf sdt-cache add <file-name>", two hash tables are
created: file_hash list and event_hash list. A typical entry in a file_hash
table looks like:
file hash file_sdt_ent file_sdt_ent
|---------| --------------- -------------
| list ==|===|=>file_list =|===|=>file_list=|==..
key = 644 =>| | | sbuild_id | | sbuild_id |
|---------| | name | | name |
| | | sdt_list | | sdt_list |
key = 645 =>| list | | || | | || |
|---------| --------------- --------------
|| || || Connected to SDT notes
---------------
| note_list |
sdt_note| name |
| provider |
-----||--------
connected to other SDT notes
Each entry of the file_hash table is a list which connects to file_list in
file_sdt_ent. file_sdt_ent is allocated per file whenever a file is mapped
to file_hash list. File name serves as the key to this hash table.
If a file is added to this hash list, a file_sdt_ent is allocated and a
list of SDT events in that file is created and assigned to sdt_list of
file_sdt_ent.
Example usage :
# ./perf sdt-cache --add /home/user_app
4 events added for /home/user_app!
# ./perf sdt-cache --add /lib64/libc.so.6
8 events added for /usr/lib64/libc-2.16.so!
Signed-off-by: Hemant Kumar <[email protected]>
---
tools/perf/Makefile.perf | 3
tools/perf/builtin-sdt-cache.c | 58 +++
tools/perf/builtin.h | 1
tools/perf/perf.c | 1
tools/perf/util/parse-events.h | 2
tools/perf/util/probe-event.h | 1
tools/perf/util/sdt.c | 665 ++++++++++++++++++++++++++++++++++++++++
tools/perf/util/sdt.h | 30 ++
8 files changed, 761 insertions(+)
create mode 100644 tools/perf/builtin-sdt-cache.c
create mode 100644 tools/perf/util/sdt.c
create mode 100644 tools/perf/util/sdt.h
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 9670a16..87eeafd 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -272,6 +272,7 @@ LIB_H += util/run-command.h
LIB_H += util/sigchain.h
LIB_H += util/dso.h
LIB_H += util/symbol.h
+LIB_H += util/sdt.h
LIB_H += util/color.h
LIB_H += util/values.h
LIB_H += util/sort.h
@@ -335,6 +336,7 @@ LIB_OBJS += $(OUTPUT)util/sigchain.o
LIB_OBJS += $(OUTPUT)util/dso.o
LIB_OBJS += $(OUTPUT)util/symbol.o
LIB_OBJS += $(OUTPUT)util/symbol-elf.o
+LIB_OBJS += $(OUTPUT)util/sdt.o
LIB_OBJS += $(OUTPUT)util/color.o
LIB_OBJS += $(OUTPUT)util/pager.o
LIB_OBJS += $(OUTPUT)util/header.o
@@ -449,6 +451,7 @@ BUILTIN_OBJS += $(OUTPUT)builtin-timechart.o
BUILTIN_OBJS += $(OUTPUT)builtin-top.o
BUILTIN_OBJS += $(OUTPUT)builtin-script.o
BUILTIN_OBJS += $(OUTPUT)builtin-probe.o
+BUILTIN_OBJS += $(OUTPUT)builtin-sdt-cache.o
BUILTIN_OBJS += $(OUTPUT)builtin-kmem.o
BUILTIN_OBJS += $(OUTPUT)builtin-lock.o
BUILTIN_OBJS += $(OUTPUT)builtin-kvm.o
diff --git a/tools/perf/builtin-sdt-cache.c b/tools/perf/builtin-sdt-cache.c
new file mode 100644
index 0000000..3c30829
--- /dev/null
+++ b/tools/perf/builtin-sdt-cache.c
@@ -0,0 +1,58 @@
+/*
+ * builtin-sdt-cache.c
+ *
+ * Builtin sdt command: Add/remove/show SDT events
+ */
+#include "builtin.h"
+
+#include "perf.h"
+
+#include "util/parse-events.h"
+#include "util/cache.h"
+#include "util/parse-options.h"
+#include "symbol.h"
+
+/* Session management structure */
+static struct {
+ bool add;
+ const char *target;
+} params;
+
+static int opt_add_sdt_events(const struct option *opt __maybe_unused,
+ const char *str, int unset __maybe_unused)
+{
+ params.add = true;
+ params.target = str;
+
+ return 0;
+}
+
+int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused)
+{
+ int ret;
+ const struct option sdt_cache_options[] = {
+ OPT_CALLBACK('a', "add", NULL, "filename",
+ "add SDT events from a file.",
+ opt_add_sdt_events),
+ OPT_END()
+ };
+ const char * const sdt_cache_usage[] = {
+ "perf sdt_cache --add filename",
+ NULL
+ };
+
+ argc = parse_options(argc, argv, sdt_cache_options,
+ sdt_cache_usage,
+ PARSE_OPT_STOP_AT_NON_OPTION);
+
+ setup_pager();
+
+ symbol__elf_init();
+ if (params.add) {
+ ret = add_sdt_events(params.target);
+ if (ret < 0)
+ pr_err("Cannot add SDT events to cache!\n");
+ } else
+ usage_with_options(sdt_cache_usage, sdt_cache_options);
+ return 0;
+}
diff --git a/tools/perf/builtin.h b/tools/perf/builtin.h
index b210d62..2746358 100644
--- a/tools/perf/builtin.h
+++ b/tools/perf/builtin.h
@@ -37,6 +37,7 @@ extern int cmd_test(int argc, const char **argv, const char *prefix);
extern int cmd_trace(int argc, const char **argv, const char *prefix);
extern int cmd_inject(int argc, const char **argv, const char *prefix);
extern int cmd_mem(int argc, const char **argv, const char *prefix);
+extern int cmd_sdt_cache(int argc, const char **argv, const char *prefix);
extern int find_scripts(char **scripts_array, char **scripts_path_array);
#endif
diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index 95c58fc..81d652f 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -51,6 +51,7 @@ static struct cmd_struct commands[] = {
{ "sched", cmd_sched, 0 },
#ifdef HAVE_LIBELF_SUPPORT
{ "probe", cmd_probe, 0 },
+ { "sdt-cache", cmd_sdt_cache, 0 },
#endif
{ "kmem", cmd_kmem, 0 },
{ "lock", cmd_lock, 0 },
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index df094b4..e6efe2c 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -109,4 +109,6 @@ extern int is_valid_tracepoint(const char *event_string);
extern int valid_debugfs_mount(const char *debugfs);
+int add_sdt_events(const char *file);
+
#endif /* __PERF_PARSE_EVENTS_H */
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 776c934..5ba93c6 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -5,6 +5,7 @@
#include "intlist.h"
#include "strlist.h"
#include "strfilter.h"
+#include "sdt.h"
extern bool probe_event_dry_run;
diff --git a/tools/perf/util/sdt.c b/tools/perf/util/sdt.c
new file mode 100644
index 0000000..0b56210
--- /dev/null
+++ b/tools/perf/util/sdt.c
@@ -0,0 +1,665 @@
+/*
+ * util/sdt.c
+ * This contains the relevant functions needed to find the SDT events
+ * in a binary and adding them to a cache.
+ *
+ * TODOS:
+ * - Listing SDT events in most of the binaries present in the system.
+ * - Looking into directories provided by the user for binaries with SDTs,
+ * etc.
+ * - Support SDT event arguments.
+ * - Support SDT event semaphores.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <limits.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+
+#include "parse-events.h"
+#include "probe-event.h"
+#include "linux/list.h"
+#include "symbol.h"
+#include "build-id.h"
+
+struct file_info {
+ char *name; /* File name */
+ char sbuild_id[BUILD_ID_SIZE * 2 + 1]; /* Build id of the file */
+};
+
+/**
+ * get_hash_key: calculates the key to hash tables
+ * @str: input string
+ *
+ * adds the ascii values for all the chars in @str, multiplies with a prime
+ * and finds the modulo with HASH_TABLE_SIZE.
+ *
+ * Return : An integer key
+ */
+static unsigned get_hash_key(const char *str)
+{
+ unsigned value = 0, key;
+ unsigned c;
+
+ for (c = 0; str[c] != '\0'; c++)
+ value += str[c];
+
+ key = (value * 37) % HASH_TABLE_SIZE;
+
+ return key;
+}
+
+/**
+ * sdt_err: print SDT related error
+ * @val: error code
+ * @target: input file
+ *
+ * Display error corresponding to @val for file @target
+ */
+static int sdt_err(int val, const char *target)
+{
+ switch (-val) {
+ case 0:
+ break;
+ case ENOENT:
+ /* Absence of SDT markers */
+ pr_err("%s: No SDT events found\n", target);
+ break;
+ case EBADF:
+ pr_err("%s: Bad file name\n", target);
+ break;
+ default:
+ pr_err("%s\n", strerror(val));
+ }
+
+ return val;
+}
+
+/**
+ * cleanup_sdt_note_list : free the sdt notes' list
+ * @sdt_notes: sdt notes' list
+ *
+ * Free up the SDT notes in @sdt_notes.
+ */
+static void cleanup_sdt_note_list(struct list_head *sdt_notes)
+{
+ struct sdt_note *tmp, *pos;
+
+ if (list_empty(sdt_notes))
+ return;
+
+ list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
+ list_del(&pos->note_list);
+ free(pos->name);
+ free(pos->provider);
+ free(pos);
+ }
+}
+
+/**
+ * file_list_entry__init: Initialize a file_list_entry
+ * @fse: file_list_entry
+ * @file: file information
+ *
+ * Initializes @fse with the build id of a @file.
+ */
+static void file_list_entry__init(struct file_sdt_ent *fse,
+ struct file_info *file)
+{
+ strcpy(fse->sbuild_id, file->sbuild_id);
+ INIT_LIST_HEAD(&fse->file_list);
+ INIT_LIST_HEAD(&fse->sdt_list);
+}
+
+/**
+ * sdt_events__get_count: Counts the number of sdt events
+ * @start: list_head to sdt_notes list
+ *
+ * Returns the number of SDT notes in a list
+ */
+static int sdt_events__get_count(struct list_head *start)
+{
+ struct sdt_note *sdt_ptr;
+ int count = 0;
+
+ list_for_each_entry(sdt_ptr, start, note_list) {
+ count++;
+ }
+ return count;
+}
+
+/**
+ * file_hash_list__add: add an entry to file_hash_list
+ * @sdt_notes: list of sdt_notes
+ * @file: file name and build id
+ * @file_hash: hash table for file and sdt notes
+ *
+ * Get the key corresponding to @file->name. Fetch the entry
+ * for that key. Build a file_list_entry fse, assign the SDT notes
+ * to it and then assign fse to the fetched entry into the hash.
+ */
+static int file_hash_list__add(struct list_head *sdt_notes,
+ struct file_info *file,
+ struct hash_list *file_hash)
+{
+ struct file_sdt_ent *fse;
+ struct list_head *ent_head;
+ int key, nr_evs;
+
+ key = get_hash_key(file->name);
+ ent_head = &file_hash->ent[key].list;
+
+ /* Initialize the file entry */
+ fse = (struct file_sdt_ent *)malloc(sizeof(struct file_sdt_ent));
+ if (!fse)
+ return -ENOMEM;
+ file_list_entry__init(fse, file);
+ nr_evs = sdt_events__get_count(sdt_notes);
+ list_splice(sdt_notes, &fse->sdt_list);
+
+ printf("%d events added for %s\n", nr_evs, file->name);
+ strcpy(fse->name, file->name);
+
+ /* Add the file to the file hash entry */
+ list_add(&fse->file_list, ent_head);
+
+ return MOD;
+}
+
+/**
+ * file_hash_list__remove: Remove a file entry from the file_hash table
+ * @file_hash: file_hash_table
+ * @target: file name
+ *
+ * Removes the entries from file_hash table corresponding to @target.
+ * Gets the key from @target. Also frees up the SDT events for that
+ * file.
+ */
+static int file_hash_list__remove(struct hash_list *file_hash,
+ const char *target)
+{
+ struct file_sdt_ent *fse, *tmp1;
+ struct list_head *sdt_head, *ent_head;
+ struct sdt_note *sdt_ptr, *tmp2;
+
+ char *res_path;
+ int key, nr_del = 0;
+
+ key = get_hash_key(target);
+ ent_head = &file_hash->ent[key].list;
+
+ res_path = realpath(target, NULL);
+ if (!res_path)
+ return -ENOMEM;
+
+ if (list_empty(ent_head))
+ return 0;
+
+ /* Got the file hash entry */
+ list_for_each_entry_safe(fse, tmp1, ent_head, file_list) {
+ sdt_head = &fse->sdt_list;
+ if (strcmp(res_path, fse->name))
+ continue;
+
+ /* Got the file list entry, now start removing */
+ list_for_each_entry_safe(sdt_ptr, tmp2, sdt_head, note_list) {
+ list_del(&sdt_ptr->note_list);
+ free(sdt_ptr->name);
+ free(sdt_ptr->provider);
+ free(sdt_ptr);
+ nr_del++;
+ }
+ list_del(&fse->file_list);
+ list_del(&fse->sdt_list);
+ free(fse);
+ }
+
+ return nr_del;
+}
+/**
+ * file_hash_list__entry_exists: Checks if a file is already present
+ * @file_hash: file_hash table
+ * @file: file name and build id to check
+ *
+ * Obtains the key from @file->name, fetches the correct entry,
+ * and goes through the chain to find out the correct file list entry.
+ * Compares the build id, if they match, return true, else, false.
+ */
+static bool file_hash_list__entry_exists(struct hash_list *file_hash,
+ struct file_info *file)
+{
+ struct file_sdt_ent *fse;
+ struct list_head *ent_head;
+ int key;
+
+ key = get_hash_key(file->name);
+ ent_head = &file_hash->ent[key].list;
+ if (list_empty(ent_head))
+ return false;
+
+ list_for_each_entry(fse, ent_head, file_list) {
+ if (!strcmp(file->name, fse->name)) {
+ if (!strcmp(file->sbuild_id, fse->sbuild_id))
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/**
+ * copy_delim: copy till a character
+ * @src: source string
+ * @target: dest string
+ * @delim: till this character
+ * @len: length of @target
+ * @end: end of @src
+ *
+ * Returns the number of chars copied.
+ * NOTE: We need @end as @src may or may not be terminated by NULL
+ */
+static int copy_delim(char *src, char *target, char delim, size_t len,
+ char *end)
+{
+ int i;
+
+ memset(target, '\0', len);
+ for (i = 0; (src[i] != delim) && !(src + i > end) ; i++)
+ target[i] = src[i];
+
+ return i + 1;
+}
+
+/**
+ * sdt_note__read: Parse SDT note info
+ * @ptr: raw data
+ * @sdt_list: empty list
+ * @end: end of the raw data
+ *
+ * Parse @ptr to find out SDT note name, provider, location and semaphore.
+ * All these data are separated by DELIM.
+ */
+static void sdt_note__read(char **ptr, struct list_head *sdt_list, char *end)
+{
+ struct sdt_note *sn;
+ char addr[MAX_ADDR];
+ int len = 0;
+
+ while (1) {
+ sn = (struct sdt_note *)malloc(sizeof(struct sdt_note));
+ if (!sn)
+ return;
+ INIT_LIST_HEAD(&sn->note_list);
+ sn->name = (char *)malloc(PATH_MAX);
+ if (!sn->name)
+ return;
+ sn->provider = (char *)malloc(PATH_MAX);
+ if (!sn->provider)
+ return;
+ /* Extract the provider name */
+ len = copy_delim(*ptr, sn->provider, DELIM, PATH_MAX, end);
+ *ptr += len;
+
+ /* Extract the note name */
+ len = copy_delim(*ptr, sn->name, DELIM, PATH_MAX, end);
+ *ptr += len;
+
+ /* Extract the note's location */
+ len = copy_delim(*ptr, addr , DELIM, MAX_ADDR, end);
+ *ptr += len;
+ sscanf(addr, "%lx", &sn->addr.a64[0]);
+
+ /* Extract the sem location */
+ len = copy_delim(*ptr, addr , DELIM, MAX_ADDR, end);
+ *ptr += len;
+ sscanf(addr, "%lx", &sn->addr.a64[2]);
+ list_add(&sn->note_list, sdt_list);
+
+ /* If the entries for this file are finished */
+ if (**ptr == DELIM)
+ break;
+ }
+}
+
+/**
+ * file_hash_list__populate: Fill up the file hash table
+ * @file_hash: empty file hash table
+ * @data: raw cache data
+ * @size: size of data
+ *
+ * Find out the end of data with help of @size. Start parsing @data.
+ * In the outer loop, it reads the 'key' delimited by "::-". In the inner
+ * loop, it reads the file name, build id and calls sdt_note__read() to
+ * read the SDT notes. Multiple entries for the same key are delimited
+ * by "::". Then, it assigns the file name, build id and SDT notes to the
+ * list entry corresponding to 'key'.
+ */
+static void file_hash_list__populate(struct hash_list *file_hash, char *data,
+ off_t size)
+{
+ struct list_head *ent_head;
+ struct file_sdt_ent *fse;
+ char *end, tmp[PATH_MAX], *ptr;
+ int key, len = 0;
+
+ end = data + size - 1;
+ ptr = data;
+ if (ptr == end)
+ return;
+ do {
+ /* Obtain the key */
+ len = copy_delim(ptr, tmp, DELIM, PATH_MAX, end);
+ ptr += len;
+ key = atoi(tmp);
+ /* Obtain the file_hash list entry */
+ ent_head = &file_hash->ent[key].list;
+ while (1) {
+ fse = (struct file_sdt_ent *)
+ malloc(sizeof(struct file_sdt_ent));
+ if (!fse)
+ return;
+ INIT_LIST_HEAD(&fse->file_list);
+ INIT_LIST_HEAD(&fse->sdt_list);
+ /* Obtain the file name */
+ len = copy_delim(ptr, fse->name, DELIM,
+ sizeof(fse->name), end);
+ ptr += len;
+ /* Obtain the build id */
+ len = copy_delim(ptr, fse->sbuild_id, DELIM,
+ sizeof(fse->sbuild_id), end);
+ ptr += len;
+ sdt_note__read(&ptr, &fse->sdt_list, end);
+
+ list_add(&fse->file_list, ent_head);
+
+ /* Check for another file entry */
+ if ((*ptr++ == DELIM) && (*ptr == '-'))
+ break;
+ }
+ if (ptr == end)
+ break;
+ else
+ ptr++;
+
+ } while (1);
+}
+
+/**
+ * file_hash_list__init: Initializes the file hash list
+ * @file_hash: empty file_hash
+ *
+ * Opens the cache file, reads the data into 'data' and calls
+ * file_hash_list__populate() to populate the above hash list.
+ */
+static void file_hash_list__init(struct hash_list *file_hash)
+{
+ struct stat sb;
+ char *data;
+ int fd, i, ret;
+
+ for (i = 0; i < HASH_TABLE_SIZE; i++)
+ INIT_LIST_HEAD(&file_hash->ent[i].list);
+
+ fd = open(SDT_CACHE_DIR SDT_FILE_CACHE, O_RDONLY);
+ if (fd == -1)
+ return;
+
+ ret = fstat(fd, &sb);
+ if (ret == -1) {
+ pr_err("fstat : error\n");
+ return;
+ }
+
+ if (!S_ISREG(sb.st_mode)) {
+ pr_err("%s is not a regular file\n", SDT_CACHE_DIR
+ SDT_FILE_CACHE);
+ return;
+ }
+ /* Is size of the cache zero ?*/
+ if (!sb.st_size)
+ return;
+ /* Read the data */
+ data = mmap(0, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);
+ if (data == MAP_FAILED) {
+ pr_err("Error in mmap\n");
+ return;
+ }
+
+ ret = madvise(data, sb.st_size, MADV_SEQUENTIAL);
+ if (ret == -1)
+ pr_debug("Error in madvise\n");
+ ret = close(fd);
+ if (ret == -1) {
+ pr_err("Error in close\n");
+ return;
+ }
+
+ /* Populate the hash list */
+ file_hash_list__populate(file_hash, data, sb.st_size);
+ ret = munmap(data, sb.st_size);
+ if (ret == -1)
+ pr_err("Error in munmap\n");
+}
+
+/**
+ * file_hash_list__cleanup: Free up all the space for file_hash list
+ * @file_hash: file_hash table
+ */
+static void file_hash_list__cleanup(struct hash_list *file_hash)
+{
+ struct file_sdt_ent *file_pos, *tmp;
+ struct list_head *ent_head, *sdt_head;
+ int i;
+
+ /* Go through all the entries */
+ for (i = 0; i < HASH_TABLE_SIZE; i++) {
+ ent_head = &file_hash->ent[i].list;
+ if (list_empty(ent_head))
+ continue;
+
+ list_for_each_entry_safe(file_pos, tmp, ent_head, file_list) {
+ sdt_head = &file_pos->sdt_list;
+ /* Cleanup the corresponding SDT notes' list */
+ cleanup_sdt_note_list(sdt_head);
+ list_del(&file_pos->file_list);
+ list_del(&file_pos->sdt_list);
+ free(file_pos);
+ }
+ }
+}
+
+/**
+ * add_to_hash_list: add an entry to file_hash_list
+ * @file_hash: file hash table
+ * @target: file name
+ *
+ * Does a sanity check for the @target, finds out its build id,
+ * checks if @target is already present in file hash list. If not present,
+ * delete any stale entries with this file name (i.e., entries matching this
+ * file name but having older build ids). And then, adds the file entry to
+ * file hash list and also updates the SDT events in the event hash list.
+ */
+static int add_to_hash_list(struct hash_list *file_hash, const char *target)
+{
+ struct file_info *file;
+ int ret = 0;
+ u8 build_id[BUILD_ID_SIZE];
+
+ LIST_HEAD(sdt_notes);
+
+ file = (struct file_info *)malloc(sizeof(struct file_info));
+ if (!file)
+ return -ENOMEM;
+
+ file->name = realpath(target, NULL);
+ if (!file->name) {
+ ret = -EBADF;
+ pr_err("%s: Bad file name!\n", target);
+ goto out;
+ }
+
+ symbol__elf_init();
+ if (filename__read_build_id(file->name, &build_id,
+ sizeof(build_id)) < 0) {
+ pr_err("Couldn't read build-id in %s\n", file->name);
+ ret = -EBADF;
+ sdt_err(ret, file->name);
+ goto out;
+ }
+ build_id__sprintf(build_id, sizeof(build_id), file->sbuild_id);
+ /* File entry already exists ?*/
+ if (file_hash_list__entry_exists(file_hash, file)) {
+ pr_err("Error: SDT events for %s already exist!",
+ file->name);
+ ret = NO_MOD;
+ goto out;
+ }
+
+ /*
+ * This will also remove any stale entries (if any) from the event hash.
+ * Stale entries will have the same file name but older build ids.
+ */
+ file_hash_list__remove(file_hash, file->name);
+ ret = get_sdt_note_list(&sdt_notes, file->name);
+ if (!ret) {
+ /* Add the entry to file hash list */
+ ret = file_hash_list__add(&sdt_notes, file, file_hash);
+ } else {
+ sdt_err(ret, target);
+ }
+
+out:
+ free(file->name);
+ free(file);
+ return ret;
+}
+
+/**
+ * file_hash_list__flush: Flush the file_hash list to cache
+ * @file_hash: file_hash list
+ * @fcache: opened SDT events cache
+ *
+ * Iterate through all the entries of @file_hash and flush them
+ * onto fcache.
+ * The complete file hash list is flushed into the cache. First
+ * write the key for non-empty entry and then file entries for that
+ * key, and then the SDT notes. The delimiter used is ':'.
+ */
+static void file_hash_list__flush(struct hash_list *file_hash,
+ FILE *fcache)
+{
+ struct file_sdt_ent *file_pos;
+ struct list_head *ent_head, *sdt_head;
+ struct sdt_note *sdt_ptr;
+ int i;
+
+ /* Go through all entries */
+ for (i = 0; i < HASH_TABLE_SIZE; i++) {
+ /* Obtain the list head */
+ ent_head = &file_hash->ent[i].list;
+ /* Empty ? */
+ if (list_empty(ent_head))
+ continue;
+ /* ':' are used here as delimiters */
+ fprintf(fcache, "%d:", i);
+ list_for_each_entry(file_pos, ent_head, file_list) {
+ fprintf(fcache, "%s:", file_pos->name);
+ fprintf(fcache, "%s:", file_pos->sbuild_id);
+ sdt_head = &file_pos->sdt_list;
+ list_for_each_entry(sdt_ptr, sdt_head, note_list) {
+ fprintf(fcache, "%s:%s:%lx:%lx:",
+ sdt_ptr->provider, sdt_ptr->name,
+ sdt_ptr->addr.a64[0],
+ sdt_ptr->addr.a64[2]);
+ }
+ fprintf(fcache, ":");
+ }
+ /* '-' marks the end of entries for that key */
+ fprintf(fcache, "-");
+ }
+
+}
+
+/**
+ * flush_hash_list_to_cache: Flush everything from file_hash to disk
+ * @file_hash: file_hash list
+ *
+ * Opens a cache and calls file_hash_list__flush() to dump everything
+ * on to the cache.
+ */
+static void flush_hash_list_to_cache(struct hash_list *file_hash)
+{
+ FILE *cache;
+ int ret;
+ struct stat buf;
+
+ ret = stat(SDT_CACHE_DIR, &buf);
+ if (ret) {
+ ret = mkdir(SDT_CACHE_DIR, buf.st_mode);
+ if (ret) {
+ pr_err("%s : %s\n", SDT_CACHE_DIR, strerror(errno));
+ return;
+ }
+ }
+
+ cache = fopen(SDT_CACHE_DIR SDT_FILE_CACHE, "w");
+ if (!cache) {
+ pr_err("Error in creating %s file!\n",
+ SDT_CACHE_DIR SDT_FILE_CACHE);
+ return;
+ }
+
+ file_hash_list__flush(file_hash, cache);
+ fclose(cache);
+}
+
+/**
+ * add_sdt_events: Add SDT events
+ * @arg: filename
+ *
+ * Initializes a hash table 'file_hash', calls add_to_hash_list() to add SDT
+ * events of @arg to the cache and then cleans them up.
+ * 'file_hash' list is a hash table which maintains all the information
+ * related to the files with the SDT events in them. The file name serves as the
+ * key to this hash list. Each entry of the file_hash table is a list head
+ * which contains a chain of 'file_list' entries. Each 'file_list' entry contains
+ * the list of SDT events found in that file. This hash serves as a mapping
+ * from file name to the SDT events. 'file_hash' is used to add/del SDT events
+ * to the SDT cache.
+ */
+int add_sdt_events(const char *arg)
+{
+ struct hash_list file_hash;
+ int ret;
+
+ if (!arg) {
+ pr_err("Error : File Name must be specified with \"--add\""
+ "option!\n"
+ "Usage :\n perf sdt-cache --add <file-name>\n");
+ return -1;
+ }
+ /* Initialize the file hash_list */
+ file_hash_list__init(&file_hash);
+
+ /* Try to add the events to the file hash_list */
+ ret = add_to_hash_list(&file_hash, arg);
+ switch (ret) {
+ case MOD:
+ /* file hash table is dirty, flush it */
+ flush_hash_list_to_cache(&file_hash);
+ case NO_MOD:
+ /* file hash isn't dirty, do not flush */
+ file_hash_list__cleanup(&file_hash);
+ ret = 0;
+ break;
+ default:
+ file_hash_list__cleanup(&file_hash);
+ }
+ return ret;
+}
diff --git a/tools/perf/util/sdt.h b/tools/perf/util/sdt.h
new file mode 100644
index 0000000..4ed27d7
--- /dev/null
+++ b/tools/perf/util/sdt.h
@@ -0,0 +1,30 @@
+#include "build-id.h"
+
+#define HASH_TABLE_SIZE 2063
+#define SDT_CACHE_DIR "/var/cache/perf/"
+#define SDT_FILE_CACHE "perf-sdt-file.cache"
+#define SDT_EVENT_CACHE "perf-sdt-event.cache"
+
+#define DELIM ':'
+#define MAX_ADDR 17
+
+#define MOD 1
+#define NO_MOD 2
+
+struct file_sdt_ent {
+ char name[PATH_MAX]; /* file name */
+ char sbuild_id[BUILD_ID_SIZE * 2 + 1]; /* Build id of the file */
+ struct list_head file_list;
+ struct list_head sdt_list; /* SDT notes in this file */
+
+};
+
+/* hash table entry */
+struct hash_ent {
+ struct list_head list;
+};
+
+/* Hash table struct */
+struct hash_list {
+ struct hash_ent ent[HASH_TABLE_SIZE];
+};
This patch adds support to dump the SDT cache onto sdtout.
The cache data is read into a hash_list and then, it iterates through
the hash_list to dump the data onto stdout.
# ./perf sdt-cache --dump
/usr/lib64/libc-2.16.so :
%libc:lll_futex_wake
%libc:longjmp_target
%libc:longjmp
%libc:lll_lock_wait_private
%libc:lll_futex_wake
%libc:longjmp_target
%libc:longjmp
%libc:setjmp
Signed-off-by: Hemant Kumar <[email protected]>
---
tools/perf/builtin-sdt-cache.c | 26 +++++++++++++++++++++-
tools/perf/util/parse-events.h | 1 +
tools/perf/util/sdt.c | 47 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 73 insertions(+), 1 deletion(-)
diff --git a/tools/perf/builtin-sdt-cache.c b/tools/perf/builtin-sdt-cache.c
index 3c30829..c4acb91 100644
--- a/tools/perf/builtin-sdt-cache.c
+++ b/tools/perf/builtin-sdt-cache.c
@@ -15,6 +15,7 @@
/* Session management structure */
static struct {
bool add;
+ bool dump;
const char *target;
} params;
@@ -27,6 +28,15 @@ static int opt_add_sdt_events(const struct option *opt __maybe_unused,
return 0;
}
+static int opt_show_sdt_events(const struct option *opt __maybe_unused,
+ const char *str, int unset __maybe_unused)
+{
+ if (str)
+ pr_err("Unknown option %s\n", str);
+ params.dump = true;
+ return 0;
+}
+
int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused)
{
int ret;
@@ -34,10 +44,13 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused
OPT_CALLBACK('a', "add", NULL, "filename",
"add SDT events from a file.",
opt_add_sdt_events),
+ OPT_CALLBACK_NOOPT('s', "dump", NULL, "show SDT events",
+ "Read SDT events from cache and display.",
+ opt_show_sdt_events),
OPT_END()
};
const char * const sdt_cache_usage[] = {
- "perf sdt_cache --add filename",
+ "perf sdt_cache [--add filename | --dump]",
NULL
};
@@ -49,9 +62,20 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused
symbol__elf_init();
if (params.add) {
+ if (params.dump) {
+ pr_err("Error: Don't use --dump with --add\n");
+ usage_with_options(sdt_cache_usage, sdt_cache_options);
+ }
ret = add_sdt_events(params.target);
if (ret < 0)
pr_err("Cannot add SDT events to cache!\n");
+ } else if (params.dump) {
+ if (argc == 0) {
+ ret = dump_sdt_events();
+ if (ret < 0)
+ pr_err("Cannot dump SDT event cache!\n");
+ } else
+ usage_with_options(sdt_cache_usage, sdt_cache_options);
} else
usage_with_options(sdt_cache_usage, sdt_cache_options);
return 0;
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index e6efe2c..f43e6aa 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -110,5 +110,6 @@ extern int is_valid_tracepoint(const char *event_string);
extern int valid_debugfs_mount(const char *debugfs);
int add_sdt_events(const char *file);
+int dump_sdt_events(void);
#endif /* __PERF_PARSE_EVENTS_H */
diff --git a/tools/perf/util/sdt.c b/tools/perf/util/sdt.c
index 0b56210..8c3a5a5 100644
--- a/tools/perf/util/sdt.c
+++ b/tools/perf/util/sdt.c
@@ -663,3 +663,50 @@ int add_sdt_events(const char *arg)
}
return ret;
}
+
+/**
+ * file_hash_list__display: Dump the entries of file_hash list
+ * @file_hash: file hash list
+ *
+ * Iterate through each of the entries and the chains and dump
+ * onto stdscr.
+ */
+static void file_hash_list__display(struct hash_list *file_hash)
+{
+ struct file_sdt_ent *file_pos;
+ struct list_head *ent_head, *sdt_head;
+ struct sdt_note *sdt_pos;
+ int i;
+
+ for (i = 0; i < HASH_TABLE_SIZE; i++) {
+ /* Get the list_head for this entry */
+ ent_head = &file_hash->ent[i].list;
+ /* No entries ?*/
+ if (list_empty(ent_head))
+ continue;
+
+ /* Iterate through the chain in this entry */
+ list_for_each_entry(file_pos, ent_head, file_list) {
+ printf("%s :\n", file_pos->name);
+ /* Get he SDT events' head */
+ sdt_head = &file_pos->sdt_list;
+ list_for_each_entry(sdt_pos, sdt_head, note_list) {
+ printf("\t%%%s:%s\n", sdt_pos->provider,
+ sdt_pos->name);
+ }
+ printf("\n");
+ }
+ }
+}
+
+/**
+ * dump_sdt_events: Dump the SDT events on stdout
+ */
+int dump_sdt_events(void)
+{
+ struct hash_list file_hash;
+
+ file_hash_list__init(&file_hash);
+ file_hash_list__display(&file_hash);
+ return 0;
+}
This patch adds the support to delete SDT events from the cache.
To delete an event corresponding to a file, first the cache is read into
the file_hash list. The key is calculated from the file name.
And then, the file_list for that file_hash entry is traversed to find out
the target file_list entry. Once, it is found, its contents are all freed up.
# ./perf sdt-cache --del /usr/lib64/libc-2.16.so
8 events removed for /usr/lib64/libc-2.16.so!
Signed-off-by: Hemant Kumar <[email protected]>
---
tools/perf/builtin-sdt-cache.c | 28 +++++++++++++++++++++++++++-
tools/perf/util/parse-events.h | 1 +
tools/perf/util/sdt.c | 35 +++++++++++++++++++++++++++++++++++
3 files changed, 63 insertions(+), 1 deletion(-)
diff --git a/tools/perf/builtin-sdt-cache.c b/tools/perf/builtin-sdt-cache.c
index c4acb91..6341e17 100644
--- a/tools/perf/builtin-sdt-cache.c
+++ b/tools/perf/builtin-sdt-cache.c
@@ -15,6 +15,7 @@
/* Session management structure */
static struct {
bool add;
+ bool del;
bool dump;
const char *target;
} params;
@@ -28,6 +29,15 @@ static int opt_add_sdt_events(const struct option *opt __maybe_unused,
return 0;
}
+static int opt_del_sdt_events(const struct option *opt __maybe_unused,
+ const char *str, int unset __maybe_unused)
+{
+ params.del = true;
+ params.target = str;
+
+ return 0;
+}
+
static int opt_show_sdt_events(const struct option *opt __maybe_unused,
const char *str, int unset __maybe_unused)
{
@@ -44,13 +54,17 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused
OPT_CALLBACK('a', "add", NULL, "filename",
"add SDT events from a file.",
opt_add_sdt_events),
+ OPT_CALLBACK('d', "del", NULL, "filename",
+ "Remove SDT events corresponding to a file from the"
+ " sdt cache.",
+ opt_del_sdt_events),
OPT_CALLBACK_NOOPT('s', "dump", NULL, "show SDT events",
"Read SDT events from cache and display.",
opt_show_sdt_events),
OPT_END()
};
const char * const sdt_cache_usage[] = {
- "perf sdt_cache [--add filename | --dump]",
+ "perf sdt_cache [--add filename | --del filename | --dump]",
NULL
};
@@ -62,6 +76,10 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused
symbol__elf_init();
if (params.add) {
+ if (params.del) {
+ pr_err("Error: Don't use --del with --add\n");
+ usage_with_options(sdt_cache_usage, sdt_cache_options);
+ }
if (params.dump) {
pr_err("Error: Don't use --dump with --add\n");
usage_with_options(sdt_cache_usage, sdt_cache_options);
@@ -69,6 +87,14 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused
ret = add_sdt_events(params.target);
if (ret < 0)
pr_err("Cannot add SDT events to cache!\n");
+ } else if (params.del) {
+ if (params.dump) {
+ pr_err("Error: Don't use --dump with --del\n");
+ usage_with_options(sdt_cache_usage, sdt_cache_options);
+ }
+ ret = remove_sdt_events(params.target);
+ if (ret < 0)
+ pr_err("Cannot remove SDT events from cache!\n");
} else if (params.dump) {
if (argc == 0) {
ret = dump_sdt_events();
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index f43e6aa..2297af7 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -111,5 +111,6 @@ extern int valid_debugfs_mount(const char *debugfs);
int add_sdt_events(const char *file);
int dump_sdt_events(void);
+int remove_sdt_events(const char *str);
#endif /* __PERF_PARSE_EVENTS_H */
diff --git a/tools/perf/util/sdt.c b/tools/perf/util/sdt.c
index 8c3a5a5..88c53b5 100644
--- a/tools/perf/util/sdt.c
+++ b/tools/perf/util/sdt.c
@@ -710,3 +710,38 @@ int dump_sdt_events(void)
file_hash_list__display(&file_hash);
return 0;
}
+
+/**
+ * remove_sdt_events: remove SDT events from cache
+ * @str: filename
+ *
+ * Removes the SDT events from the cache corresponding to the file name
+ * @str.
+ */
+int remove_sdt_events(const char *str)
+{
+ struct hash_list file_hash;
+ char *res_path;
+ int nr_del;
+
+ /* Initialize the hash_lists */
+ file_hash_list__init(&file_hash);
+ res_path = realpath(str, NULL);
+ if (!res_path)
+ return -ENOMEM;
+
+ /* Remove the file_list entry from file_hash and update the event_hash */
+ nr_del = file_hash_list__remove(&file_hash, res_path);
+ if (nr_del > 0) {
+ printf("%d events removed for %s!\n", nr_del, res_path);
+ flush_hash_list_to_cache(&file_hash);
+ goto out;
+ } else if (!nr_del) {
+ pr_err("Events for %s not found!\n", str);
+ }
+
+out:
+ free(res_path);
+ file_hash_list__cleanup(&file_hash);
+ return nr_del;
+}
The SDT events are already stored in a cache file
(/var/cache/perf/perf-sdt-file.cache).
Although the file_hash table helps in addition or deletion of SDT events from the
cache, its not of much use when it comes to probing the actual SDT event, because the
key to this hash list is a file name and not the SDT event name (which is given as
an argument to perf record). So, we won't be able to hash into it.
To avoid this problem, we can create another hash list
"event_hash" list which will be maintained along with the file_hash list.
Whenever a user invokes 'perf record -e %provider:event, perf should initialize
the event_hash list and the file_hash list.
The key to event_hash list is calculated from the event name and its
provider name.
event_hash sdt_note
|---------| ----------------
| | | file_ptr |==> to file_sdt_ent containing this note
key = 129 =>| list ==|===|=> event_list=|==> to other sdt notes hashed to same entry
| | | name |
|---------| | provider |
| | | note_list==|==> to other notes in the same file
key = 130 =>| list | ---------------
|---------|
The entry at that key in event_hash contains a list of SDT notes hashed to the
same entry. It compares the name and provider to see if that is the SDT note we
are looking for. If yes, find out the file that contains this SDT note. There is
a file_ptr pointer embedded in this note which points to the struct file_sdt_ent
contained in the file_hash. From "file_sdt_ent" we will find out the file name.
Convert this sdt note into a perf event and then write this into uprobe_events
file to be able to record the event.
Then, corresponding entries are added to uprobe_events file for
the SDT events.
After recording is done, these events are silently deleted from uprobe_events
file. The uprobe_events file is present in debugfs/tracing directory.
To support the addition and deletion of SDT events to/from uprobe_events
file, a record_sdt struct is maintained which has the event data.
An example usage:
# ./perf record -e %user_app:fun_start -aR /home/user_app
In main
This is foo
This is fun
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.265 MB perf.data (~11581 samples) ]
# ./perf report --stdio
...
# To display the perf.data header info, please use --header/--header-only options.
#
# Samples: 1 of event 'user_app:fun_start'
# Event count (approx.): 1
#
# Overhead Command Shared Object Symbol
# ........ ........ ............. .......
#
100.00% user_app user_app [.] fun
Multiple events can also be recorded simultaneously.
Signed-off-by: Hemant Kumar <[email protected]>
---
tools/perf/builtin-record.c | 21 ++++
tools/perf/util/parse-events.c | 7 +
tools/perf/util/parse-events.h | 3 +
tools/perf/util/probe-event.c | 120 ++++++++++++++++++++-----
tools/perf/util/probe-event.h | 7 +
tools/perf/util/probe-finder.c | 3 +
tools/perf/util/sdt.c | 194 ++++++++++++++++++++++++++++++++++++++--
tools/perf/util/symbol.h | 2
8 files changed, 327 insertions(+), 30 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 378b85b..f573a4b 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -45,6 +45,25 @@ struct record {
long samples;
};
+/* Session specific to SDT tracing */
+struct record_sdt {
+ bool sdt; /* is this SDT event tracing? */
+ char *str; /* hold the event name */
+} rec_sdt;
+
+int trace_sdt_event(const char *str)
+{
+ int ret = 0;
+
+ rec_sdt.sdt = true;
+ rec_sdt.str = strdup(str);
+ if (!rec_sdt.str)
+ return -ENOMEM;
+ ret = event_hash_list__lookup(str);
+
+ return ret;
+}
+
static int record__write(struct record *rec, void *bf, size_t size)
{
if (perf_data_file__write(rec->session->file, bf, size) < 0) {
@@ -953,6 +972,8 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
}
err = __cmd_record(&record, argc, argv);
+ if (rec_sdt.sdt)
+ err = remove_perf_sdt_events(rec_sdt.str);
out_symbol_exit:
perf_evlist__delete(rec->evlist);
symbol__exit();
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 1e15df1..b2db9e3 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -890,6 +890,13 @@ static int parse_events__scanner(const char *str, void *data, int start_token)
buffer = parse_events__scan_string(str, scanner);
+ /* '%' means it can be an SDT event */
+ if (*str == '%')
+ if (strchr(str, ':')) {
+ ret = event_hash_list__lookup(str);
+ str++;
+ }
+
#ifdef PARSER_DEBUG
parse_events_debug = 1;
#endif
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 2297af7..52a163a 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -112,5 +112,8 @@ extern int valid_debugfs_mount(const char *debugfs);
int add_sdt_events(const char *file);
int dump_sdt_events(void);
int remove_sdt_events(const char *str);
+int event_hash_list__lookup(const char *str);
+int remove_perf_sdt_events(const char *str);
+int trace_sdt_event(const char *str);
#endif /* __PERF_PARSE_EVENTS_H */
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 9a0a183..114c5de 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -353,7 +353,8 @@ error:
}
static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
- int ntevs, const char *exec)
+ int ntevs, const char *exec,
+ struct perf_probe_event *pev)
{
int i, ret = 0;
unsigned long stext = 0;
@@ -367,7 +368,10 @@ static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
for (i = 0; i < ntevs && ret >= 0; i++) {
/* point.address is the addres of point.symbol + point.offset */
- tevs[i].point.address -= stext;
+ if (pev->sdt)
+ tevs[i].point.address = pev->point.offset;
+ else
+ tevs[i].point.address -= stext;
tevs[i].point.module = strdup(exec);
if (!tevs[i].point.module) {
ret = -ENOMEM;
@@ -415,14 +419,14 @@ static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
/* Post processing the probe events */
static int post_process_probe_trace_events(struct probe_trace_event *tevs,
int ntevs, const char *module,
- bool uprobe)
+ struct perf_probe_event *pev)
{
struct ref_reloc_sym *reloc_sym;
char *tmp;
int i;
- if (uprobe)
- return add_exec_to_probe_trace_events(tevs, ntevs, module);
+ if (pev->uprobes)
+ return add_exec_to_probe_trace_events(tevs, ntevs, module, pev);
/* Note that currently ref_reloc_sym based probe is not for drivers */
if (module)
@@ -477,7 +481,7 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
if (ntevs > 0) { /* Succeeded to find trace events */
pr_debug("Found %d probe_trace_events.\n", ntevs);
ret = post_process_probe_trace_events(*tevs, ntevs,
- target, pev->uprobes);
+ target, pev);
if (ret < 0) {
clear_probe_trace_events(*tevs, ntevs);
zfree(tevs);
@@ -1108,6 +1112,43 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
return 0;
}
+/* Parse an SDT event */
+static int parse_perf_sdt_event(struct perf_sdt_event *sev,
+ struct perf_probe_event *pev)
+{
+ struct perf_probe_point *pp = &pev->point;
+
+ pev->uprobes = true;
+ pev->sdt = true;
+ pev->event = strdup(sev->note->name);
+ if (pev->event == NULL)
+ return -ENOMEM;
+ pev->group = strdup(sev->note->provider);
+ if (pev->event == NULL)
+ return -ENOMEM;
+
+ pp->file = strdup(sev->file_name);
+ if (pp->file == NULL)
+ return -ENOMEM;
+
+ pp->function = strdup(sev->note->name);
+ pp->offset = sev->note->addr.a64[0];
+ return 0;
+}
+
+int add_perf_sdt_event(struct perf_sdt_event *sev)
+{
+ struct perf_probe_event pev;
+ int ret;
+
+ ret = parse_perf_sdt_event(sev, &pev);
+ if (!ret)
+ add_perf_probe_events(&pev, 1, MAX_PROBES,
+ sev->file_name, true);
+
+ return ret;
+}
+
/* Parse perf-probe event argument */
static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
{
@@ -1884,9 +1925,12 @@ static int show_perf_probe_event(struct perf_probe_event *pev,
if (ret < 0)
return ret;
- printf(" %-20s (on %s", buf, place);
- if (module)
- printf(" in %s", module);
+ /* Do not display anything for SDTs */
+ if (!pev->sdt) {
+ printf(" %-20s (on %s", buf, place);
+ if (module)
+ printf(" in %s", module);
+ }
if (pev->nargs > 0) {
printf(" with");
@@ -1898,7 +1942,9 @@ static int show_perf_probe_event(struct perf_probe_event *pev,
printf(" %s", buf);
}
}
- printf(")\n");
+ /* Not for SDT events */
+ if (!pev->sdt)
+ printf(")\n");
free(place);
return ret;
}
@@ -2085,7 +2131,9 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
}
ret = 0;
- printf("Added new event%s\n", (ntevs > 1) ? "s:" : ":");
+ /* If SDT event, do not print anything */
+ if (!pev->sdt)
+ printf("Added new event%s\n", (ntevs > 1) ? "s:" : ":");
for (i = 0; i < ntevs; i++) {
tev = &tevs[i];
if (pev->event)
@@ -2124,6 +2172,12 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
group = pev->group;
pev->event = tev->event;
pev->group = tev->group;
+
+ /* Arguments currently not supported with SDT events */
+ if (pev->sdt) {
+ pev->nargs = 0;
+ tev->nargs = 0;
+ }
show_perf_probe_event(pev, tev->point.module);
/* Trick here - restore current event/group */
pev->event = (char *)event;
@@ -2138,8 +2192,8 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
allow_suffix = true;
}
- if (ret >= 0) {
- /* Show how to use the event. */
+ if (ret >= 0 && !pev->sdt) {
+ /* Show how to use the event except for SDT events */
printf("\nYou can now use it in all perf tools, such as:\n\n");
printf("\tperf record -e %s:%s -aR sleep 1\n\n", tev->group,
tev->event);
@@ -2332,6 +2386,7 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,
{
int i, j, ret;
struct __event_package *pkgs;
+ bool sdt = pevs->sdt;
ret = 0;
pkgs = zalloc(sizeof(struct __event_package) * npevs);
@@ -2373,12 +2428,13 @@ end:
zfree(&pkgs[i].tevs);
}
free(pkgs);
- exit_symbol_maps();
+ if (!sdt) /* We didn't initialize symbol maps for SDT events */
+ exit_symbol_maps();
return ret;
}
-static int __del_trace_probe_event(int fd, struct str_node *ent)
+static int __del_trace_probe_event(int fd, struct str_node *ent, bool sdt)
{
char *p;
char buf[128];
@@ -2405,7 +2461,8 @@ static int __del_trace_probe_event(int fd, struct str_node *ent)
goto error;
}
- printf("Removed event: %s\n", ent->s);
+ if (!sdt)
+ printf("Removed event: %s\n", ent->s);
return 0;
error:
pr_warning("Failed to delete event: %s\n", strerror(-ret));
@@ -2413,7 +2470,8 @@ error:
}
static int del_trace_probe_event(int fd, const char *buf,
- struct strlist *namelist)
+ struct strlist *namelist,
+ bool sdt)
{
struct str_node *ent, *n;
int ret = -1;
@@ -2421,7 +2479,7 @@ static int del_trace_probe_event(int fd, const char *buf,
if (strpbrk(buf, "*?")) { /* Glob-exp */
strlist__for_each_safe(ent, n, namelist)
if (strglobmatch(ent->s, buf)) {
- ret = __del_trace_probe_event(fd, ent);
+ ret = __del_trace_probe_event(fd, ent, sdt);
if (ret < 0)
break;
strlist__remove(namelist, ent);
@@ -2429,7 +2487,7 @@ static int del_trace_probe_event(int fd, const char *buf,
} else {
ent = strlist__find(namelist, buf);
if (ent) {
- ret = __del_trace_probe_event(fd, ent);
+ ret = __del_trace_probe_event(fd, ent, sdt);
if (ret >= 0)
strlist__remove(namelist, ent);
}
@@ -2438,7 +2496,7 @@ static int del_trace_probe_event(int fd, const char *buf,
return ret;
}
-int del_perf_probe_events(struct strlist *dellist)
+static int __del_perf_probe_events(struct strlist *dellist, bool sdt)
{
int ret = -1, ufd = -1, kfd = -1;
char buf[128];
@@ -2488,10 +2546,10 @@ int del_perf_probe_events(struct strlist *dellist)
pr_debug("Group: %s, Event: %s\n", group, event);
if (namelist)
- ret = del_trace_probe_event(kfd, buf, namelist);
+ ret = del_trace_probe_event(kfd, buf, namelist, sdt);
if (unamelist && ret != 0)
- ret = del_trace_probe_event(ufd, buf, unamelist);
+ ret = del_trace_probe_event(ufd, buf, unamelist, sdt);
if (ret != 0)
pr_info("Info: Event \"%s\" does not exist.\n", buf);
@@ -2513,6 +2571,24 @@ error:
return ret;
}
+int del_perf_probe_events(struct strlist *dellist)
+{
+ return __del_perf_probe_events(dellist, false);
+}
+
+int remove_perf_sdt_events(const char *str)
+{
+ struct strlist *dellist;
+ int ret = 0;
+
+ dellist = strlist__new(true, NULL);
+ strlist__add(dellist, str + 1);
+ if (dellist)
+ ret = __del_perf_probe_events(dellist, true);
+
+ return ret;
+}
+
/* TODO: don't use a global variable for filter ... */
static struct strfilter *available_func_filter;
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 5ba93c6..67d0809 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -75,9 +75,15 @@ struct perf_probe_event {
struct perf_probe_point point; /* Probe point */
int nargs; /* Number of arguments */
bool uprobes;
+ bool sdt; /* An SDT event? */
struct perf_probe_arg *args; /* Arguments */
};
+struct perf_sdt_event {
+ struct sdt_note *note; /* SDT note info */
+ char *file_name; /* File name */
+};
+
/* Line range */
struct line_range {
char *file; /* File name */
@@ -135,6 +141,7 @@ extern int show_available_vars(struct perf_probe_event *pevs, int npevs,
struct strfilter *filter, bool externs);
extern int show_available_funcs(const char *module, struct strfilter *filter,
bool user);
+extern int add_perf_sdt_event(struct perf_sdt_event *sev);
/* Maximum index number of event-name postfix */
#define MAX_EVENT_INDEX 1024
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 98e3047..9920653 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1191,6 +1191,9 @@ int debuginfo__find_trace_events(struct debuginfo *dbg,
tf.tevs = *tevs;
tf.ntevs = 0;
+ /* Number of trace events for SDT event is 1 */
+ if (pev->sdt)
+ return 1;
ret = debuginfo__find_probes(dbg, &tf.pf);
if (ret < 0) {
zfree(tevs);
diff --git a/tools/perf/util/sdt.c b/tools/perf/util/sdt.c
index 88c53b5..983c7a9 100644
--- a/tools/perf/util/sdt.c
+++ b/tools/perf/util/sdt.c
@@ -328,6 +328,50 @@ static void sdt_note__read(char **ptr, struct list_head *sdt_list, char *end)
}
/**
+ * event_hash_list__add : add SDT events to event hash table
+ * @fse: obtained from the file_hash
+ * @event_hash: event hash list
+ *
+ * Iterate through the SDT notes list one by one and add them
+ * to event hash table.
+ */
+static int event_hash_list__add(struct file_sdt_ent *fse,
+ struct hash_list *event_hash)
+{
+ struct list_head *ent_head;
+ struct sdt_note *sn;
+ int event_key, nr_add = 0, len;
+ char *str;
+
+ /* Iterate through the sdt notes and add them to the event hash */
+ list_for_each_entry(sn, &fse->sdt_list, note_list) {
+ /*
+ * Assign the file_ptr so that we can always find its containing
+ * file
+ */
+ sn->file_ptr = fse;
+
+ len = strlen(sn->provider) + strlen(sn->name);
+ str = (char *)malloc(len + 1);
+ if (!str)
+ return -ENOMEM;
+
+ memset(str, '\0', len + 1);
+ /* Concatenate SDT name and provider and find out the key */
+ strcat(str, sn->provider);
+ strcat(str, sn->name);
+ event_key = get_hash_key(str);
+ free(str);
+ /* List adding */
+ ent_head = &event_hash->ent[event_key].list;
+ list_add(&sn->event_list, ent_head);
+ nr_add++;
+ }
+
+ return nr_add;
+}
+
+/**
* file_hash_list__populate: Fill up the file hash table
* @file_hash: empty file hash table
* @data: raw cache data
@@ -339,14 +383,15 @@ static void sdt_note__read(char **ptr, struct list_head *sdt_list, char *end)
* read the SDT notes. Multiple entries for the same key are delimited
* by "::". Then, it assigns the file name, build id and SDT notes to the
* list entry corresponding to 'key'.
+ * Checks if we need to add to the event_hash list.
*/
static void file_hash_list__populate(struct hash_list *file_hash, char *data,
- off_t size)
+ off_t size, struct hash_list *event_hash)
{
struct list_head *ent_head;
struct file_sdt_ent *fse;
char *end, tmp[PATH_MAX], *ptr;
- int key, len = 0;
+ int key, len = 0, ret;
end = data + size - 1;
ptr = data;
@@ -378,6 +423,12 @@ static void file_hash_list__populate(struct hash_list *file_hash, char *data,
list_add(&fse->file_list, ent_head);
+ /* See if we need to add to the event_hash */
+ if (event_hash) {
+ ret = event_hash_list__add(fse, event_hash);
+ if (ret < 0)
+ break;
+ }
/* Check for another file entry */
if ((*ptr++ == DELIM) && (*ptr == '-'))
break;
@@ -396,8 +447,10 @@ static void file_hash_list__populate(struct hash_list *file_hash, char *data,
*
* Opens the cache file, reads the data into 'data' and calls
* file_hash_list__populate() to populate the above hash list.
+ * Updates the event_hash if needed.
*/
-static void file_hash_list__init(struct hash_list *file_hash)
+static void file_hash_list__init(struct hash_list *file_hash,
+ struct hash_list *event_hash)
{
struct stat sb;
char *data;
@@ -440,14 +493,26 @@ static void file_hash_list__init(struct hash_list *file_hash)
return;
}
- /* Populate the hash list */
- file_hash_list__populate(file_hash, data, sb.st_size);
+ /* Populate the hash list(s) */
+ file_hash_list__populate(file_hash, data, sb.st_size, event_hash);
ret = munmap(data, sb.st_size);
if (ret == -1)
pr_err("Error in munmap\n");
}
/**
+ * event_hash_list__init: Initialize the event_hash list
+ * @event_hash: event_hash ptr
+ */
+static void event_hash_list__init(struct hash_list *event_hash)
+{
+ int i;
+
+ for (i = 0; i < HASH_TABLE_SIZE; i++)
+ INIT_LIST_HEAD(&event_hash->ent[i].list);
+}
+
+/**
* file_hash_list__cleanup: Free up all the space for file_hash list
* @file_hash: file_hash table
*/
@@ -475,6 +540,23 @@ static void file_hash_list__cleanup(struct hash_list *file_hash)
}
/**
+ * init_hash_lists: Initialize the hash_lists
+ * @file_hash: file_hash ptr
+ * @event_hash: event_hash ptr
+ *
+ * Wrapper function to initialize both the hash lists.
+ */
+static void init_hash_lists(struct hash_list *file_hash,
+ struct hash_list *event_hash)
+{
+ if (event_hash)
+ event_hash_list__init(event_hash);
+
+ /* event_hash gets updated in file_hash too */
+ file_hash_list__init(file_hash, event_hash);
+}
+
+/**
* add_to_hash_list: add an entry to file_hash_list
* @file_hash: file hash table
* @target: file name
@@ -645,7 +727,7 @@ int add_sdt_events(const char *arg)
return -1;
}
/* Initialize the file hash_list */
- file_hash_list__init(&file_hash);
+ init_hash_lists(&file_hash, NULL);
/* Try to add the events to the file hash_list */
ret = add_to_hash_list(&file_hash, arg);
@@ -706,7 +788,7 @@ int dump_sdt_events(void)
{
struct hash_list file_hash;
- file_hash_list__init(&file_hash);
+ init_hash_lists(&file_hash, NULL);
file_hash_list__display(&file_hash);
return 0;
}
@@ -725,7 +807,7 @@ int remove_sdt_events(const char *str)
int nr_del;
/* Initialize the hash_lists */
- file_hash_list__init(&file_hash);
+ init_hash_lists(&file_hash, NULL);
res_path = realpath(str, NULL);
if (!res_path)
return -ENOMEM;
@@ -745,3 +827,99 @@ out:
file_hash_list__cleanup(&file_hash);
return nr_del;
}
+
+/**
+ * convert_to_sdt_event : Converts a SDT note into a perf consumable event
+ * @sn: sdt note
+ * @sdt_event: converted sdt_event
+ *
+ * Copies the file name and assigns a reference to @sn to @sdt_event->note
+ */
+static int convert_to_sdt_event(struct sdt_note *sn,
+ struct perf_sdt_event *sdt_event)
+{
+ sdt_event->file_name = strdup(sn->file_ptr->name);
+ if (!sdt_event->file_name) {
+ pr_err("Error: Not enough memory!");
+ return -ENOMEM;
+ }
+ sdt_event->note = sn;
+
+ return 0;
+}
+
+/**
+ * event_hash_list__lookup: Function to lookup an SDT event
+ * @str: provider:name
+ *
+ * file_hash list is not designed to lookup for an SDT event. To do that, we
+ * need another structure : "event_hash". This hash list is built up along
+ * with file_hash list but is based on SDT event names as keys as opposed to
+ * the file names (who serve as keys in file_hash list).
+ * To lookup for the SDT event name, initialize file_hash list first along
+ * with the event_hash. init_hash_lists() will do that for us. Now, obtain
+ * the key for event_hash using @str (provider:name). Go to that entry,
+ * obtain the list_head for that entry, start traversing the list of events.
+ * Once, we get the SDT note we were looking for, change the SDT note to a
+ * perf consumable event.
+ */
+int event_hash_list__lookup(const char *str)
+{
+ struct hash_list file_hash, event_hash;
+ struct sdt_note *sn;
+ struct perf_sdt_event *sdt_event = NULL;
+ struct list_head *ent_head;
+ int event_key, ret = 0, len;
+ char group[PATH_MAX], event[PATH_MAX], *ptr;
+
+ /* Initialize the hash_lists */
+ init_hash_lists(&file_hash, &event_hash);
+
+ ptr = strdup(str);
+ if (!ptr) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ /* Get the SDT provider name */
+ len = copy_delim(ptr + 1, group, DELIM, strlen(str),
+ strchr(str, ':'));
+ /* Get the SDT event name */
+ strcpy(event, str + len + 1);
+ /* str + 1 to get rid of leading % */
+ memset(ptr, '\0', strlen(ptr));
+ strcat(ptr, group);
+ strcat(ptr, event);
+ /* Calculate the event hash key */
+ event_key = get_hash_key(ptr);
+ ent_head = &event_hash.ent[event_key].list;
+ if (list_empty(ent_head)) {
+ /* No events at this entry, get out */
+ ret = -1;
+ goto out;
+ }
+
+ /* Found event(s) */
+ list_for_each_entry(sn, ent_head, event_list) {
+ if (!strcmp(sn->name, event) && !strcmp(sn->provider, group)) {
+ sdt_event = (struct perf_sdt_event *)malloc
+ (sizeof(struct perf_sdt_event));
+ if (!sdt_event) {
+ pr_err("Error: Not enough memory!");
+ ret = -ENOMEM;
+ goto out;
+ }
+ ret = convert_to_sdt_event(sn, sdt_event);
+ if (!ret)
+ /* Add the SDT event to uprobes */
+ ret = add_perf_sdt_event(sdt_event);
+ }
+ }
+
+out:
+ file_hash_list__cleanup(&file_hash);
+ if (sdt_event->file_name)
+ free(sdt_event->file_name);
+
+ return ret;
+
+}
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index cef620e..33b363d 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -304,6 +304,8 @@ struct sdt_note {
Elf32_Addr a32[3];
} addr;
struct list_head note_list; /* SDT notes' list */
+ struct list_head event_list; /* Link to event_hash_list entry */
+ struct file_sdt_ent *file_ptr; /* ptr to the containing file_sdt_ent */
};
int get_sdt_note_list(struct list_head *head, const char *target);
Hi,
(2014/10/01 0:29), Hemant Kumar wrote:
> This patchset helps in listing dtrace style markers(SDT) present in user space
> applications through perf.
> Notes/markers are placed at important places by the
> developers. They have a negligible overhead when not enabled.
> We can enable them and probe at these places and find some important information
> like the arguments' values, etc.
>
> We have lots of applications which use SDT markers today, like:
> Postgresql, MySql, Mozilla, Perl, Python, Java, Ruby, libvirt, QEMU, glib
>
> To add SDT markers into user applications:
> We need to have this header sys/sdt.h present.
> sys/sdt.h used is version 3.
> If not present, install systemtap-sdt-devel package (for fedora-20).
>
> With this patchset,
> - Use perf sdt-cache --add to add SDT events to a cache.
> # perf sdt-cache --add ./user_app
>
> 4 SDT events added for /home/user/user_app!
>
> - Use perf sdt-cache --del to remove SDT events from the cache>
> # perf sdt-cache --del ./user_app
>
> 4 events removed for /home/user/user_app!
>
> - Dump the cache onto stdout using perf sdt-cache --dump:
> # perf sdt-cache --dump
> /home/user/user_app :
> %user_app:foo_start
> %user_app:fun_start
>
> - To probe and trace an SDT event :
> # perf record -e %user_app:foo_start -aR sleep 10
Looks great! :)
However, when I've tried to build, I got below errors..
CC util/sdt.o
util/sdt.c: In function ‘sdt_err’:
util/sdt.c:72:3: error: implicit declaration of function ‘pr_err’ [-Werror=implicit-function-declaration]
pr_err("%s: No SDT events found\n", target);
^
util/sdt.c:72:3: error: nested extern declaration of ‘pr_err’ [-Werror=nested-externs]
util/sdt.c: In function ‘file_hash_list__init’:
util/sdt.c:489:3: error: implicit declaration of function ‘pr_debug’ [-Werror=implicit-function-declaration]
pr_debug("Error in madvise\n");
^
util/sdt.c:489:3: error: nested extern declaration of ‘pr_debug’ [-Werror=nested-externs]
cc1: all warnings being treated as errors
Perhaps, you might working on the old tree. Could you update it?
Thank you,
>
> The support for perf to sdt events has undergone a lot of changes since it was
> introduced. After a lot of discussions (https://lkml.org/lkml/2014/7/20/284), the
> patchset is subdivided for ease of review.
> Previously, a patchset supporting "perf list sdt" was posted, but it didn't make
> much sense since, only listing SDT events for an ELF won't help.
> This patchset aims at adding a sub-command "sdt-cache" to perf to manage a cache
> for management of the SDT events.
>
> This link shows an example of marker probing with Systemtap:
> https://sourceware.org/systemtap/wiki/AddingUserSpaceProbingToApps
>
> This link provides important info regarding SDT notes:
> http://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
>
> - Markers in binaries :
> These SDT markers are present in the ELF in the section named
> ".note.stapsdt".
> Here, the name of the marker, its provider, type, location, base
> address, semaphore address.
> We can retrieve these values using the members name_off and desc_off in
> Nhdr structure. If these are not enabled, they are present in the ELF as nop.
>
> Changes since last series :
> - Changed the entire (linked) list structure to hash lists to manage the SDT events.
> - Added a sub command "sdt-cache" to perf to manage SDT events in the system.
> - Added support to add and remove SDT events onto a cache.
> - Added support to "perf record" to probe and record the SDT events.
>
> TODO:
> - Add support to add most of the SDT events on a system to the cache.
> - Recognizing arguments and support to probe on them.
>
> ---
>
> Hemant Kumar (5):
> perf/sdt: ELF support for SDT
> perf/sdt: Add SDT events into a cache
> perf/sdt: Show SDT cache contents
> perf/sdt: Delete SDT events from cache
> perf/sdt: Add support to perf record to trace SDT events
>
>
> tools/perf/Makefile.perf | 3
> tools/perf/builtin-record.c | 21 +
> tools/perf/builtin-sdt-cache.c | 108 +++++
> tools/perf/builtin.h | 1
> tools/perf/perf.c | 1
> tools/perf/util/parse-events.c | 7
> tools/perf/util/parse-events.h | 7
> tools/perf/util/probe-event.c | 120 ++++-
> tools/perf/util/probe-event.h | 8
> tools/perf/util/probe-finder.c | 3
> tools/perf/util/sdt.c | 925 ++++++++++++++++++++++++++++++++++++++++
> tools/perf/util/sdt.h | 30 +
> tools/perf/util/symbol-elf.c | 207 +++++++++
> tools/perf/util/symbol.h | 21 +
> 14 files changed, 1440 insertions(+), 22 deletions(-)
> create mode 100644 tools/perf/builtin-sdt-cache.c
> create mode 100644 tools/perf/util/sdt.c
> create mode 100644 tools/perf/util/sdt.h
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: [email protected]
Hi Masami,
On 10/01/2014 09:38 PM, Masami Hiramatsu wrote:
> Hi,
>
> (2014/10/01 0:29), Hemant Kumar wrote:
>> This patchset helps in listing dtrace style markers(SDT) present in user space
>> applications through perf.
>> Notes/markers are placed at important places by the
>> developers. They have a negligible overhead when not enabled.
>> We can enable them and probe at these places and find some important information
>> like the arguments' values, etc.
>>
>> We have lots of applications which use SDT markers today, like:
>> Postgresql, MySql, Mozilla, Perl, Python, Java, Ruby, libvirt, QEMU, glib
>>
>> To add SDT markers into user applications:
>> We need to have this header sys/sdt.h present.
>> sys/sdt.h used is version 3.
>> If not present, install systemtap-sdt-devel package (for fedora-20).
>>
>> With this patchset,
>> - Use perf sdt-cache --add to add SDT events to a cache.
>> # perf sdt-cache --add ./user_app
>>
>> 4 SDT events added for /home/user/user_app!
>>
>> - Use perf sdt-cache --del to remove SDT events from the cache>
>> # perf sdt-cache --del ./user_app
>>
>> 4 events removed for /home/user/user_app!
>>
>> - Dump the cache onto stdout using perf sdt-cache --dump:
>> # perf sdt-cache --dump
>> /home/user/user_app :
>> %user_app:foo_start
>> %user_app:fun_start
>>
>> - To probe and trace an SDT event :
>> # perf record -e %user_app:foo_start -aR sleep 10
> Looks great! :)
Thankyou :)
>
> However, when I've tried to build, I got below errors..
>
> CC util/sdt.o
> util/sdt.c: In function ‘sdt_err’:
> util/sdt.c:72:3: error: implicit declaration of function ‘pr_err’ [-Werror=implicit-function-declaration]
> pr_err("%s: No SDT events found\n", target);
> ^
> util/sdt.c:72:3: error: nested extern declaration of ‘pr_err’ [-Werror=nested-externs]
> util/sdt.c: In function ‘file_hash_list__init’:
> util/sdt.c:489:3: error: implicit declaration of function ‘pr_debug’ [-Werror=implicit-function-declaration]
> pr_debug("Error in madvise\n");
> ^
> util/sdt.c:489:3: error: nested extern declaration of ‘pr_debug’ [-Werror=nested-externs]
> cc1: all warnings being treated as errors
>
> Perhaps, you might working on the old tree. Could you update it?
Hmm. Yes, it was on an older tree. Will update it and repost them.
> [SNIP]
>
--
Thanks,
Hemant Kumar
(2014/10/01 0:32), Hemant Kumar wrote:
> This patch adds a new sub-command to perf : sdt-cache.
When I ran perf without option, sdt-cache did not appear. You should update
command-list.txt and add Documentation/perf-sdt-cache.txt, so that sdt-cache is
shown (Note that perf build automatically extracts NAME line and embeds it as a
help message). Maybe commit ef12a141 is good to refer :)
> sdt-cache command can be used to add, remove and dump SDT events.
> This patch adds support to only "add" the SDT events. The rest of the
> patches add support to rest of them.
You don't need to describe dump and remove in this patch. How about below?
perf-sdt-cache command manages SDT events in applications. This adds
"perf sdt-cache --add <file>" to add SDT events in given file to local
cache.
> When user invokes "perf sdt-cache add <file-name>", two hash tables are
> created: file_hash list and event_hash list. A typical entry in a file_hash
> table looks like:
> file hash file_sdt_ent file_sdt_ent
> |---------| --------------- -------------
> | list ==|===|=>file_list =|===|=>file_list=|==..
> key = 644 =>| | | sbuild_id | | sbuild_id |
> |---------| | name | | name |
> | | | sdt_list | | sdt_list |
> key = 645 =>| list | | || | | || |
> |---------| --------------- --------------
> || || || Connected to SDT notes
> ---------------
> | note_list |
> sdt_note| name |
> | provider |
> -----||--------
> connected to other SDT notes
Hmm, why don't you use hlist for file_hash.list?
>
>
> Each entry of the file_hash table is a list which connects to file_list in
> file_sdt_ent. file_sdt_ent is allocated per file whenever a file is mapped
> to file_hash list. File name serves as the key to this hash table.
> If a file is added to this hash list, a file_sdt_ent is allocated and a
> list of SDT events in that file is created and assigned to sdt_list of
> file_sdt_ent.
>
> Example usage :
> # ./perf sdt-cache --add /home/user_app
>
> 4 events added for /home/user_app!
>
> # ./perf sdt-cache --add /lib64/libc.so.6
>
> 8 events added for /usr/lib64/libc-2.16.so!
IMO, when succeeding to add events, it may not need the last "!", since
it is eye-catching too much (as like as we get an error).
[...]
> diff --git a/tools/perf/util/sdt.c b/tools/perf/util/sdt.c
> new file mode 100644
> index 0000000..0b56210
> --- /dev/null
> +++ b/tools/perf/util/sdt.c
> @@ -0,0 +1,665 @@
> +/*
> + * util/sdt.c
> + * This contains the relevant functions needed to find the SDT events
> + * in a binary and adding them to a cache.
> + *
> + * TODOS:
> + * - Listing SDT events in most of the binaries present in the system.
> + * - Looking into directories provided by the user for binaries with SDTs,
> + * etc.
> + * - Support SDT event arguments.
> + * - Support SDT event semaphores.
> + */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <errno.h>
> +#include <string.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <unistd.h>
> +#include <limits.h>
> +#include <sys/mman.h>
> +#include <fcntl.h>
> +
> +#include "parse-events.h"
> +#include "probe-event.h"
> +#include "linux/list.h"
> +#include "symbol.h"
> +#include "build-id.h"
> +
> +struct file_info {
> + char *name; /* File name */
> + char sbuild_id[BUILD_ID_SIZE * 2 + 1]; /* Build id of the file */
> +};
> +
> +/**
> + * get_hash_key: calculates the key to hash tables
> + * @str: input string
> + *
> + * adds the ascii values for all the chars in @str, multiplies with a prime
> + * and finds the modulo with HASH_TABLE_SIZE.
> + *
> + * Return : An integer key
> + */
> +static unsigned get_hash_key(const char *str)
> +{
> + unsigned value = 0, key;
> + unsigned c;
> +
> + for (c = 0; str[c] != '\0'; c++)
> + value += str[c];
> +
> + key = (value * 37) % HASH_TABLE_SIZE;
37 seems to a magic number :) how about defining it as HASH_PRIME_BASE?
> +
> + return key;
> +}
> +
> +/**
> + * sdt_err: print SDT related error
> + * @val: error code
> + * @target: input file
> + *
> + * Display error corresponding to @val for file @target
> + */
> +static int sdt_err(int val, const char *target)
> +{
> + switch (-val) {
> + case 0:
> + break;
> + case ENOENT:
> + /* Absence of SDT markers */
> + pr_err("%s: No SDT events found\n", target);
> + break;
> + case EBADF:
> + pr_err("%s: Bad file name\n", target);
> + break;
> + default:
> + pr_err("%s\n", strerror(val));
> + }
> +
> + return val;
> +}
> +
> +/**
> + * cleanup_sdt_note_list : free the sdt notes' list
> + * @sdt_notes: sdt notes' list
> + *
> + * Free up the SDT notes in @sdt_notes.
> + */
> +static void cleanup_sdt_note_list(struct list_head *sdt_notes)
> +{
> + struct sdt_note *tmp, *pos;
> +
> + if (list_empty(sdt_notes))
> + return;
> +
> + list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
> + list_del(&pos->note_list);
> + free(pos->name);
> + free(pos->provider);
> + free(pos);
> + }
> +}
Hmm, since the list is created in tools/perf/util/symbol-elf.c, it is better
to be defined in the same file, and same patch(1/1).
> +
> +/**
> + * file_list_entry__init: Initialize a file_list_entry
> + * @fse: file_list_entry
> + * @file: file information
> + *
> + * Initializes @fse with the build id of a @file.
> + */
> +static void file_list_entry__init(struct file_sdt_ent *fse,
> + struct file_info *file)
> +{
> + strcpy(fse->sbuild_id, file->sbuild_id);
> + INIT_LIST_HEAD(&fse->file_list);
> + INIT_LIST_HEAD(&fse->sdt_list);
> +}
> +
> +/**
> + * sdt_events__get_count: Counts the number of sdt events
> + * @start: list_head to sdt_notes list
> + *
> + * Returns the number of SDT notes in a list
> + */
> +static int sdt_events__get_count(struct list_head *start)
> +{
> + struct sdt_note *sdt_ptr;
> + int count = 0;
> +
> + list_for_each_entry(sdt_ptr, start, note_list) {
> + count++;
> + }
> + return count;
> +}
This should be also in symbol-elf.c or symbol.h. Moreover, since there is no sdt_events
data structure, the function name looks a bit odd.
> +
> +/**
> + * file_hash_list__add: add an entry to file_hash_list
> + * @sdt_notes: list of sdt_notes
> + * @file: file name and build id
> + * @file_hash: hash table for file and sdt notes
> + *
> + * Get the key corresponding to @file->name. Fetch the entry
> + * for that key. Build a file_list_entry fse, assign the SDT notes
> + * to it and then assign fse to the fetched entry into the hash.
> + */
> +static int file_hash_list__add(struct list_head *sdt_notes,
> + struct file_info *file,
> + struct hash_list *file_hash)
> +{
> + struct file_sdt_ent *fse;
> + struct list_head *ent_head;
> + int key, nr_evs;
> +
> + key = get_hash_key(file->name);
> + ent_head = &file_hash->ent[key].list;
> +
> + /* Initialize the file entry */
> + fse = (struct file_sdt_ent *)malloc(sizeof(struct file_sdt_ent));
> + if (!fse)
> + return -ENOMEM;
> + file_list_entry__init(fse, file);
> + nr_evs = sdt_events__get_count(sdt_notes);
> + list_splice(sdt_notes, &fse->sdt_list);
> +
> + printf("%d events added for %s\n", nr_evs, file->name);
> + strcpy(fse->name, file->name);
> +
> + /* Add the file to the file hash entry */
> + list_add(&fse->file_list, ent_head);
> +
> + return MOD;
> +}
> +
> +/**
> + * file_hash_list__remove: Remove a file entry from the file_hash table
> + * @file_hash: file_hash_table
> + * @target: file name
> + *
> + * Removes the entries from file_hash table corresponding to @target.
> + * Gets the key from @target. Also frees up the SDT events for that
> + * file.
> + */
> +static int file_hash_list__remove(struct hash_list *file_hash,
> + const char *target)
> +{
> + struct file_sdt_ent *fse, *tmp1;
> + struct list_head *sdt_head, *ent_head;
> + struct sdt_note *sdt_ptr, *tmp2;
> +
> + char *res_path;
> + int key, nr_del = 0;
> +
> + key = get_hash_key(target);
> + ent_head = &file_hash->ent[key].list;
> +
> + res_path = realpath(target, NULL);
> + if (!res_path)
> + return -ENOMEM;
> +
> + if (list_empty(ent_head))
> + return 0;
> +
> + /* Got the file hash entry */
> + list_for_each_entry_safe(fse, tmp1, ent_head, file_list) {
> + sdt_head = &fse->sdt_list;
> + if (strcmp(res_path, fse->name))
> + continue;
> +
> + /* Got the file list entry, now start removing */
> + list_for_each_entry_safe(sdt_ptr, tmp2, sdt_head, note_list) {
> + list_del(&sdt_ptr->note_list);
> + free(sdt_ptr->name);
> + free(sdt_ptr->provider);
> + free(sdt_ptr);
> + nr_del++;
> + }
You can use cleanup_sdt_note_list() here. If you need to count nr_del, modify
cleanup_sdt_note_list() to return the number.
> + list_del(&fse->file_list);
> + list_del(&fse->sdt_list);
> + free(fse);
> + }
> +
> + return nr_del;
> +}
> +/**
> + * file_hash_list__entry_exists: Checks if a file is already present
> + * @file_hash: file_hash table
> + * @file: file name and build id to check
> + *
> + * Obtains the key from @file->name, fetches the correct entry,
> + * and goes through the chain to find out the correct file list entry.
> + * Compares the build id, if they match, return true, else, false.
> + */
> +static bool file_hash_list__entry_exists(struct hash_list *file_hash,
> + struct file_info *file)
> +{
> + struct file_sdt_ent *fse;
> + struct list_head *ent_head;
> + int key;
> +
> + key = get_hash_key(file->name);
> + ent_head = &file_hash->ent[key].list;
> + if (list_empty(ent_head))
> + return false;
> +
> + list_for_each_entry(fse, ent_head, file_list) {
> + if (!strcmp(file->name, fse->name)) {
> + if (!strcmp(file->sbuild_id, fse->sbuild_id))
> + return true;
> + }
> + }
> +
> + return false;
> +}
> +
> +/**
> + * copy_delim: copy till a character
> + * @src: source string
> + * @target: dest string
> + * @delim: till this character
> + * @len: length of @target
> + * @end: end of @src
> + *
> + * Returns the number of chars copied.
> + * NOTE: We need @end as @src may or may not be terminated by NULL
> + */
> +static int copy_delim(char *src, char *target, char delim, size_t len,
> + char *end)
> +{
> + int i;
> +
> + memset(target, '\0', len);
I'm not sure why this is needed.
> + for (i = 0; (src[i] != delim) && !(src + i > end) ; i++)
> + target[i] = src[i];
> +
> + return i + 1;
> +}
Anyway, this may be replaced with strchr(3) or strtok_r(3) and strncpy(3).
> +
> +/**
> + * sdt_note__read: Parse SDT note info
> + * @ptr: raw data
> + * @sdt_list: empty list
> + * @end: end of the raw data
> + *
> + * Parse @ptr to find out SDT note name, provider, location and semaphore.
> + * All these data are separated by DELIM.
> + */
> +static void sdt_note__read(char **ptr, struct list_head *sdt_list, char *end)
> +{
> + struct sdt_note *sn;
> + char addr[MAX_ADDR];
> + int len = 0;
> +
> + while (1) {
Hmm, shouldn't we check the end of the sdt note?
> + sn = (struct sdt_note *)malloc(sizeof(struct sdt_note));
> + if (!sn)
> + return;
> + INIT_LIST_HEAD(&sn->note_list);
> + sn->name = (char *)malloc(PATH_MAX);
> + if (!sn->name)
> + return;
> + sn->provider = (char *)malloc(PATH_MAX);
> + if (!sn->provider)
> + return;
> + /* Extract the provider name */
> + len = copy_delim(*ptr, sn->provider, DELIM, PATH_MAX, end);
> + *ptr += len;
> +
> + /* Extract the note name */
> + len = copy_delim(*ptr, sn->name, DELIM, PATH_MAX, end);
> + *ptr += len;
> +
> + /* Extract the note's location */
> + len = copy_delim(*ptr, addr , DELIM, MAX_ADDR, end);
> + *ptr += len;
> + sscanf(addr, "%lx", &sn->addr.a64[0]);
> +
> + /* Extract the sem location */
> + len = copy_delim(*ptr, addr , DELIM, MAX_ADDR, end);
> + *ptr += len;
> + sscanf(addr, "%lx", &sn->addr.a64[2]);
> + list_add(&sn->note_list, sdt_list);
> +
> + /* If the entries for this file are finished */
> + if (**ptr == DELIM)
> + break;
> + }
> +}
> +
> +/**
> + * file_hash_list__populate: Fill up the file hash table
> + * @file_hash: empty file hash table
> + * @data: raw cache data
> + * @size: size of data
> + *
> + * Find out the end of data with help of @size. Start parsing @data.
> + * In the outer loop, it reads the 'key' delimited by "::-". In the inner
> + * loop, it reads the file name, build id and calls sdt_note__read() to
> + * read the SDT notes. Multiple entries for the same key are delimited
> + * by "::". Then, it assigns the file name, build id and SDT notes to the
> + * list entry corresponding to 'key'.
> + */
> +static void file_hash_list__populate(struct hash_list *file_hash, char *data,
> + off_t size)
> +{
> + struct list_head *ent_head;
> + struct file_sdt_ent *fse;
> + char *end, tmp[PATH_MAX], *ptr;
> + int key, len = 0;
> +
> + end = data + size - 1;
> + ptr = data;
> + if (ptr == end)
> + return;
> + do {
Why don't you use while(ptr < end) {} here ?
> + /* Obtain the key */
> + len = copy_delim(ptr, tmp, DELIM, PATH_MAX, end);
> + ptr += len;
> + key = atoi(tmp);
> + /* Obtain the file_hash list entry */
> + ent_head = &file_hash->ent[key].list;
> + while (1) {
> + fse = (struct file_sdt_ent *)
> + malloc(sizeof(struct file_sdt_ent));
> + if (!fse)
> + return;
> + INIT_LIST_HEAD(&fse->file_list);
> + INIT_LIST_HEAD(&fse->sdt_list);
> + /* Obtain the file name */
> + len = copy_delim(ptr, fse->name, DELIM,
> + sizeof(fse->name), end);
> + ptr += len;
> + /* Obtain the build id */
> + len = copy_delim(ptr, fse->sbuild_id, DELIM,
> + sizeof(fse->sbuild_id), end);
> + ptr += len;
> + sdt_note__read(&ptr, &fse->sdt_list, end);
> +
> + list_add(&fse->file_list, ent_head);
> +
> + /* Check for another file entry */
> + if ((*ptr++ == DELIM) && (*ptr == '-'))
> + break;
> + }
> + if (ptr == end)
> + break;
> + else
> + ptr++;
> +
> + } while (1);
> +}
> +
> +/**
> + * file_hash_list__init: Initializes the file hash list
> + * @file_hash: empty file_hash
> + *
> + * Opens the cache file, reads the data into 'data' and calls
> + * file_hash_list__populate() to populate the above hash list.
> + */
> +static void file_hash_list__init(struct hash_list *file_hash)
This should return an error code, since there are lots of error paths.
> +{
> + struct stat sb;
> + char *data;
> + int fd, i, ret;
> +
> + for (i = 0; i < HASH_TABLE_SIZE; i++)
> + INIT_LIST_HEAD(&file_hash->ent[i].list);
> +
> + fd = open(SDT_CACHE_DIR SDT_FILE_CACHE, O_RDONLY);
> + if (fd == -1)
> + return;
> +
> + ret = fstat(fd, &sb);
> + if (ret == -1) {
> + pr_err("fstat : error\n");
> + return;
> + }
> +
> + if (!S_ISREG(sb.st_mode)) {
> + pr_err("%s is not a regular file\n", SDT_CACHE_DIR
> + SDT_FILE_CACHE);
> + return;
> + }
> + /* Is size of the cache zero ?*/
> + if (!sb.st_size)
> + return;
> + /* Read the data */
> + data = mmap(0, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);
> + if (data == MAP_FAILED) {
> + pr_err("Error in mmap\n");
> + return;
> + }
> +
> + ret = madvise(data, sb.st_size, MADV_SEQUENTIAL);
> + if (ret == -1)
> + pr_debug("Error in madvise\n");
At first step, you don't need to take care of the speed.
> + ret = close(fd);
> + if (ret == -1) {
> + pr_err("Error in close\n");
> + return;
> + }
> +
> + /* Populate the hash list */
> + file_hash_list__populate(file_hash, data, sb.st_size);
> + ret = munmap(data, sb.st_size);
> + if (ret == -1)
> + pr_err("Error in munmap\n");
> +}
> +
> +/**
> + * file_hash_list__cleanup: Free up all the space for file_hash list
> + * @file_hash: file_hash table
> + */
> +static void file_hash_list__cleanup(struct hash_list *file_hash)
> +{
> + struct file_sdt_ent *file_pos, *tmp;
> + struct list_head *ent_head, *sdt_head;
> + int i;
> +
> + /* Go through all the entries */
> + for (i = 0; i < HASH_TABLE_SIZE; i++) {
> + ent_head = &file_hash->ent[i].list;
> + if (list_empty(ent_head))
> + continue;
> +
> + list_for_each_entry_safe(file_pos, tmp, ent_head, file_list) {
> + sdt_head = &file_pos->sdt_list;
> + /* Cleanup the corresponding SDT notes' list */
> + cleanup_sdt_note_list(sdt_head);
> + list_del(&file_pos->file_list);
> + list_del(&file_pos->sdt_list);
> + free(file_pos);
> + }
> + }
> +}
> +
> +/**
> + * add_to_hash_list: add an entry to file_hash_list
> + * @file_hash: file hash table
> + * @target: file name
> + *
> + * Does a sanity check for the @target, finds out its build id,
> + * checks if @target is already present in file hash list. If not present,
> + * delete any stale entries with this file name (i.e., entries matching this
> + * file name but having older build ids). And then, adds the file entry to
> + * file hash list and also updates the SDT events in the event hash list.
> + */
> +static int add_to_hash_list(struct hash_list *file_hash, const char *target)
> +{
> + struct file_info *file;
> + int ret = 0;
> + u8 build_id[BUILD_ID_SIZE];
> +
> + LIST_HEAD(sdt_notes);
> +
> + file = (struct file_info *)malloc(sizeof(struct file_info));
> + if (!file)
> + return -ENOMEM;
> +
> + file->name = realpath(target, NULL);
> + if (!file->name) {
> + ret = -EBADF;
> + pr_err("%s: Bad file name!\n", target);
> + goto out;
> + }
> +
> + symbol__elf_init();
> + if (filename__read_build_id(file->name, &build_id,
> + sizeof(build_id)) < 0) {
> + pr_err("Couldn't read build-id in %s\n", file->name);
> + ret = -EBADF;
> + sdt_err(ret, file->name);
> + goto out;
> + }
> + build_id__sprintf(build_id, sizeof(build_id), file->sbuild_id);
> + /* File entry already exists ?*/
> + if (file_hash_list__entry_exists(file_hash, file)) {
> + pr_err("Error: SDT events for %s already exist!",
> + file->name);
> + ret = NO_MOD;
NO_MOD is too generic. I'd like to suggest that this returns the number of
modified(added) entries.
> + goto out;
> + }
> +
> + /*
> + * This will also remove any stale entries (if any) from the event hash.
> + * Stale entries will have the same file name but older build ids.
> + */
> + file_hash_list__remove(file_hash, file->name);
> + ret = get_sdt_note_list(&sdt_notes, file->name);
> + if (!ret) {
> + /* Add the entry to file hash list */
> + ret = file_hash_list__add(&sdt_notes, file, file_hash);
> + } else {
> + sdt_err(ret, target);
> + }
> +
> +out:
> + free(file->name);
> + free(file);
> + return ret;
> +}
> +
> +/**
> + * file_hash_list__flush: Flush the file_hash list to cache
> + * @file_hash: file_hash list
> + * @fcache: opened SDT events cache
> + *
> + * Iterate through all the entries of @file_hash and flush them
> + * onto fcache.
> + * The complete file hash list is flushed into the cache. First
> + * write the key for non-empty entry and then file entries for that
> + * key, and then the SDT notes. The delimiter used is ':'.
> + */
> +static void file_hash_list__flush(struct hash_list *file_hash,
> + FILE *fcache)
> +{
> + struct file_sdt_ent *file_pos;
> + struct list_head *ent_head, *sdt_head;
> + struct sdt_note *sdt_ptr;
> + int i;
> +
> + /* Go through all entries */
> + for (i = 0; i < HASH_TABLE_SIZE; i++) {
> + /* Obtain the list head */
> + ent_head = &file_hash->ent[i].list;
> + /* Empty ? */
> + if (list_empty(ent_head))
> + continue;
> + /* ':' are used here as delimiters */
> + fprintf(fcache, "%d:", i);
> + list_for_each_entry(file_pos, ent_head, file_list) {
> + fprintf(fcache, "%s:", file_pos->name);
> + fprintf(fcache, "%s:", file_pos->sbuild_id);
> + sdt_head = &file_pos->sdt_list;
> + list_for_each_entry(sdt_ptr, sdt_head, note_list) {
> + fprintf(fcache, "%s:%s:%lx:%lx:",
> + sdt_ptr->provider, sdt_ptr->name,
> + sdt_ptr->addr.a64[0],
> + sdt_ptr->addr.a64[2]);
> + }
> + fprintf(fcache, ":");
Hmm, this format is horrible. Please use more sscanf-readable format, so that
we can simplify the reader-side code. e.g.
<number>:\n
<file>:<buildid>\n
<provider>:<name>:<addr>:<sem>\n
:\n
<number>:\n
...
Then, you can use fscanf(), or a combination of fgets() and sscanf().
We don't need to care about the loading speed at this point.
> + }
> + /* '-' marks the end of entries for that key */
> + fprintf(fcache, "-");
> + }
> +
> +}
> +
> +/**
> + * flush_hash_list_to_cache: Flush everything from file_hash to disk
> + * @file_hash: file_hash list
> + *
> + * Opens a cache and calls file_hash_list__flush() to dump everything
> + * on to the cache.
> + */
> +static void flush_hash_list_to_cache(struct hash_list *file_hash)
> +{
> + FILE *cache;
> + int ret;
> + struct stat buf;
> +
> + ret = stat(SDT_CACHE_DIR, &buf);
> + if (ret) {
> + ret = mkdir(SDT_CACHE_DIR, buf.st_mode);
> + if (ret) {
> + pr_err("%s : %s\n", SDT_CACHE_DIR, strerror(errno));
> + return;
> + }
> + }
> +
> + cache = fopen(SDT_CACHE_DIR SDT_FILE_CACHE, "w");
> + if (!cache) {
> + pr_err("Error in creating %s file!\n",
> + SDT_CACHE_DIR SDT_FILE_CACHE);
> + return;
> + }
> +
> + file_hash_list__flush(file_hash, cache);
> + fclose(cache);
> +}
> +
> +/**
> + * add_sdt_events: Add SDT events
> + * @arg: filename
> + *
> + * Initializes a hash table 'file_hash', calls add_to_hash_list() to add SDT
> + * events of @arg to the cache and then cleans them up.
> + * 'file_hash' list is a hash table which maintains all the information
> + * related to the files with the SDT events in them. The file name serves as the
> + * key to this hash list. Each entry of the file_hash table is a list head
> + * which contains a chain of 'file_list' entries. Each 'file_list' entry contains
> + * the list of SDT events found in that file. This hash serves as a mapping
> + * from file name to the SDT events. 'file_hash' is used to add/del SDT events
> + * to the SDT cache.
> + */
> +int add_sdt_events(const char *arg)
> +{
> + struct hash_list file_hash;
> + int ret;
> +
> + if (!arg) {
> + pr_err("Error : File Name must be specified with \"--add\""
> + "option!\n"
> + "Usage :\n perf sdt-cache --add <file-name>\n");
> + return -1;
> + }
> + /* Initialize the file hash_list */
> + file_hash_list__init(&file_hash);
> +
> + /* Try to add the events to the file hash_list */
> + ret = add_to_hash_list(&file_hash, arg);
> + switch (ret) {
> + case MOD:
> + /* file hash table is dirty, flush it */
> + flush_hash_list_to_cache(&file_hash);
> + case NO_MOD:
> + /* file hash isn't dirty, do not flush */
> + file_hash_list__cleanup(&file_hash);
> + ret = 0;
> + break;
Again, MOD and NO_MOD is too general.
> + default:
> + file_hash_list__cleanup(&file_hash);
> + }
> + return ret;
> +}
> diff --git a/tools/perf/util/sdt.h b/tools/perf/util/sdt.h
> new file mode 100644
> index 0000000..4ed27d7
> --- /dev/null
> +++ b/tools/perf/util/sdt.h
> @@ -0,0 +1,30 @@
> +#include "build-id.h"
> +
> +#define HASH_TABLE_SIZE 2063
> +#define SDT_CACHE_DIR "/var/cache/perf/"
> +#define SDT_FILE_CACHE "perf-sdt-file.cache"
> +#define SDT_EVENT_CACHE "perf-sdt-event.cache"
Hmm, this should be treated as same as buildid_dir. Please see util/config.c.
Thank you,
> +
> +#define DELIM ':'
> +#define MAX_ADDR 17
> +
> +#define MOD 1
> +#define NO_MOD 2
> +
> +struct file_sdt_ent {
> + char name[PATH_MAX]; /* file name */
> + char sbuild_id[BUILD_ID_SIZE * 2 + 1]; /* Build id of the file */
> + struct list_head file_list;
> + struct list_head sdt_list; /* SDT notes in this file */
> +
> +};
> +
> +/* hash table entry */
> +struct hash_ent {
> + struct list_head list;
> +};
> +
> +/* Hash table struct */
> +struct hash_list {
> + struct hash_ent ent[HASH_TABLE_SIZE];
> +};
>
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: [email protected]
On 10/03/2014 06:17 PM, Masami Hiramatsu wrote:
> (2014/10/01 0:32), Hemant Kumar wrote:
>> This patch adds a new sub-command to perf : sdt-cache.
> When I ran perf without option, sdt-cache did not appear. You should update
> command-list.txt and add Documentation/perf-sdt-cache.txt, so that sdt-cache is
> shown (Note that perf build automatically extracts NAME line and embeds it as a
> help message). Maybe commit ef12a141 is good to refer :)
Will add that.
>> sdt-cache command can be used to add, remove and dump SDT events.
>> This patch adds support to only "add" the SDT events. The rest of the
>> patches add support to rest of them.
> You don't need to describe dump and remove in this patch. How about below?
>
> perf-sdt-cache command manages SDT events in applications. This adds
> "perf sdt-cache --add <file>" to add SDT events in given file to local
> cache.
>
Ok.
>> When user invokes "perf sdt-cache add <file-name>", two hash tables are
>> created: file_hash list and event_hash list. A typical entry in a file_hash
>> table looks like:
>> file hash file_sdt_ent file_sdt_ent
>> |---------| --------------- -------------
>> | list ==|===|=>file_list =|===|=>file_list=|==..
>> key = 644 =>| | | sbuild_id | | sbuild_id |
>> |---------| | name | | name |
>> | | | sdt_list | | sdt_list |
>> key = 645 =>| list | | || | | || |
>> |---------| --------------- --------------
>> || || || Connected to SDT notes
>> ---------------
>> | note_list |
>> sdt_note| name |
>> | provider |
>> -----||--------
>> connected to other SDT notes
> Hmm, why don't you use hlist for file_hash.list?
Will use hlist.
>>
>> Each entry of the file_hash table is a list which connects to file_list in
>> file_sdt_ent. file_sdt_ent is allocated per file whenever a file is mapped
>> to file_hash list. File name serves as the key to this hash table.
>> If a file is added to this hash list, a file_sdt_ent is allocated and a
>> list of SDT events in that file is created and assigned to sdt_list of
>> file_sdt_ent.
>>
>> Example usage :
>> # ./perf sdt-cache --add /home/user_app
>>
>> 4 events added for /home/user_app!
>>
>> # ./perf sdt-cache --add /lib64/libc.so.6
>>
>> 8 events added for /usr/lib64/libc-2.16.so!
> IMO, when succeeding to add events, it may not need the last "!", since
> it is eye-catching too much (as like as we get an error).
Ok. Will remove '!'.
>
> [...]
>> diff --git a/tools/perf/util/sdt.c b/tools/perf/util/sdt.c
>> new file mode 100644
>> index 0000000..0b56210
>> --- /dev/null
>> +++ b/tools/perf/util/sdt.c
>> @@ -0,0 +1,665 @@
>> +/*
>> + * util/sdt.c
>> + * This contains the relevant functions needed to find the SDT events
>> + * in a binary and adding them to a cache.
>> + *
>> + * TODOS:
>> + * - Listing SDT events in most of the binaries present in the system.
>> + * - Looking into directories provided by the user for binaries with SDTs,
>> + * etc.
>> + * - Support SDT event arguments.
>> + * - Support SDT event semaphores.
>> + */
>> +
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <errno.h>
>> +#include <string.h>
>> +#include <sys/types.h>
>> +#include <sys/stat.h>
>> +#include <unistd.h>
>> +#include <limits.h>
>> +#include <sys/mman.h>
>> +#include <fcntl.h>
>> +
>> +#include "parse-events.h"
>> +#include "probe-event.h"
>> +#include "linux/list.h"
>> +#include "symbol.h"
>> +#include "build-id.h"
>> +
>> +struct file_info {
>> + char *name; /* File name */
>> + char sbuild_id[BUILD_ID_SIZE * 2 + 1]; /* Build id of the file */
>> +};
>> +
>> +/**
>> + * get_hash_key: calculates the key to hash tables
>> + * @str: input string
>> + *
>> + * adds the ascii values for all the chars in @str, multiplies with a prime
>> + * and finds the modulo with HASH_TABLE_SIZE.
>> + *
>> + * Return : An integer key
>> + */
>> +static unsigned get_hash_key(const char *str)
>> +{
>> + unsigned value = 0, key;
>> + unsigned c;
>> +
>> + for (c = 0; str[c] != '\0'; c++)
>> + value += str[c];
>> +
>> + key = (value * 37) % HASH_TABLE_SIZE;
> 37 seems to a magic number :) how about defining it as HASH_PRIME_BASE?
Yeah. will make it a #define.
>> +
>> + return key;
>> +}
>> +
>> +/**
>> + * sdt_err: print SDT related error
>> + * @val: error code
>> + * @target: input file
>> + *
>> + * Display error corresponding to @val for file @target
>> + */
>> +static int sdt_err(int val, const char *target)
>> +{
>> + switch (-val) {
>> + case 0:
>> + break;
>> + case ENOENT:
>> + /* Absence of SDT markers */
>> + pr_err("%s: No SDT events found\n", target);
>> + break;
>> + case EBADF:
>> + pr_err("%s: Bad file name\n", target);
>> + break;
>> + default:
>> + pr_err("%s\n", strerror(val));
>> + }
>> +
>> + return val;
>> +}
>> +
>> +/**
>> + * cleanup_sdt_note_list : free the sdt notes' list
>> + * @sdt_notes: sdt notes' list
>> + *
>> + * Free up the SDT notes in @sdt_notes.
>> + */
>> +static void cleanup_sdt_note_list(struct list_head *sdt_notes)
>> +{
>> + struct sdt_note *tmp, *pos;
>> +
>> + if (list_empty(sdt_notes))
>> + return;
>> +
>> + list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
>> + list_del(&pos->note_list);
>> + free(pos->name);
>> + free(pos->provider);
>> + free(pos);
>> + }
>> +}
> Hmm, since the list is created in tools/perf/util/symbol-elf.c, it is better
> to be defined in the same file, and same patch(1/1).
Ok. Moving into patch1 and inside util/symbol-elf.c does make sense.
>> +
>> +/**
>> + * file_list_entry__init: Initialize a file_list_entry
>> + * @fse: file_list_entry
>> + * @file: file information
>> + *
>> + * Initializes @fse with the build id of a @file.
>> + */
>> +static void file_list_entry__init(struct file_sdt_ent *fse,
>> + struct file_info *file)
>> +{
>> + strcpy(fse->sbuild_id, file->sbuild_id);
>> + INIT_LIST_HEAD(&fse->file_list);
>> + INIT_LIST_HEAD(&fse->sdt_list);
>> +}
>> +
>> +/**
>> + * sdt_events__get_count: Counts the number of sdt events
>> + * @start: list_head to sdt_notes list
>> + *
>> + * Returns the number of SDT notes in a list
>> + */
>> +static int sdt_events__get_count(struct list_head *start)
>> +{
>> + struct sdt_note *sdt_ptr;
>> + int count = 0;
>> +
>> + list_for_each_entry(sdt_ptr, start, note_list) {
>> + count++;
>> + }
>> + return count;
>> +}
> This should be also in symbol-elf.c or symbol.h. Moreover, since there is no sdt_events
> data structure, the function name looks a bit odd.
Will rename it to sdt_note_list__get_count() and will move it to symbol.h.
>
>> +
>> +/**
>> + * file_hash_list__add: add an entry to file_hash_list
>> + * @sdt_notes: list of sdt_notes
>> + * @file: file name and build id
>> + * @file_hash: hash table for file and sdt notes
>> + *
>> + * Get the key corresponding to @file->name. Fetch the entry
>> + * for that key. Build a file_list_entry fse, assign the SDT notes
>> + * to it and then assign fse to the fetched entry into the hash.
>> + */
>> +static int file_hash_list__add(struct list_head *sdt_notes,
>> + struct file_info *file,
>> + struct hash_list *file_hash)
>> +{
>> + struct file_sdt_ent *fse;
>> + struct list_head *ent_head;
>> + int key, nr_evs;
>> +
>> + key = get_hash_key(file->name);
>> + ent_head = &file_hash->ent[key].list;
>> +
>> + /* Initialize the file entry */
>> + fse = (struct file_sdt_ent *)malloc(sizeof(struct file_sdt_ent));
>> + if (!fse)
>> + return -ENOMEM;
>> + file_list_entry__init(fse, file);
>> + nr_evs = sdt_events__get_count(sdt_notes);
>> + list_splice(sdt_notes, &fse->sdt_list);
>> +
>> + printf("%d events added for %s\n", nr_evs, file->name);
>> + strcpy(fse->name, file->name);
>> +
>> + /* Add the file to the file hash entry */
>> + list_add(&fse->file_list, ent_head);
>> +
>> + return MOD;
>> +}
>> +
>> +/**
>> + * file_hash_list__remove: Remove a file entry from the file_hash table
>> + * @file_hash: file_hash_table
>> + * @target: file name
>> + *
>> + * Removes the entries from file_hash table corresponding to @target.
>> + * Gets the key from @target. Also frees up the SDT events for that
>> + * file.
>> + */
>> +static int file_hash_list__remove(struct hash_list *file_hash,
>> + const char *target)
>> +{
>> + struct file_sdt_ent *fse, *tmp1;
>> + struct list_head *sdt_head, *ent_head;
>> + struct sdt_note *sdt_ptr, *tmp2;
>> +
>> + char *res_path;
>> + int key, nr_del = 0;
>> +
>> + key = get_hash_key(target);
>> + ent_head = &file_hash->ent[key].list;
>> +
>> + res_path = realpath(target, NULL);
>> + if (!res_path)
>> + return -ENOMEM;
>> +
>> + if (list_empty(ent_head))
>> + return 0;
>> +
>> + /* Got the file hash entry */
>> + list_for_each_entry_safe(fse, tmp1, ent_head, file_list) {
>> + sdt_head = &fse->sdt_list;
>> + if (strcmp(res_path, fse->name))
>> + continue;
>> +
>> + /* Got the file list entry, now start removing */
>> + list_for_each_entry_safe(sdt_ptr, tmp2, sdt_head, note_list) {
>> + list_del(&sdt_ptr->note_list);
>> + free(sdt_ptr->name);
>> + free(sdt_ptr->provider);
>> + free(sdt_ptr);
>> + nr_del++;
>> + }
> You can use cleanup_sdt_note_list() here. If you need to count nr_del, modify
> cleanup_sdt_note_list() to return the number.
Oops, yeah I can use cleanup_sdt_note_list() here.
>> + list_del(&fse->file_list);
>> + list_del(&fse->sdt_list);
>> + free(fse);
>> + }
>> +
>> + return nr_del;
>> +}
>> +/**
>> + * file_hash_list__entry_exists: Checks if a file is already present
>> + * @file_hash: file_hash table
>> + * @file: file name and build id to check
>> + *
>> + * Obtains the key from @file->name, fetches the correct entry,
>> + * and goes through the chain to find out the correct file list entry.
>> + * Compares the build id, if they match, return true, else, false.
>> + */
>> +static bool file_hash_list__entry_exists(struct hash_list *file_hash,
>> + struct file_info *file)
>> +{
>> + struct file_sdt_ent *fse;
>> + struct list_head *ent_head;
>> + int key;
>> +
>> + key = get_hash_key(file->name);
>> + ent_head = &file_hash->ent[key].list;
>> + if (list_empty(ent_head))
>> + return false;
>> +
>> + list_for_each_entry(fse, ent_head, file_list) {
>> + if (!strcmp(file->name, fse->name)) {
>> + if (!strcmp(file->sbuild_id, fse->sbuild_id))
>> + return true;
>> + }
>> + }
>> +
>> + return false;
>> +}
>> +
>> +/**
>> + * copy_delim: copy till a character
>> + * @src: source string
>> + * @target: dest string
>> + * @delim: till this character
>> + * @len: length of @target
>> + * @end: end of @src
>> + *
>> + * Returns the number of chars copied.
>> + * NOTE: We need @end as @src may or may not be terminated by NULL
>> + */
>> +static int copy_delim(char *src, char *target, char delim, size_t len,
>> + char *end)
>> +{
>> + int i;
>> +
>> + memset(target, '\0', len);
> I'm not sure why this is needed.
>
>> + for (i = 0; (src[i] != delim) && !(src + i > end) ; i++)
>> + target[i] = src[i];
>> +
>> + return i + 1;
>> +}
> Anyway, this may be replaced with strchr(3) or strtok_r(3) and strncpy(3).
Will discard this whole func and use strchr() and strtok_r().
>> +
>> +/**
>> + * sdt_note__read: Parse SDT note info
>> + * @ptr: raw data
>> + * @sdt_list: empty list
>> + * @end: end of the raw data
>> + *
>> + * Parse @ptr to find out SDT note name, provider, location and semaphore.
>> + * All these data are separated by DELIM.
>> + */
>> +static void sdt_note__read(char **ptr, struct list_head *sdt_list, char *end)
>> +{
>> + struct sdt_note *sn;
>> + char addr[MAX_ADDR];
>> + int len = 0;
>> +
>> + while (1) {
> Hmm, shouldn't we check the end of the sdt note?
We are checking this inside the loop with copy_delim() and if (*ptr ==
DELIM), but
I guess its better to put the check in while itself.
>
>> + sn = (struct sdt_note *)malloc(sizeof(struct sdt_note));
>> + if (!sn)
>> + return;
>> + INIT_LIST_HEAD(&sn->note_list);
>> + sn->name = (char *)malloc(PATH_MAX);
>> + if (!sn->name)
>> + return;
>> + sn->provider = (char *)malloc(PATH_MAX);
>> + if (!sn->provider)
>> + return;
>> + /* Extract the provider name */
>> + len = copy_delim(*ptr, sn->provider, DELIM, PATH_MAX, end);
>> + *ptr += len;
>> +
>> + /* Extract the note name */
>> + len = copy_delim(*ptr, sn->name, DELIM, PATH_MAX, end);
>> + *ptr += len;
>> +
>> + /* Extract the note's location */
>> + len = copy_delim(*ptr, addr , DELIM, MAX_ADDR, end);
>> + *ptr += len;
>> + sscanf(addr, "%lx", &sn->addr.a64[0]);
>> +
>> + /* Extract the sem location */
>> + len = copy_delim(*ptr, addr , DELIM, MAX_ADDR, end);
>> + *ptr += len;
>> + sscanf(addr, "%lx", &sn->addr.a64[2]);
>> + list_add(&sn->note_list, sdt_list);
>> +
>> + /* If the entries for this file are finished */
>> + if (**ptr == DELIM)
>> + break;
>> + }
>> +}
>> +
>> +/**
>> + * file_hash_list__populate: Fill up the file hash table
>> + * @file_hash: empty file hash table
>> + * @data: raw cache data
>> + * @size: size of data
>> + *
>> + * Find out the end of data with help of @size. Start parsing @data.
>> + * In the outer loop, it reads the 'key' delimited by "::-". In the inner
>> + * loop, it reads the file name, build id and calls sdt_note__read() to
>> + * read the SDT notes. Multiple entries for the same key are delimited
>> + * by "::". Then, it assigns the file name, build id and SDT notes to the
>> + * list entry corresponding to 'key'.
>> + */
>> +static void file_hash_list__populate(struct hash_list *file_hash, char *data,
>> + off_t size)
>> +{
>> + struct list_head *ent_head;
>> + struct file_sdt_ent *fse;
>> + char *end, tmp[PATH_MAX], *ptr;
>> + int key, len = 0;
>> +
>> + end = data + size - 1;
>> + ptr = data;
>> + if (ptr == end)
>> + return;
>> + do {
> Why don't you use while(ptr < end) {} here ?
Will use that.
>> + /* Obtain the key */
>> + len = copy_delim(ptr, tmp, DELIM, PATH_MAX, end);
>> + ptr += len;
>> + key = atoi(tmp);
>> + /* Obtain the file_hash list entry */
>> + ent_head = &file_hash->ent[key].list;
>> + while (1) {
>> + fse = (struct file_sdt_ent *)
>> + malloc(sizeof(struct file_sdt_ent));
>> + if (!fse)
>> + return;
>> + INIT_LIST_HEAD(&fse->file_list);
>> + INIT_LIST_HEAD(&fse->sdt_list);
>> + /* Obtain the file name */
>> + len = copy_delim(ptr, fse->name, DELIM,
>> + sizeof(fse->name), end);
>> + ptr += len;
>> + /* Obtain the build id */
>> + len = copy_delim(ptr, fse->sbuild_id, DELIM,
>> + sizeof(fse->sbuild_id), end);
>> + ptr += len;
>> + sdt_note__read(&ptr, &fse->sdt_list, end);
>> +
>> + list_add(&fse->file_list, ent_head);
>> +
>> + /* Check for another file entry */
>> + if ((*ptr++ == DELIM) && (*ptr == '-'))
>> + break;
>> + }
>> + if (ptr == end)
>> + break;
>> + else
>> + ptr++;
>> +
>> + } while (1);
>> +}
>> +
>> +/**
>> + * file_hash_list__init: Initializes the file hash list
>> + * @file_hash: empty file_hash
>> + *
>> + * Opens the cache file, reads the data into 'data' and calls
>> + * file_hash_list__populate() to populate the above hash list.
>> + */
>> +static void file_hash_list__init(struct hash_list *file_hash)
> This should return an error code, since there are lots of error paths.
Yeah, will change this.
>> +{
>> + struct stat sb;
>> + char *data;
>> + int fd, i, ret;
>> +
>> + for (i = 0; i < HASH_TABLE_SIZE; i++)
>> + INIT_LIST_HEAD(&file_hash->ent[i].list);
>> +
>> + fd = open(SDT_CACHE_DIR SDT_FILE_CACHE, O_RDONLY);
>> + if (fd == -1)
>> + return;
>> +
>> + ret = fstat(fd, &sb);
>> + if (ret == -1) {
>> + pr_err("fstat : error\n");
>> + return;
>> + }
>> +
>> + if (!S_ISREG(sb.st_mode)) {
>> + pr_err("%s is not a regular file\n", SDT_CACHE_DIR
>> + SDT_FILE_CACHE);
>> + return;
>> + }
>> + /* Is size of the cache zero ?*/
>> + if (!sb.st_size)
>> + return;
>> + /* Read the data */
>> + data = mmap(0, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);
>> + if (data == MAP_FAILED) {
>> + pr_err("Error in mmap\n");
>> + return;
>> + }
>> +
>> + ret = madvise(data, sb.st_size, MADV_SEQUENTIAL);
>> + if (ret == -1)
>> + pr_debug("Error in madvise\n");
> At first step, you don't need to take care of the speed.
Will move this to where I parse the data.
>> + ret = close(fd);
>> + if (ret == -1) {
>> + pr_err("Error in close\n");
>> + return;
>> + }
>> +
>> + /* Populate the hash list */
>> + file_hash_list__populate(file_hash, data, sb.st_size);
>> + ret = munmap(data, sb.st_size);
>> + if (ret == -1)
>> + pr_err("Error in munmap\n");
>> +}
>> +
>> +/**
>> + * file_hash_list__cleanup: Free up all the space for file_hash list
>> + * @file_hash: file_hash table
>> + */
>> +static void file_hash_list__cleanup(struct hash_list *file_hash)
>> +{
>> + struct file_sdt_ent *file_pos, *tmp;
>> + struct list_head *ent_head, *sdt_head;
>> + int i;
>> +
>> + /* Go through all the entries */
>> + for (i = 0; i < HASH_TABLE_SIZE; i++) {
>> + ent_head = &file_hash->ent[i].list;
>> + if (list_empty(ent_head))
>> + continue;
>> +
>> + list_for_each_entry_safe(file_pos, tmp, ent_head, file_list) {
>> + sdt_head = &file_pos->sdt_list;
>> + /* Cleanup the corresponding SDT notes' list */
>> + cleanup_sdt_note_list(sdt_head);
>> + list_del(&file_pos->file_list);
>> + list_del(&file_pos->sdt_list);
>> + free(file_pos);
>> + }
>> + }
>> +}
>> +
>> +/**
>> + * add_to_hash_list: add an entry to file_hash_list
>> + * @file_hash: file hash table
>> + * @target: file name
>> + *
>> + * Does a sanity check for the @target, finds out its build id,
>> + * checks if @target is already present in file hash list. If not present,
>> + * delete any stale entries with this file name (i.e., entries matching this
>> + * file name but having older build ids). And then, adds the file entry to
>> + * file hash list and also updates the SDT events in the event hash list.
>> + */
>> +static int add_to_hash_list(struct hash_list *file_hash, const char *target)
>> +{
>> + struct file_info *file;
>> + int ret = 0;
>> + u8 build_id[BUILD_ID_SIZE];
>> +
>> + LIST_HEAD(sdt_notes);
>> +
>> + file = (struct file_info *)malloc(sizeof(struct file_info));
>> + if (!file)
>> + return -ENOMEM;
>> +
>> + file->name = realpath(target, NULL);
>> + if (!file->name) {
>> + ret = -EBADF;
>> + pr_err("%s: Bad file name!\n", target);
>> + goto out;
>> + }
>> +
>> + symbol__elf_init();
>> + if (filename__read_build_id(file->name, &build_id,
>> + sizeof(build_id)) < 0) {
>> + pr_err("Couldn't read build-id in %s\n", file->name);
>> + ret = -EBADF;
>> + sdt_err(ret, file->name);
>> + goto out;
>> + }
>> + build_id__sprintf(build_id, sizeof(build_id), file->sbuild_id);
>> + /* File entry already exists ?*/
>> + if (file_hash_list__entry_exists(file_hash, file)) {
>> + pr_err("Error: SDT events for %s already exist!",
>> + file->name);
>> + ret = NO_MOD;
> NO_MOD is too generic. I'd like to suggest that this returns the number of
> modified(added) entries.
Ok. Will modify this to return the no. of entries added.
>> + goto out;
>> + }
>> +
>> + /*
>> + * This will also remove any stale entries (if any) from the event hash.
>> + * Stale entries will have the same file name but older build ids.
>> + */
>> + file_hash_list__remove(file_hash, file->name);
>> + ret = get_sdt_note_list(&sdt_notes, file->name);
>> + if (!ret) {
>> + /* Add the entry to file hash list */
>> + ret = file_hash_list__add(&sdt_notes, file, file_hash);
>> + } else {
>> + sdt_err(ret, target);
>> + }
>> +
>> +out:
>> + free(file->name);
>> + free(file);
>> + return ret;
>> +}
>> +
>> +/**
>> + * file_hash_list__flush: Flush the file_hash list to cache
>> + * @file_hash: file_hash list
>> + * @fcache: opened SDT events cache
>> + *
>> + * Iterate through all the entries of @file_hash and flush them
>> + * onto fcache.
>> + * The complete file hash list is flushed into the cache. First
>> + * write the key for non-empty entry and then file entries for that
>> + * key, and then the SDT notes. The delimiter used is ':'.
>> + */
>> +static void file_hash_list__flush(struct hash_list *file_hash,
>> + FILE *fcache)
>> +{
>> + struct file_sdt_ent *file_pos;
>> + struct list_head *ent_head, *sdt_head;
>> + struct sdt_note *sdt_ptr;
>> + int i;
>> +
>> + /* Go through all entries */
>> + for (i = 0; i < HASH_TABLE_SIZE; i++) {
>> + /* Obtain the list head */
>> + ent_head = &file_hash->ent[i].list;
>> + /* Empty ? */
>> + if (list_empty(ent_head))
>> + continue;
>> + /* ':' are used here as delimiters */
>> + fprintf(fcache, "%d:", i);
>> + list_for_each_entry(file_pos, ent_head, file_list) {
>> + fprintf(fcache, "%s:", file_pos->name);
>> + fprintf(fcache, "%s:", file_pos->sbuild_id);
>> + sdt_head = &file_pos->sdt_list;
>> + list_for_each_entry(sdt_ptr, sdt_head, note_list) {
>> + fprintf(fcache, "%s:%s:%lx:%lx:",
>> + sdt_ptr->provider, sdt_ptr->name,
>> + sdt_ptr->addr.a64[0],
>> + sdt_ptr->addr.a64[2]);
>> + }
>> + fprintf(fcache, ":");
> Hmm, this format is horrible. Please use more sscanf-readable format, so that
> we can simplify the reader-side code. e.g.
>
> <number>:\n
> <file>:<buildid>\n
> <provider>:<name>:<addr>:<sem>\n
> :\n
> <number>:\n
> ...
> Then, you can use fscanf(), or a combination of fgets() and sscanf().
> We don't need to care about the loading speed at this point.
>
Hmm, will try this.
>> + }
>> + /* '-' marks the end of entries for that key */
>> + fprintf(fcache, "-");
>> + }
>> +
>> +}
>> +
>> +/**
>> + * flush_hash_list_to_cache: Flush everything from file_hash to disk
>> + * @file_hash: file_hash list
>> + *
>> + * Opens a cache and calls file_hash_list__flush() to dump everything
>> + * on to the cache.
>> + */
>> +static void flush_hash_list_to_cache(struct hash_list *file_hash)
>> +{
>> + FILE *cache;
>> + int ret;
>> + struct stat buf;
>> +
>> + ret = stat(SDT_CACHE_DIR, &buf);
>> + if (ret) {
>> + ret = mkdir(SDT_CACHE_DIR, buf.st_mode);
>> + if (ret) {
>> + pr_err("%s : %s\n", SDT_CACHE_DIR, strerror(errno));
>> + return;
>> + }
>> + }
>> +
>> + cache = fopen(SDT_CACHE_DIR SDT_FILE_CACHE, "w");
>> + if (!cache) {
>> + pr_err("Error in creating %s file!\n",
>> + SDT_CACHE_DIR SDT_FILE_CACHE);
>> + return;
>> + }
>> +
>> + file_hash_list__flush(file_hash, cache);
>> + fclose(cache);
>> +}
>> +
>> +/**
>> + * add_sdt_events: Add SDT events
>> + * @arg: filename
>> + *
>> + * Initializes a hash table 'file_hash', calls add_to_hash_list() to add SDT
>> + * events of @arg to the cache and then cleans them up.
>> + * 'file_hash' list is a hash table which maintains all the information
>> + * related to the files with the SDT events in them. The file name serves as the
>> + * key to this hash list. Each entry of the file_hash table is a list head
>> + * which contains a chain of 'file_list' entries. Each 'file_list' entry contains
>> + * the list of SDT events found in that file. This hash serves as a mapping
>> + * from file name to the SDT events. 'file_hash' is used to add/del SDT events
>> + * to the SDT cache.
>> + */
>> +int add_sdt_events(const char *arg)
>> +{
>> + struct hash_list file_hash;
>> + int ret;
>> +
>> + if (!arg) {
>> + pr_err("Error : File Name must be specified with \"--add\""
>> + "option!\n"
>> + "Usage :\n perf sdt-cache --add <file-name>\n");
>> + return -1;
>> + }
>> + /* Initialize the file hash_list */
>> + file_hash_list__init(&file_hash);
>> +
>> + /* Try to add the events to the file hash_list */
>> + ret = add_to_hash_list(&file_hash, arg);
>> + switch (ret) {
>> + case MOD:
>> + /* file hash table is dirty, flush it */
>> + flush_hash_list_to_cache(&file_hash);
>> + case NO_MOD:
>> + /* file hash isn't dirty, do not flush */
>> + file_hash_list__cleanup(&file_hash);
>> + ret = 0;
>> + break;
> Again, MOD and NO_MOD is too general.
>
>> + default:
>> + file_hash_list__cleanup(&file_hash);
>> + }
>> + return ret;
>> +}
>> diff --git a/tools/perf/util/sdt.h b/tools/perf/util/sdt.h
>> new file mode 100644
>> index 0000000..4ed27d7
>> --- /dev/null
>> +++ b/tools/perf/util/sdt.h
>> @@ -0,0 +1,30 @@
>> +#include "build-id.h"
>> +
>> +#define HASH_TABLE_SIZE 2063
>> +#define SDT_CACHE_DIR "/var/cache/perf/"
>> +#define SDT_FILE_CACHE "perf-sdt-file.cache"
>> +#define SDT_EVENT_CACHE "perf-sdt-event.cache"
> Hmm, this should be treated as same as buildid_dir. Please see util/config.c.
Will look into this. :)
> Thank you,
>
>> +
>> +#define DELIM ':'
>> +#define MAX_ADDR 17
>> +
>> +#define MOD 1
>> +#define NO_MOD 2
>> +
>> +struct file_sdt_ent {
>> + char name[PATH_MAX]; /* file name */
>> + char sbuild_id[BUILD_ID_SIZE * 2 + 1]; /* Build id of the file */
>> + struct list_head file_list;
>> + struct list_head sdt_list; /* SDT notes in this file */
>> +
>> +};
>> +
>> +/* hash table entry */
>> +struct hash_ent {
>> + struct list_head list;
>> +};
>> +
>> +/* Hash table struct */
>> +struct hash_list {
>> + struct hash_ent ent[HASH_TABLE_SIZE];
>> +};
>>
>>
>
Thanks a lot for reviewing the patch.
--
Thanks,
Hemant Kumar