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perf-probe --cache and SDT support

PATCH Superseded Masami Hiramatsu 3 participants 20 messages Jun 24, 2016 – Jul 14, 2016 perf events

v12 of 13 Superseded Latest is v13 →

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#0 lore raw

v12 cover perf-probe --cache and SDT support

Hi,

Here is the 12th version of the patchset for probe-cache and initial SDT support.

Here is the previous v11: https://lkml.org/lkml/2016/6/14/1041

In this version I just rename strlist__for_each to strlist__for_each_entry, and change some patch description.

Thank you,

---

Hemant Kumar (1):
perf/sdt: ELF support for SDT

Masami Hiramatsu (15):
perf probe: Use cache entry if possible
perf probe: Show all cached probes
perf probe: Remove caches when --cache is given
perf probe: Add group name support
perf buildid-cache: Scan and import user SDT events to probe cache perf probe: Accept %sdt and %cached event name
perf-list: Show SDT and pre-cached events
perf-list: Skip SDTs placed in invalid binaries
perf: probe-cache: Add for_each_probe_cache_entry() wrapper perf probe: Allow wildcard for cached events
perf probe: Search SDT/cached event from all probe caches perf probe: Support @BUILDID or @FILE suffix for SDT events perf probe: Support a special SDT probe format
perf build: Add sdt feature detection
perf-test: Add a test case for SDT event

 tools/perf/Documentation/perf-buildid-cache.txt |    3 
 tools/perf/Documentation/perf-probe.txt         |   30 +-
 tools/perf/Makefile.perf                        |    3 
 tools/perf/builtin-list.c                       |    6 
 tools/perf/builtin-probe.c                      |   31 ++
 tools/perf/config/Makefile                      |   10 +
 tools/perf/tests/Build                          |    1 
 tools/perf/tests/builtin-test.c                 |    4 
 tools/perf/tests/make                           |    3 
 tools/perf/tests/sdt.c                          |  115 +++++++
 tools/perf/tests/tests.h                        |    1 
 tools/perf/util/build-id.c                      |  212 +++++++++++++
 tools/perf/util/build-id.h                      |    4 
 tools/perf/util/parse-events.c                  |   82 +++++
 tools/perf/util/parse-events.h                  |    2 
 tools/perf/util/probe-event.c                   |  366 +++++++++++++++++++++--
 tools/perf/util/probe-event.h                   |    1 
 tools/perf/util/probe-file.c                    |  226 +++++++++++++-
 tools/perf/util/probe-file.h                    |   24 +-
 tools/perf/util/symbol-elf.c                    |  252 ++++++++++++++++
 tools/perf/util/symbol.h                        |   22 +
 21 files changed, 1333 insertions(+), 65 deletions(-)
 create mode 100644 tools/perf/tests/sdt.c

--
Masami Hiramatsu

#1 lore raw

PATCH v12 1/16 perf probe: Use cache entry if possible

From: Masami Hiramatsu <[email protected]>

Before analyzing debuginfo, try to find a corresponding entry from probe cache always. This does not depend on --cache, the --cache enables to store/update cache, but looking up the cache is always enabled.

---
Changes in v12:
- Rename strlist__for_each to strlist__for_each_entry.

Changes in v6:
- Remove fallback lookup routine by using function name as cached event name, because it should be done by following patch which supports %cached-event.

---
 tools/perf/util/probe-event.c |   65 ++++++++++++++++++++++++++++++++++++++++-
 tools/perf/util/probe-file.c  |   20 ++++++++++++-
 tools/perf/util/probe-file.h  |    5 +++
 3 files changed, 86 insertions(+), 4 deletions(-)
tools/perf/util/probe-event.c +63 -2
index 55f41d5..47b6b8b 100644
@@ -2474,17 +2474,24 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
 	char buf[64];
 	int ret;
 
+	/* If probe_event or trace_event already have the name, reuse it */
 	if (pev->event)
 		event = pev->event;
-	else
+	else if (tev->event)
+		event = tev->event;
+	else {
+		/* Or generate new one from probe point */
 		if (pev->point.function &&
 			(strncmp(pev->point.function, "0x", 2) != 0) &&
 			!strisglob(pev->point.function))
 			event = pev->point.function;
 		else
 			event = tev->point.realname;
+	}
 	if (pev->group)
 		group = pev->group;
+	else if (tev->group)
+		group = tev->group;
 	else
 		group = PERFPROBE_GROUP;
 
@@ -2531,7 +2538,7 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
 	for (i = 0; i < ntevs; i++) {
 		tev = &tevs[i];
 		/* Skip if the symbol is out of .text or blacklisted */
-		if (!tev->point.symbol)
+		if (!tev->point.symbol && !pev->uprobes)
 			continue;
 
 		/* Set new name for tev (and update namelist) */
@@ -2844,6 +2851,55 @@ errout:
 
 bool __weak arch__prefers_symtab(void) { return false; }
 
+static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
+					      struct probe_trace_event **tevs)
+{
+	struct probe_cache *cache;
+	struct probe_cache_entry *entry;
+	struct probe_trace_event *tev;
+	struct str_node *node;
+	int ret, i;
+
+	cache = probe_cache__new(pev->target);
+	if (!cache)
+		return 0;
+
+	entry = probe_cache__find(cache, pev);
+	if (!entry) {
+		ret = 0;
+		goto out;
+	}
+
+	ret = strlist__nr_entries(entry->tevlist);
+	if (ret > probe_conf.max_probes) {
+		pr_debug("Too many entries matched in the cache of %s\n",
+			 pev->target ? : "kernel");
+		ret = -E2BIG;
+		goto out;
+	}
+
+	*tevs = zalloc(ret * sizeof(*tev));
+	if (!*tevs) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	i = 0;
+	strlist__for_each_entry(node, entry->tevlist) {
+		tev = &(*tevs)[i++];
+		ret = parse_probe_trace_command(node->s, tev);
+		if (ret < 0)
+			goto out;
+		/* Set the uprobes attribute as same as original */
+		tev->uprobes = pev->uprobes;
+	}
+	ret = i;
+
+out:
+	probe_cache__delete(cache);
+	return ret;
+}
+
 static int convert_to_probe_trace_events(struct perf_probe_event *pev,
 					 struct probe_trace_event **tevs)
 {
@@ -2866,6 +2922,11 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
 	if (ret > 0)
 		return ret;
 
+	/* At first, we need to lookup cache entry */
+	ret = find_probe_trace_events_from_cache(pev, tevs);
+	if (ret > 0)
+		return ret;	/* Found in probe cache */
+
 	if (arch__prefers_symtab() && !perf_probe_event_need_dwarf(pev)) {
 		ret = find_probe_trace_events_from_map(pev, tevs);
 		if (ret > 0)
tools/perf/util/probe-file.c +19 -1
index 1c12c1a..a94ee47 100644
@@ -524,7 +524,7 @@ static bool streql(const char *a, const char *b)
 	return !strcmp(a, b);
 }
 
-static struct probe_cache_entry *
+struct probe_cache_entry *
 probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
 {
 	struct probe_cache_entry *entry = NULL;
@@ -548,6 +548,24 @@ found:
 	return entry;
 }
 
+struct probe_cache_entry *
+probe_cache__find_by_name(struct probe_cache *pcache,
+			  const char *group, const char *event)
+{
+	struct probe_cache_entry *entry = NULL;
+
+	list_for_each_entry(entry, &pcache->entries, node) {
+		/* Hit if same event name or same command-string */
+		if (streql(entry->pev.group, group) &&
+		    streql(entry->pev.event, event))
+			goto found;
+	}
+	entry = NULL;
+
+found:
+	return entry;
+}
+
 int probe_cache__add_entry(struct probe_cache *pcache,
 			   struct perf_probe_event *pev,
 			   struct probe_trace_event *tevs, int ntevs)
tools/perf/util/probe-file.h +4 -1
index d872e3d..910aa74 100644
@@ -38,5 +38,8 @@ int probe_cache__add_entry(struct probe_cache *pcache,
 int probe_cache__commit(struct probe_cache *pcache);
 void probe_cache__purge(struct probe_cache *pcache);
 void probe_cache__delete(struct probe_cache *pcache);
-
+struct probe_cache_entry *probe_cache__find(struct probe_cache *pcache,
+					    struct perf_probe_event *pev);
+struct probe_cache_entry *probe_cache__find_by_name(struct probe_cache *pcache,
+					const char *group, const char *event);
 #endif
#2 lore raw

PATCH v12 2/16 perf probe: Show all cached probes

In reply to Masami Hiramatsu

From: Masami Hiramatsu <[email protected]>

perf probe --list shows all cached probes when --cache is given. Each caches are shown with on which binary that probed. e.g.
-----

  # perf probe --cache vfs_read \$params
  # perf probe --cache -x /lib64/libc-2.17.so getaddrinfo \$params
  # perf probe --cache --list
  [kernel.kallsyms] (1466a0a250b5d0070c6d0f03c5fed30b237970a1):
  vfs_read $params
  /usr/lib64/libc-2.17.so (c31ffe7942bfd77b2fca8f9bd5709d387a86d3bc):
  getaddrinfo $params
  -----
Note that $params requires debuginfo.

---
Changes in v12:
- Rename strlist__for_each to strlist__for_each_entry.
Changes in v11:
- Make build_id_cache__list_all() returns strlist directly. (no error code)
- Harden build_id_cache__list_all() to check directory entries.
Changes in v7:
- Remove the top '/' from binary name if it is not a regular file.

---
 tools/perf/Documentation/perf-probe.txt |    8 ++
 tools/perf/builtin-probe.c              |    2 -
 tools/perf/util/build-id.c              |  108 ++++++++++++++++++++++++++++++-
 tools/perf/util/build-id.h              |    3 +
 tools/perf/util/probe-event.c           |    3 +
 tools/perf/util/probe-file.c            |   66 ++++++++++++++++++-
 tools/perf/util/probe-file.h            |    1 
 7 files changed, 184 insertions(+), 7 deletions(-)
tools/perf/Documentation/perf-probe.txt +6 -2
index 947db6f..5a70d45 100644
@@ -67,7 +67,10 @@ OPTIONS
 
 -l::
 --list[=[GROUP:]EVENT]::
-	List up current probe events. This can also accept filtering patterns of event names.
+	List up current probe events. This can also accept filtering patterns of
+	event names.
+	When this is used with --cache, perf shows all cached probes instead of
+	the live probes.
 
 -L::
 --line=::
@@ -110,8 +113,9 @@ OPTIONS
 	adding and removal operations.
 
 --cache::
-	Cache the probes (with --add option). Any events which successfully added
+	(With --add) Cache the probes. Any events which successfully added
 	are also stored in the cache file.
+	(With --list) Show cached probes.
 
 --max-probes=NUM::
 	Set the maximum number of probe points for an event. Default is 128.
tools/perf/builtin-probe.c +1 -1
index 3426232..0bb9084 100644
@@ -44,7 +44,7 @@
 
 #define DEFAULT_VAR_FILTER "!__k???tab_* & !__crc_*"
 #define DEFAULT_FUNC_FILTER "!_*"
-#define DEFAULT_LIST_FILTER "*:*"
+#define DEFAULT_LIST_FILTER "*"
 
 /* Session management structure */
 static struct {
tools/perf/util/build-id.c +106 -2

126 lines not on this page · raw message

tools/perf/util/build-id.h +3 -0
index d8c7f2f..b742e27 100644
@@ -30,8 +30,11 @@ bool perf_session__read_build_ids(struct perf_session *session, bool with_hits);
 int perf_session__write_buildid_table(struct perf_session *session, int fd);
 int perf_session__cache_build_ids(struct perf_session *session);
 
+char *build_id_cache__origname(const char *sbuild_id);
+char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size);
 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 			       bool is_kallsyms, bool is_vdso);
+struct strlist *build_id_cache__list_all(void);
 int build_id_cache__list_build_ids(const char *pathname,
 				   struct strlist **result);
 bool build_id_cache__cached(const char *sbuild_id);
tools/perf/util/probe-event.c +3 -0
index 47b6b8b..f81b5dd 100644
@@ -2366,6 +2366,9 @@ int show_perf_probe_events(struct strfilter *filter)
 
 	setup_pager();
 
+	if (probe_conf.cache)
+		return probe_cache__show_all_caches(filter);
+
 	ret = init_probe_symbol_maps(false);
 	if (ret < 0)
 		return ret;
tools/perf/util/probe-file.c +64 -2

85 lines not on this page · raw message

tools/perf/util/probe-file.h +1 -0
index 910aa74..0009b8a 100644
@@ -42,4 +42,5 @@ struct probe_cache_entry *probe_cache__find(struct probe_cache *pcache,
 					    struct perf_probe_event *pev);
 struct probe_cache_entry *probe_cache__find_by_name(struct probe_cache *pcache,
 					const char *group, const char *event);
+int probe_cache__show_all_caches(struct strfilter *filter);
 #endif
#3 lore raw

PATCH v12 3/16 perf probe: Remove caches when --cache is given

In reply to Masami Hiramatsu

From: Masami Hiramatsu <[email protected]>

perf-probe --del removes caches when --cache is given. Note that the delete pattern is not same as normal events.

If you cached probes with event name, --del "eventname" works as expected. However, if you skipped it, the cached probes doesn't have actual event name. In that case
--del "probe-desc" is required (wildcard is acceptable).
For example a cache entry has the probe-desc "vfs_read $params", you can remove it with --del 'vfs_read*'.

-----

  # perf probe --cache --list
  /[kernel.kallsyms] (1466a0a250b5d0070c6d0f03c5fed30b237970a1):
  vfs_read $params
  /usr/lib64/libc-2.17.so (c31ffe7942bfd77b2fca8f9bd5709d387a86d3bc):
  getaddrinfo $params
  # perf probe --cache --del vfs_read\*
  Removed cached event: probe:vfs_read
  # perf probe --cache --list
  /[kernel.kallsyms] (1466a0a250b5d0070c6d0f03c5fed30b237970a1):
  /usr/lib64/libc-2.17.so (c31ffe7942bfd77b2fca8f9bd5709d387a86d3bc):
  getaddrinfo $params
  -----

---
Changes in v12:
- Rename strlist__for_each to strlist__for_each_entry.
Changes in v11:
- Fix to check the result of purging cache entries.
- Rename probe_cache__remove_entries to probe_cache__filter_purge.
Changes in v9:
- Fix to show which event is deleted (Thanks Hemant!)
Changes in v4:
- move del_perf_probe_caches() into builtin-probe.c since command-line related delete procedure is there now.

---
 tools/perf/Documentation/perf-probe.txt |    1 +
 tools/perf/builtin-probe.c              |   29 +++++++++++++++++++++++++
 tools/perf/util/probe-file.c            |   36 ++++++++++++++++++++++++-------
 tools/perf/util/probe-file.h            |    2 ++
 4 files changed, 60 insertions(+), 8 deletions(-)
tools/perf/Documentation/perf-probe.txt +1 -0
index 5a70d45..8d09173 100644
@@ -116,6 +116,7 @@ OPTIONS
 	(With --add) Cache the probes. Any events which successfully added
 	are also stored in the cache file.
 	(With --list) Show cached probes.
+	(With --del) Remove cached probes.
 
 --max-probes=NUM::
 	Set the maximum number of probe points for an event. Default is 128.
tools/perf/builtin-probe.c +29 -0
index 0bb9084..a1a5cd1 100644
@@ -363,6 +363,32 @@ out_cleanup:
 	return ret;
 }
 
+static int del_perf_probe_caches(struct strfilter *filter)
+{
+	struct probe_cache *cache;
+	struct strlist *bidlist;
+	struct str_node *nd;
+	int ret;
+
+	bidlist = build_id_cache__list_all();
+	if (!bidlist) {
+		ret = -errno;
+		pr_debug("Failed to get buildids: %d\n", ret);
+		return ret ?: -ENOMEM;
+	}
+
+	strlist__for_each_entry(nd, bidlist) {
+		cache = probe_cache__new(nd->s);
+		if (!cache)
+			continue;
+		if (probe_cache__filter_purge(cache, filter) < 0 ||
+		    probe_cache__commit(cache) < 0)
+			pr_warning("Failed to remove entries for %s\n", nd->s);
+		probe_cache__delete(cache);
+	}
+	return 0;
+}
+
 static int perf_del_probe_events(struct strfilter *filter)
 {
 	int ret, ret2, ufd = -1, kfd = -1;
@@ -375,6 +401,9 @@ static int perf_del_probe_events(struct strfilter *filter)
 
 	pr_debug("Delete filter: \'%s\'\n", str);
 
+	if (probe_conf.cache)
+		return del_perf_probe_caches(filter);
+
 	/* Get current event names */
 	ret = probe_file__open_both(&kfd, &ufd, PF_FL_RW);
 	if (ret < 0)
tools/perf/util/probe-file.c +28 -8
index 156e3d8..6cb6ec0 100644
@@ -684,20 +684,40 @@ out:
 	return ret;
 }
 
+static bool probe_cache_entry__compare(struct probe_cache_entry *entry,
+				       struct strfilter *filter)
+{
+	char buf[128], *ptr = entry->spev;
+
+	if (entry->pev.event) {
+		snprintf(buf, 128, "%s:%s", entry->pev.group, entry->pev.event);
+		ptr = buf;
+	}
+	return strfilter__compare(filter, ptr);
+}
+
+int probe_cache__filter_purge(struct probe_cache *pcache,
+			      struct strfilter *filter)
+{
+	struct probe_cache_entry *entry, *tmp;
+
+	list_for_each_entry_safe(entry, tmp, &pcache->entries, node) {
+		if (probe_cache_entry__compare(entry, filter)) {
+			pr_info("Removed cached event: %s\n", entry->spev);
+			list_del_init(&entry->node);
+			probe_cache_entry__delete(entry);
+		}
+	}
+	return 0;
+}
+
 static int probe_cache__show_entries(struct probe_cache *pcache,
 				     struct strfilter *filter)
 {
 	struct probe_cache_entry *entry;
-	char buf[128], *ptr;
 
 	list_for_each_entry(entry, &pcache->entries, node) {
-		if (entry->pev.event) {
-			ptr = buf;
-			snprintf(buf, 128, "%s:%s",
-				 entry->pev.group, entry->pev.event);
-		} else
-			ptr = entry->spev;
-		if (strfilter__compare(filter, ptr))
+		if (probe_cache_entry__compare(entry, filter))
 			printf("%s\n", entry->spev);
 	}
 	return 0;
tools/perf/util/probe-file.h +2 -0
index 0009b8a..0ed1fc5 100644
@@ -38,6 +38,8 @@ int probe_cache__add_entry(struct probe_cache *pcache,
 int probe_cache__commit(struct probe_cache *pcache);
 void probe_cache__purge(struct probe_cache *pcache);
 void probe_cache__delete(struct probe_cache *pcache);
+int probe_cache__filter_purge(struct probe_cache *pcache,
+			      struct strfilter *filter);
 struct probe_cache_entry *probe_cache__find(struct probe_cache *pcache,
 					    struct perf_probe_event *pev);
 struct probe_cache_entry *probe_cache__find_by_name(struct probe_cache *pcache,
#4 lore raw

PATCH v12 4/16 perf/sdt: ELF support for SDT

In reply to Masami Hiramatsu

From: Hemant Kumar <[email protected]>

This patch serves 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.

A typical note entry in ".note.stapsdt" section is as follows :

|--nhdr.n_namesz--|
------------------------------------
| nhdr | "stapsdt" |
----- |----------------------------------|
| | <location> <base_address> |
| | <semaphore> |

nhdr.n_descsize |  "provider_name"   "note_name"   |
         |      |   <args>                         |
        -----   |----------------------------------|
                |      nhdr      |     "stapsdt"   |
                |...

The above shows an excerpt from the section ".note.stapsdt". 'nhdr' is a structure which has the note name size (n_namesz), note description size (n_desc_sz) and note type (n_type). So, in order to parse the note note info, we need nhdr to tell us where to start from. As can be seen from <sys/sdt.h>, the name of the SDT notes given is "stapsdt". But this is not the identifier of the note.
After that, we go to description of the note to find out its location, the address of the ".stapsdt.base" section and the semaphore address. Then, we find the provider name and the SDT marker name and then follow the arguments.

---
 tools/perf/util/symbol-elf.c |  252 ++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/symbol.h     |   22 ++++
 2 files changed, 274 insertions(+)
tools/perf/util/symbol-elf.c +252 -0
index 87a297d..e74ce17 100644
@@ -1781,6 +1781,258 @@ void kcore_extract__delete(struct kcore_extract *kce)
 	unlink(kce->extract_filename);
 }
 
+/**
+ * populate_sdt_note : Parse raw data and identify SDT note
+ * @elf: elf of the opened file
+ * @data: raw data of a section with description offset applied
+ * @len: note description size
+ * @type: type of the note
+ * @sdt_notes: List to add the SDT note
+ *
+ * Responsible for parsing the @data in section .note.stapsdt in @elf and
+ * if its an SDT note, it appends to @sdt_notes list.
+ */
+static int populate_sdt_note(Elf **elf, const char *data, size_t len,
+			     struct list_head *sdt_notes)
+{
+	const char *provider, *name;
+	struct sdt_note *tmp = NULL;
+	GElf_Ehdr ehdr;
+	GElf_Addr base_off = 0;
+	GElf_Shdr shdr;
+	int ret = -EINVAL;
+
+	union {
+		Elf64_Addr a64[NR_ADDR];
+		Elf32_Addr a32[NR_ADDR];
+	} buf;
+
+	Elf_Data dst = {
+		.d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
+		.d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, 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
+	};
+
+	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) {
+		pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
+		goto out_free_note;
+	}
+
+	/* 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;
+	}
+
+	if (gelf_getclass(*elf) == ELFCLASS32) {
+		memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
+		tmp->bit32 = true;
+	} else {
+		memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
+		tmp->bit32 = false;
+	}
+
+	if (!gelf_getehdr(*elf, &ehdr)) {
+		pr_debug("%s : cannot get elf header.\n", __func__);
+		ret = -EBADF;
+		goto out_free_name;
+	}
+
+	/* Adjust the prelink effect :
+	 * 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];
+		}
+	}
+
+	list_add_tail(&tmp->note_list, sdt_notes);
+	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 : constructs a list of SDT notes
+ * @elf : elf to look into
+ * @sdt_notes : empty list_head
+ *
+ * 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;
+	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))) {
+			/* Check the type of the note */
+			if (nhdr.n_type != SDT_NOTE_TYPE)
+				goto out_ret;
+
+			ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
+						nhdr.n_descsz, sdt_notes);
+			if (ret < 0)
+				goto out_ret;
+		}
+	}
+	if (list_empty(sdt_notes))
+		ret = -ENOENT;
+
+out_ret:
+	return ret;
+}
+
+/**
+ * get_sdt_note_list : Wrapper to construct a list of sdt notes
+ * @head : empty list_head
+ * @target : file to find SDT notes from
+ *
+ * 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, PERF_ELF_C_READ_MMAP, NULL);
+	if (!elf) {
+		ret = -EBADF;
+		goto out_close;
+	}
+	ret = construct_sdt_notes_list(elf, head);
+	elf_end(elf);
+out_close:
+	close(fd);
+	return ret;
+}
+
+/**
+ * cleanup_sdt_note_list : free the sdt notes' list
+ * @sdt_notes: sdt notes' list
+ *
+ * Free up the SDT notes in @sdt_notes.
+ * Returns the number of SDT notes free'd.
+ */
+int cleanup_sdt_note_list(struct list_head *sdt_notes)
+{
+	struct sdt_note *tmp, *pos;
+	int nr_free = 0;
+
+	list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
+		list_del(&pos->note_list);
+		free(pos->name);
+		free(pos->provider);
+		free(pos);
+		nr_free++;
+	}
+	return nr_free;
+}
+
+/**
+ * sdt_notes__get_count: Counts the number of sdt events
+ * @start: list_head to sdt_notes list
+ *
+ * Returns the number of SDT notes in a list
+ */
+int sdt_notes__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;
+}
+
 void symbol__elf_init(void)
 {
 	elf_version(EV_CURRENT);
tools/perf/util/symbol.h +22 -0
index b10d558..699f7cb 100644
@@ -342,4 +342,26 @@ void arch__sym_update(struct symbol *s, GElf_Sym *sym);
 
 int arch__choose_best_symbol(struct symbol *syma, struct symbol *symb);
 
+/* 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);
+int cleanup_sdt_note_list(struct list_head *sdt_notes);
+int sdt_notes__get_count(struct list_head *start);
+
+#define SDT_BASE_SCN ".stapsdt.base"
+#define SDT_NOTE_SCN  ".note.stapsdt"
+#define SDT_NOTE_TYPE 3
+#define SDT_NOTE_NAME "stapsdt"
+#define NR_ADDR 3
+
 #endif /* __PERF_SYMBOL */
#5 lore raw

PATCH v12 5/16 perf probe: Add group name support

In reply to Masami Hiramatsu

From: Masami Hiramatsu <[email protected]>

Allow user to set group name for adding new event. Note that user must ensure that the group name doesn't conflict with existing group name carefully. E.g. Existing group name can conflict with other events. Especially, using the group name reserved for kernel modules can hide kernel embedded events when loading modules.

---
Changes in v4:
- Update Documentation/perf-probe.txt too.

---
 tools/perf/Documentation/perf-probe.txt |   10 ++++++----
 tools/perf/util/probe-event.c           |   23 ++++++++++++++---------
 2 files changed, 20 insertions(+), 13 deletions(-)
tools/perf/Documentation/perf-probe.txt +6 -4
index 8d09173..7a258e9 100644
@@ -143,16 +143,18 @@ PROBE SYNTAX
 Probe points are defined by following syntax.
 
     1) Define event based on function name
-     [EVENT=]FUNC[@SRC][:RLN|+OFFS|%return|;PTN] [ARG ...]
+     [[GROUP:]EVENT=]FUNC[@SRC][:RLN|+OFFS|%return|;PTN] [ARG ...]
 
     2) Define event based on source file with line number
-     [EVENT=]SRC:ALN [ARG ...]
+     [[GROUP:]EVENT=]SRC:ALN [ARG ...]
 
     3) Define event based on source file with lazy pattern
-     [EVENT=]SRC;PTN [ARG ...]
+     [[GROUP:]EVENT=]SRC;PTN [ARG ...]
 
 
-'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function. Currently, event group name is set as 'probe'.
+'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function. You can also specify a group name by 'GROUP', if omitted, set 'probe' is used for kprobe and 'probe_<bin>' is used for uprobe.
+Note that using existing group name can conflict with other events. Especially, using the group name reserved for kernel modules can hide embedded events in the
+modules.
 'FUNC' specifies a probed function name, and it may have one of the following options; '+OFFS' is the offset from function entry address in bytes, ':RLN' is the relative-line number from function entry line, and '%return' means that it probes function return. And ';PTN' means lazy matching pattern (see LAZY MATCHING). Note that ';PTN' must be the end of the probe point definition.  In addition, '@SRC' specifies a source file which has that function.
 It is also possible to specify a probe point by the source line number or lazy matching by using 'SRC:ALN' or 'SRC;PTN' syntax, where 'SRC' is the source file path, ':ALN' is the line number and ';PTN' is the lazy matching pattern.
 'ARG' specifies the arguments of this probe point, (see PROBE ARGUMENT).
tools/perf/util/probe-event.c +14 -9
index f81b5dd..0201f66 100644
@@ -1206,10 +1206,8 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 	bool file_spec = false;
 	/*
 	 * <Syntax>
-	 * perf probe [EVENT=]SRC[:LN|;PTN]
-	 * perf probe [EVENT=]FUNC[@SRC][+OFFS|%return|:LN|;PAT]
-	 *
-	 * TODO:Group name support
+	 * perf probe [GRP:][EVENT=]SRC[:LN|;PTN]
+	 * perf probe [GRP:][EVENT=]FUNC[@SRC][+OFFS|%return|:LN|;PAT]
 	 */
 	if (!arg)
 		return -EINVAL;
@@ -1218,11 +1216,19 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 	if (ptr && *ptr == '=') {	/* Event name */
 		*ptr = '\0';
 		tmp = ptr + 1;
-		if (strchr(arg, ':')) {
-			semantic_error("Group name is not supported yet.\n");
-			return -ENOTSUP;
-		}
+		ptr = strchr(arg, ':');
+		if (ptr) {
+			*ptr = '\0';
+			if (!is_c_func_name(arg))
+				goto not_fname;
+			pev->group = strdup(arg);
+			if (!pev->group)
+				return -ENOMEM;
+			arg = ptr + 1;
+		} else
+			pev->group = NULL;
 		if (!is_c_func_name(arg)) {
+not_fname:
 			semantic_error("%s is bad for event name -it must "
 				       "follow C symbol-naming rule.\n", arg);
 			return -EINVAL;
@@ -1230,7 +1236,6 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 		pev->event = strdup(arg);
 		if (pev->event == NULL)
 			return -ENOMEM;
-		pev->group = NULL;
 		arg = tmp;
 	}
 
#6 lore raw

PATCH v12 6/16 perf buildid-cache: Scan and import user SDT events to probe cache

In reply to Masami Hiramatsu

From: Masami Hiramatsu <[email protected]>

perf buildid-cache --add <binary> scans given binary and add the SDT events to probe cache. "sdt_" prefix is appended for all SDT providers to avoid event-name clash with other pre-defined events. It is possible to use the cached SDT events as other cached events, via perf probe --add "sdt_<provider>:<event>=<event>".

e.g.
----

  # perf buildid-cache --add /lib/libc-2.17.so
  # perf probe --cache --list | head -n 5
  /usr/lib/libc-2.17.so (a6fb821bdf53660eb2c29f778757aef294d3d392):
  sdt_libc:setjmp=setjmp
  sdt_libc:longjmp=longjmp
  sdt_libc:longjmp_target=longjmp_target
  sdt_libc:memory_heap_new=memory_heap_new
  # perf probe -x /usr/lib/libc-2.17.so \
    -a sdt_libc:memory_heap_new=memory_heap_new
  Added new event:
    sdt_libc:memory_heap_new (on memory_heap_new
   in /usr/lib/libc-2.17.so)

You can now use it in all perf tools, such as:

perf record -e sdt_libc:memory_heap_new -aR sleep 1

  # perf probe -l
    sdt_libc:memory_heap_new (on new_heap+183 in /usr/lib/libc-2.17.so)
  ----

Note that SDT event entries in probe-cache file is somewhat different from normal cached events. Normal one starts with "#", but SDTs are starting with "%".

---
Changes in v11:
- Warn if SDT scanning/updating are failed.
Changes in v10:
- Update Documentation/perf-buildid-cache.txt too.
Changes in v4:
- Fix a bug to copy correct group name to entries.
- Fix to consolidate same-name entries.

---
 tools/perf/Documentation/perf-buildid-cache.txt |    3 +
 tools/perf/util/build-id.c                      |   30 ++++++++++
 tools/perf/util/probe-file.c                    |   69 ++++++++++++++++++++++-
 tools/perf/util/probe-file.h                    |    2 +
 4 files changed, 101 insertions(+), 3 deletions(-)
tools/perf/Documentation/perf-buildid-cache.txt +3 -0
index dd07b55..058064d 100644
@@ -15,6 +15,9 @@ DESCRIPTION
 This command manages the build-id cache. It can add, remove, update and purge
 files to/from the cache. In the future it should as well set upper limits for
 the space used by the cache, etc.
+This also scans the target binary for SDT (Statically Defined Tracing) and
+record it along with the buildid-cache, which will be used by perf-probe.
+For more details, see linkperf:perf-probe[1].
 
 OPTIONS
 -------
tools/perf/util/build-id.c +30 -0
index 1c49620..e1a1640 100644
@@ -17,6 +17,7 @@
 #include "tool.h"
 #include "header.h"
 #include "vdso.h"
+#include "probe-file.h"
 
 
 static bool no_buildid_cache;
@@ -532,6 +533,30 @@ int build_id_cache__list_build_ids(const char *pathname,
 	return ret;
 }
 
+#ifdef HAVE_LIBELF_SUPPORT
+static int build_id_cache__add_sdt_cache(const char *sbuild_id,
+					  const char *realname)
+{
+	struct probe_cache *cache;
+	int ret;
+
+	cache = probe_cache__new(sbuild_id);
+	if (!cache)
+		return -1;
+
+	ret = probe_cache__scan_sdt(cache, realname);
+	if (ret >= 0) {
+		pr_debug("Found %d SDTs in %s\n", ret, realname);
+		if (probe_cache__commit(cache) < 0)
+			ret = -1;
+	}
+	probe_cache__delete(cache);
+	return ret;
+}
+#else
+#define build_id_cache__add_sdt_cache(sbuild_id, realname) (0)
+#endif
+
 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 			  bool is_kallsyms, bool is_vdso)
 {
@@ -589,6 +614,11 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
 
 	if (symlink(tmp, linkname) == 0)
 		err = 0;
+
+	/* Update SDT cache : error is just warned */
+	if (build_id_cache__add_sdt_cache(sbuild_id, realname) < 0)
+		pr_debug("Failed to update/scan SDT cache for %s\n", realname);
+
 out_free:
 	if (!is_kallsyms)
 		free(realname);
tools/perf/util/probe-file.c +66 -3

97 lines not on this page · raw message

tools/perf/util/probe-file.h +2 -0
index 0ed1fc5..ddf5ae2 100644
@@ -8,6 +8,7 @@
 /* Cache of probe definitions */
 struct probe_cache_entry {
 	struct list_head	node;
+	bool			sdt;
 	struct perf_probe_event pev;
 	char			*spev;
 	struct strlist		*tevlist;
@@ -35,6 +36,7 @@ struct probe_cache *probe_cache__new(const char *target);
 int probe_cache__add_entry(struct probe_cache *pcache,
 			   struct perf_probe_event *pev,
 			   struct probe_trace_event *tevs, int ntevs);
+int probe_cache__scan_sdt(struct probe_cache *pcache, const char *pathname);
 int probe_cache__commit(struct probe_cache *pcache);
 void probe_cache__purge(struct probe_cache *pcache);
 void probe_cache__delete(struct probe_cache *pcache);
#7 lore raw

PATCH v12 7/16 perf probe: Accept %sdt and %cached event name

In reply to Masami Hiramatsu

From: Masami Hiramatsu <[email protected]>

To improbe usability, support %[PROVIDER:]SDTEVENT format to add new probes on SDT and cached events.

e.g.
----

  # perf probe -x /lib/libc-2.17.so  %lll_lock_wait_private
  Added new event:
    sdt_libc:lll_lock_wait_private (on %lll_lock_wait_private in
  /usr/lib/libc-2.17.so)

You can now use it in all perf tools, such as:

perf record -e sdt_libc:lll_lock_wait_private -aR sleep 1

  # perf probe -l | more
    sdt_libc:lll_lock_wait_private (on __lll_lock_wait_private+21
   in /usr/lib/libc-2.17.so)
  ----

Note that this is not only for SDT events, but also normal events with event-name.

e.g. define "myevent" on cache (-n doesn't add the real probe)
----

  # perf probe -x ./perf --cache -n --add 'myevent=dso__load $params'
  ----
  Reuse the "myevent" from cache as below.
  ----
  # perf probe -x ./perf %myevent
  ----

---
Changes in v10:
- Update Documentation/perf-probe.txt to add a link about SDT.
Changes in v7:
- Fix a bug to return an error if no SDT/cached events found in cache.

---
 tools/perf/Documentation/perf-probe.txt |    9 +++
 tools/perf/util/probe-event.c           |   82 ++++++++++++++++++++++---------
 tools/perf/util/probe-event.h           |    1 
 tools/perf/util/probe-file.c            |    9 +++
 4 files changed, 76 insertions(+), 25 deletions(-)
tools/perf/Documentation/perf-probe.txt +8 -1
index 7a258e9..39e3870 100644
@@ -151,6 +151,8 @@ Probe points are defined by following syntax.
     3) Define event based on source file with lazy pattern
      [[GROUP:]EVENT=]SRC;PTN [ARG ...]
 
+    4) Pre-defined SDT events or cached event with name
+     %[PROVIDER:]SDTEVENT
 
 'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function. You can also specify a group name by 'GROUP', if omitted, set 'probe' is used for kprobe and 'probe_<bin>' is used for uprobe.
 Note that using existing group name can conflict with other events. Especially, using the group name reserved for kernel modules can hide embedded events in the
@@ -158,6 +160,11 @@ modules.
 'FUNC' specifies a probed function name, and it may have one of the following options; '+OFFS' is the offset from function entry address in bytes, ':RLN' is the relative-line number from function entry line, and '%return' means that it probes function return. And ';PTN' means lazy matching pattern (see LAZY MATCHING). Note that ';PTN' must be the end of the probe point definition.  In addition, '@SRC' specifies a source file which has that function.
 It is also possible to specify a probe point by the source line number or lazy matching by using 'SRC:ALN' or 'SRC;PTN' syntax, where 'SRC' is the source file path, ':ALN' is the line number and ';PTN' is the lazy matching pattern.
 'ARG' specifies the arguments of this probe point, (see PROBE ARGUMENT).
+'SDTEVENT' and 'PROVIDER' is the pre-defined event name which is defined by user SDT (Statically Defined Tracing) or the pre-cached probes with event name.
+Note that before using the SDT event, the target binary (on which SDT events are defined) must be scanned by linkperf:perf-buildid-cache[1] to make SDT events as cached events.
+
+For details of the SDT, see below.
+https://sourceware.org/gdb/onlinedocs/gdb/Static-Probe-Points.html
 
 PROBE ARGUMENT
 --------------
@@ -237,4 +244,4 @@ Add probes at malloc() function on libc
 
 SEE ALSO
 --------
-linkperf:perf-trace[1], linkperf:perf-record[1]
+linkperf:perf-trace[1], linkperf:perf-record[1], linkperf:perf-buildid-cache[1]
tools/perf/util/probe-event.c +58 -24

124 lines not on this page · raw message

tools/perf/util/probe-event.h +1 -0
index 432b690..e18ea9f 100644
@@ -85,6 +85,7 @@ struct perf_probe_event {
 	char			*group;	/* Group name */
 	struct perf_probe_point	point;	/* Probe point */
 	int			nargs;	/* Number of arguments */
+	bool			sdt;	/* SDT/cached event flag */
 	bool			uprobes;	/* Uprobe event flag */
 	char			*target;	/* Target binary */
 	struct perf_probe_arg	*args;	/* Arguments */
tools/perf/util/probe-file.c +9 -0
index 5b563b2..b642d06 100644
@@ -547,6 +547,15 @@ probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
 		return NULL;
 
 	list_for_each_entry(entry, &pcache->entries, node) {
+		if (pev->sdt) {
+			if (entry->pev.event &&
+			    streql(entry->pev.event, pev->event) &&
+			    (!pev->group ||
+			     streql(entry->pev.group, pev->group)))
+				goto found;
+
+			continue;
+		}
 		/* Hit if same event name or same command-string */
 		if ((pev->event &&
 		     (streql(entry->pev.group, pev->group) &&
#8 lore raw

PATCH v12 8/16 perf-list: Show SDT and pre-cached events

In reply to Masami Hiramatsu

From: Masami Hiramatsu <[email protected]>

Show SDT and pre-cached events by perf-list with "sdt". This also shows the binary and build-id where the events are placed only when there are same name events on different binaries. e.g.
----

  # perf list sdt

List of pre-defined events (to be used in -e):

    sdt_libc:lll_futex_wake                            [SDT event]
    sdt_libc:lll_lock_wait_private                     [SDT event]
    sdt_libc:longjmp                                   [SDT event]
    sdt_libc:longjmp_target                            [SDT event]
  ...
    sdt_libstdcxx:rethrow@/usr/bin/gcc(0cc207fc4b27)   [SDT event]
    sdt_libstdcxx:rethrow@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)
    sdt_libstdcxx:throw@/usr/bin/gcc(0cc207fc4b27)     [SDT event]
    sdt_libstdcxx:throw@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)

----

The binary path and build-id are shown in below format;

<GROUP>:<EVENT>@<PATH>(<BUILD-ID>)

---
Changes in v12:
- Rename strlist__for_each to strlist__for_each_entry.
Changes in v9:
- Update list_usage too. (Thanks Hemant!)
Changes in v5:
- Fix a build error for minimal option.
Changes in v4:
- Update patch description.
- Change event list format.

---
 tools/perf/builtin-list.c      |    6 ++-
 tools/perf/util/parse-events.c |   82 ++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/parse-events.h |    2 +
 tools/perf/util/probe-file.h   |    9 ++++
 4 files changed, 98 insertions(+), 1 deletion(-)
tools/perf/builtin-list.c +5 -1
index 5e22db4..88ee419 100644
@@ -25,7 +25,7 @@ int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 		OPT_END()
 	};
 	const char * const list_usage[] = {
-		"perf list [hw|sw|cache|tracepoint|pmu|event_glob]",
+		"perf list [hw|sw|cache|tracepoint|pmu|sdt|event_glob]",
 		NULL
 	};
 
@@ -62,6 +62,8 @@ int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 			print_hwcache_events(NULL, raw_dump);
 		else if (strcmp(argv[i], "pmu") == 0)
 			print_pmu_events(NULL, raw_dump);
+		else if (strcmp(argv[i], "sdt") == 0)
+			print_sdt_events(NULL, NULL, raw_dump);
 		else if ((sep = strchr(argv[i], ':')) != NULL) {
 			int sep_idx;
 
@@ -76,6 +78,7 @@ int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 
 			s[sep_idx] = '\0';
 			print_tracepoint_events(s, s + sep_idx + 1, raw_dump);
+			print_sdt_events(s, s + sep_idx + 1, raw_dump);
 			free(s);
 		} else {
 			if (asprintf(&s, "*%s*", argv[i]) < 0) {
@@ -89,6 +92,7 @@ int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 			print_hwcache_events(s, raw_dump);
 			print_pmu_events(s, raw_dump);
 			print_tracepoint_events(NULL, s, raw_dump);
+			print_sdt_events(NULL, s, raw_dump);
 			free(s);
 		}
 	}
tools/perf/util/parse-events.c +82 -0

100 lines not on this page · raw message

tools/perf/util/parse-events.h +2 -0
index 46c05cc..7325c9a 100644
@@ -183,6 +183,8 @@ void print_symbol_events(const char *event_glob, unsigned type,
 void print_tracepoint_events(const char *subsys_glob, const char *event_glob,
 			     bool name_only);
 int print_hwcache_events(const char *event_glob, bool name_only);
+void print_sdt_events(const char *subsys_glob, const char *event_glob,
+		      bool name_only);
 int is_valid_tracepoint(const char *event_string);
 
 int valid_event_mount(const char *eventfs);
tools/perf/util/probe-file.h +9 -0
index ddf5ae2..b2b4c39 100644
@@ -22,6 +22,8 @@ struct probe_cache {
 #define PF_FL_UPROBE	1
 #define PF_FL_RW	2
 
+/* probe-file.c depends on libelf */
+#ifdef HAVE_LIBELF_SUPPORT
 int probe_file__open(int flag);
 int probe_file__open_both(int *kfd, int *ufd, int flag);
 struct strlist *probe_file__get_namelist(int fd);
@@ -47,4 +49,11 @@ struct probe_cache_entry *probe_cache__find(struct probe_cache *pcache,
 struct probe_cache_entry *probe_cache__find_by_name(struct probe_cache *pcache,
 					const char *group, const char *event);
 int probe_cache__show_all_caches(struct strfilter *filter);
+#else	/* ! HAVE_LIBELF_SUPPORT */
+static inline struct probe_cache *probe_cache__new(const char *tgt __maybe_unused)
+{
+	return NULL;
+}
+#define probe_cache__delete(pcache) do {} while (0)
+#endif
 #endif
#9 lore raw

[tip:perf/core] perf list: Show SDT and pre-cached events

perf list: Show SDT and pre-cached events
Commit-ID:  40218daea1db1f95f1f10e58ebd43b8adf1c6c61
Gitweb:     http://git.kernel.org/tip/40218daea1db1f95f1f10e58ebd43b8adf1c6c61
Author:     Masami Hiramatsu <[email protected]>
AuthorDate: Fri, 24 Jun 2016 18:06:46 +0900
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Wed, 13 Jul 2016 23:09:07 -0300

perf list: Show SDT and pre-cached events

Show SDT and pre-cached events by perf-list with "sdt". This also shows the binary and build-id where the events are placed only when there are same name events on different binaries.

e.g.:

  # perf list sdt

List of pre-defined events (to be used in -e):

    sdt_libc:lll_futex_wake                            [SDT event]
    sdt_libc:lll_lock_wait_private                     [SDT event]
    sdt_libc:longjmp                                   [SDT event]
    sdt_libc:longjmp_target                            [SDT event]
  ...
    sdt_libstdcxx:rethrow@/usr/bin/gcc(0cc207fc4b27)   [SDT event]
    sdt_libstdcxx:rethrow@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)
    sdt_libstdcxx:throw@/usr/bin/gcc(0cc207fc4b27)     [SDT event]
    sdt_libstdcxx:throw@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)

The binary path and build-id are shown in below format;

<GROUP>:<EVENT>@<PATH>(<BUILD-ID>)

---
 tools/perf/builtin-list.c      |  6 +++-
 tools/perf/util/parse-events.c | 82 ++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/parse-events.h |  2 ++
 tools/perf/util/probe-file.h   |  9 +++++
 4 files changed, 98 insertions(+), 1 deletion(-)
tools/perf/builtin-list.c +5 -1
index 5e22db4..88ee419 100644
@@ -25,7 +25,7 @@ int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 		OPT_END()
 	};
 	const char * const list_usage[] = {
-		"perf list [hw|sw|cache|tracepoint|pmu|event_glob]",
+		"perf list [hw|sw|cache|tracepoint|pmu|sdt|event_glob]",
 		NULL
 	};
 
@@ -62,6 +62,8 @@ int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 			print_hwcache_events(NULL, raw_dump);
 		else if (strcmp(argv[i], "pmu") == 0)
 			print_pmu_events(NULL, raw_dump);
+		else if (strcmp(argv[i], "sdt") == 0)
+			print_sdt_events(NULL, NULL, raw_dump);
 		else if ((sep = strchr(argv[i], ':')) != NULL) {
 			int sep_idx;
 
@@ -76,6 +78,7 @@ int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 
 			s[sep_idx] = '\0';
 			print_tracepoint_events(s, s + sep_idx + 1, raw_dump);
+			print_sdt_events(s, s + sep_idx + 1, raw_dump);
 			free(s);
 		} else {
 			if (asprintf(&s, "*%s*", argv[i]) < 0) {
@@ -89,6 +92,7 @@ int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 			print_hwcache_events(s, raw_dump);
 			print_pmu_events(s, raw_dump);
 			print_tracepoint_events(NULL, s, raw_dump);
+			print_sdt_events(NULL, s, raw_dump);
 			free(s);
 		}
 	}
tools/perf/util/parse-events.c +82 -0

100 lines not on this page · raw message

tools/perf/util/parse-events.h +2 -0
index 0bd664d..b4aa7eb 100644
@@ -183,6 +183,8 @@ void print_symbol_events(const char *event_glob, unsigned type,
 void print_tracepoint_events(const char *subsys_glob, const char *event_glob,
 			     bool name_only);
 int print_hwcache_events(const char *event_glob, bool name_only);
+void print_sdt_events(const char *subsys_glob, const char *event_glob,
+		      bool name_only);
 int is_valid_tracepoint(const char *event_string);
 
 int valid_event_mount(const char *eventfs);
tools/perf/util/probe-file.h +9 -0
index cafbe1d..9577b5c 100644
@@ -24,6 +24,8 @@ struct probe_cache {
 #define for_each_probe_cache_entry(entry, pcache) \
 	list_for_each_entry(entry, &pcache->entries, node)
 
+/* probe-file.c depends on libelf */
+#ifdef HAVE_LIBELF_SUPPORT
 int probe_file__open(int flag);
 int probe_file__open_both(int *kfd, int *ufd, int flag);
 struct strlist *probe_file__get_namelist(int fd);
@@ -52,4 +54,11 @@ struct probe_cache_entry *probe_cache__find(struct probe_cache *pcache,
 struct probe_cache_entry *probe_cache__find_by_name(struct probe_cache *pcache,
 					const char *group, const char *event);
 int probe_cache__show_all_caches(struct strfilter *filter);
+#else	/* ! HAVE_LIBELF_SUPPORT */
+static inline struct probe_cache *probe_cache__new(const char *tgt __maybe_unused)
+{
+	return NULL;
+}
+#define probe_cache__delete(pcache) do {} while (0)
+#endif
 #endif
#10 lore raw

PATCH v12 9/16 perf-list: Skip SDTs placed in invalid binaries

In reply to Masami Hiramatsu

From: Masami Hiramatsu <[email protected]>

Skip SDTs placed in invalid (non-exist, or older version) binaries. Note that perf-probe --cache --list and perf-probe --cache --del still handle all the caches including invalid binaries.

---
Changes in v7:
- Validate build-id via sysfs if it is for kallsyms,
Changes in v4:
- Rename a parameter 'valid' to 'validonly' :)

---
 tools/perf/builtin-probe.c     |    2 +-
 tools/perf/util/build-id.c     |   33 ++++++++++++++++++++++++++++++++-
 tools/perf/util/build-id.h     |    2 +-
 tools/perf/util/parse-events.c |    2 +-
 tools/perf/util/probe-file.c   |    2 +-
 5 files changed, 36 insertions(+), 5 deletions(-)
tools/perf/builtin-probe.c +1 -1
index a1a5cd1..de75af5 100644
@@ -370,7 +370,7 @@ static int del_perf_probe_caches(struct strfilter *filter)
 	struct str_node *nd;
 	int ret;
 
-	bidlist = build_id_cache__list_all();
+	bidlist = build_id_cache__list_all(false);
 	if (!bidlist) {
 		ret = -errno;
 		pr_debug("Failed to get buildids: %d\n", ret);
tools/perf/util/build-id.c +32 -1
index e1a1640..8e86a83 100644
@@ -206,6 +206,31 @@ out:
 	return ret;
 }
 
+/* Check if the given build_id cache is valid on current running system */
+static bool build_id_cache__valid_id(char *sbuild_id)
+{
+	char real_sbuild_id[SBUILD_ID_SIZE] = "";
+	char *pathname;
+	int ret = 0;
+	bool result = false;
+
+	pathname = build_id_cache__origname(sbuild_id);
+	if (!pathname)
+		return false;
+
+	if (!strcmp(pathname, DSO__NAME_KALLSYMS))
+		ret = sysfs__sprintf_build_id("/", real_sbuild_id);
+	else if (pathname[0] == '/')
+		ret = filename__sprintf_build_id(pathname, real_sbuild_id);
+	else
+		ret = -EINVAL;	/* Should we support other special DSO cache? */
+	if (ret >= 0)
+		result = (strcmp(sbuild_id, real_sbuild_id) == 0);
+	free(pathname);
+
+	return result;
+}
+
 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso)
 {
 	return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : "elf");
@@ -433,13 +458,17 @@ static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 	return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 }
 
-struct strlist *build_id_cache__list_all(void)
+struct strlist *build_id_cache__list_all(bool validonly)
 {
 	struct strlist *toplist, *linklist = NULL, *bidlist;
 	struct str_node *nd, *nd2;
 	char *topdir, *linkdir = NULL;
 	char sbuild_id[SBUILD_ID_SIZE];
 
+	/* for filename__ functions */
+	if (validonly)
+		symbol__init(NULL);
+
 	/* Open the top-level directory */
 	if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 		return NULL;
@@ -470,6 +499,8 @@ struct strlist *build_id_cache__list_all(void)
 			if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 				     nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 				goto err_out;
+			if (validonly && !build_id_cache__valid_id(sbuild_id))
+				continue;
 			if (strlist__add(bidlist, sbuild_id) < 0)
 				goto err_out;
 		}
tools/perf/util/build-id.h +1 -1
index b742e27..64e740f 100644
@@ -34,7 +34,7 @@ char *build_id_cache__origname(const char *sbuild_id);
 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size);
 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 			       bool is_kallsyms, bool is_vdso);
-struct strlist *build_id_cache__list_all(void);
+struct strlist *build_id_cache__list_all(bool validonly);
 int build_id_cache__list_build_ids(const char *pathname,
 				   struct strlist **result);
 bool build_id_cache__cached(const char *sbuild_id);
tools/perf/util/parse-events.c +1 -1
index 131dfd3..b5d1f57 100644
@@ -2002,7 +2002,7 @@ void print_sdt_events(const char *subsys_glob, const char *event_glob,
 		pr_debug("Failed to allocate new strlist for SDT\n");
 		return;
 	}
-	bidlist = build_id_cache__list_all();
+	bidlist = build_id_cache__list_all(true);
 	if (!bidlist) {
 		pr_debug("Failed to get buildids: %d\n", errno);
 		return;
tools/perf/util/probe-file.c +1 -1
index b642d06..ef4e259 100644
@@ -806,7 +806,7 @@ int probe_cache__show_all_caches(struct strfilter *filter)
 	pr_debug("list cache with filter: %s\n", buf);
 	free(buf);
 
-	bidlist = build_id_cache__list_all();
+	bidlist = build_id_cache__list_all(false);
 	if (!bidlist) {
 		pr_debug("Failed to get buildids: %d\n", errno);
 		return -EINVAL;
#11 lore raw

PATCH v12 10/16 perf: probe-cache: Add for_each_probe_cache_entry() wrapper

In reply to Masami Hiramatsu

Add for_each_probe_cache_entry() wrapper macro
for hiding list in probe_cache.

---
Changes in v10:
- Splitted from "perf probe: Allow wildcard for cached events"

---
 tools/perf/util/probe-file.c |    8 ++++----
 tools/perf/util/probe-file.h |    2 ++
 2 files changed, 6 insertions(+), 4 deletions(-)
tools/perf/util/probe-file.c +4 -4
index ef4e259..39469c0 100644
@@ -546,7 +546,7 @@ probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
 	if (!cmd)
 		return NULL;
 
-	list_for_each_entry(entry, &pcache->entries, node) {
+	for_each_probe_cache_entry(entry, pcache) {
 		if (pev->sdt) {
 			if (entry->pev.event &&
 			    streql(entry->pev.event, pev->event) &&
@@ -576,7 +576,7 @@ probe_cache__find_by_name(struct probe_cache *pcache,
 {
 	struct probe_cache_entry *entry = NULL;
 
-	list_for_each_entry(entry, &pcache->entries, node) {
+	for_each_probe_cache_entry(entry, pcache) {
 		/* Hit if same event name or same command-string */
 		if (streql(entry->pev.group, group) &&
 		    streql(entry->pev.event, event))
@@ -746,7 +746,7 @@ int probe_cache__commit(struct probe_cache *pcache)
 	if (ret < 0)
 		goto out;
 
-	list_for_each_entry(entry, &pcache->entries, node) {
+	for_each_probe_cache_entry(entry, pcache) {
 		ret = probe_cache_entry__write(entry, pcache->fd);
 		pr_debug("Cache committed: %d\n", ret);
 		if (ret < 0)
@@ -788,7 +788,7 @@ static int probe_cache__show_entries(struct probe_cache *pcache,
 {
 	struct probe_cache_entry *entry;
 
-	list_for_each_entry(entry, &pcache->entries, node) {
+	for_each_probe_cache_entry(entry, pcache) {
 		if (probe_cache_entry__compare(entry, filter))
 			printf("%s\n", entry->spev);
 	}
tools/perf/util/probe-file.h +2 -0
index b2b4c39..837f530 100644
@@ -21,6 +21,8 @@ struct probe_cache {
 
 #define PF_FL_UPROBE	1
 #define PF_FL_RW	2
+#define for_each_probe_cache_entry(entry, pcache) \
+	list_for_each_entry(entry, &pcache->entries, node)
 
 /* probe-file.c depends on libelf */
 #ifdef HAVE_LIBELF_SUPPORT
#12 lore raw

PATCH v12 11/16 perf probe: Allow wildcard for cached events

In reply to Masami Hiramatsu

Allo glob wildcard for reusing cached/SDT events. E.g.

  # perf probe -x /usr/lib64/libc-2.20.so -a %sdt_libc:\*

This example adds probes for all SDT in libc.
Note that the SDTs must have been scanned by perf buildid-cache.

---
Changes in v12:
- Rename strlist__for_each to strlist__for_each_entry.
Changes in v10:
- Split off bugfix, adding interface, and target search patches.
- Do not export clear_probe_trace_events().
Changes in v7:
- Continue to search caches if a build-id cache has no probe cache.
- Make probe_cache__open() to accept DSO__NAME_KALLSYMS for kernel.
- Fix to add probes correctly when a wildcard matchs both of uprobes and kprobes.
Changes in v5.1:
- Fix a SEGV bug when a group name is omitted. (Thanks Hemant!)

---
 tools/perf/util/probe-event.c |  107 +++++++++++++++++++++++++++++++++++++++--
 tools/perf/util/probe-file.c  |   38 ++++++++++++---
 tools/perf/util/probe-file.h  |    3 +
 3 files changed, 138 insertions(+), 10 deletions(-)
tools/perf/util/probe-event.c +103 -4
index 7f79a83..2fb828f 100644
@@ -1204,7 +1204,7 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
 	ptr = strchr(*arg, ':');
 	if (ptr) {
 		*ptr = '\0';
-		if (!is_c_func_name(*arg))
+		if (!pev->sdt && !is_c_func_name(*arg))
 			goto ng_name;
 		pev->group = strdup(*arg);
 		if (!pev->group)
@@ -1212,7 +1212,7 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
 		*arg = ptr + 1;
 	} else
 		pev->group = NULL;
-	if (!is_c_func_name(*arg)) {
+	if (!pev->sdt && !is_c_func_name(*arg)) {
 ng_name:
 		semantic_error("%s is bad for event name -it must "
 			       "follow C symbol-naming rule.\n", *arg);
@@ -1642,6 +1642,7 @@ int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev)
 			ret = -ENOMEM;
 			goto out;
 		}
+		tev->uprobes = (tp->module[0] == '/');
 		p++;
 	} else
 		p = argv[1];
@@ -2516,7 +2517,7 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
 	int ret;
 
 	/* If probe_event or trace_event already have the name, reuse it */
-	if (pev->event)
+	if (pev->event && !pev->sdt)
 		event = pev->event;
 	else if (tev->event)
 		event = tev->event;
@@ -2529,7 +2530,7 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
 		else
 			event = tev->point.realname;
 	}
-	if (pev->group)
+	if (pev->group && !pev->sdt)
 		group = pev->group;
 	else if (tev->group)
 		group = tev->group;
@@ -2892,6 +2893,100 @@ errout:
 
 bool __weak arch__prefers_symtab(void) { return false; }
 
+/* Concatinate two arrays */
+static void *memcat(void *a, size_t sz_a, void *b, size_t sz_b)
+{
+	void *ret;
+
+	ret = malloc(sz_a + sz_b);
+	if (ret) {
+		memcpy(ret, a, sz_a);
+		memcpy(ret + sz_a, b, sz_b);
+	}
+	return ret;
+}
+
+static int
+concat_probe_trace_events(struct probe_trace_event **tevs, int *ntevs,
+			  struct probe_trace_event **tevs2, int ntevs2)
+{
+	struct probe_trace_event *new_tevs;
+	int ret = 0;
+
+	if (ntevs == 0) {
+		*tevs = *tevs2;
+		*ntevs = ntevs2;
+		*tevs2 = NULL;
+		return 0;
+	}
+
+	if (*ntevs + ntevs2 > probe_conf.max_probes)
+		ret = -E2BIG;
+	else {
+		/* Concatinate the array of probe_trace_event */
+		new_tevs = memcat(*tevs, (*ntevs) * sizeof(**tevs),
+				  *tevs2, ntevs2 * sizeof(**tevs2));
+		if (!new_tevs)
+			ret = -ENOMEM;
+		else {
+			free(*tevs);
+			*tevs = new_tevs;
+			*ntevs += ntevs2;
+		}
+	}
+	if (ret < 0)
+		clear_probe_trace_events(*tevs2, ntevs2);
+	zfree(tevs2);
+
+	return ret;
+}
+
+/*
+ * Try to find probe_trace_event from given probe caches. Return the number
+ * of cached events found, if an error occurs return the error.
+ */
+static int find_cached_events(struct perf_probe_event *pev,
+			      struct probe_trace_event **tevs,
+			      const char *target)
+{
+	struct probe_cache *cache;
+	struct probe_cache_entry *entry;
+	struct probe_trace_event *tmp_tevs = NULL;
+	int ntevs = 0;
+	int ret = 0;
+
+	cache = probe_cache__new(target);
+	/* Return 0 ("not found") if the target has no probe cache. */
+	if (!cache)
+		return 0;
+
+	for_each_probe_cache_entry(entry, cache) {
+		/* Skip the cache entry which has no name */
+		if (!entry->pev.event || !entry->pev.group)
+			continue;
+		if ((!pev->group || strglobmatch(entry->pev.group, pev->group)) &&
+		    strglobmatch(entry->pev.event, pev->event)) {
+			ret = probe_cache_entry__get_event(entry, &tmp_tevs);
+			if (ret > 0)
+				ret = concat_probe_trace_events(tevs, &ntevs,
+								&tmp_tevs, ret);
+			if (ret < 0)
+				break;
+		}
+	}
+	probe_cache__delete(cache);
+	if (ret < 0) {
+		clear_probe_trace_events(*tevs, ntevs);
+		zfree(tevs);
+	} else {
+		ret = ntevs;
+		if (ntevs > 0 && target && target[0] == '/')
+			pev->uprobes = true;
+	}
+
+	return ret;
+}
+
 static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
 					      struct probe_trace_event **tevs)
 {
@@ -2901,6 +2996,10 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
 	struct str_node *node;
 	int ret, i;
 
+	if (pev->sdt)
+		/* For SDT/cached events, we use special search functions */
+		return find_cached_events(pev, tevs, pev->target);
+
 	cache = probe_cache__new(pev->target);
 	if (!cache)
 		return 0;
tools/perf/util/probe-file.c +32 -6
index 39469c0..28a69b3 100644
@@ -362,13 +362,38 @@ probe_cache_entry__new(struct perf_probe_event *pev)
 	return entry;
 }
 
-/* For the kernel probe caches, pass target = NULL */
+int probe_cache_entry__get_event(struct probe_cache_entry *entry,
+				 struct probe_trace_event **tevs)
+{
+	struct probe_trace_event *tev;
+	struct str_node *node;
+	int ret, i;
+
+	ret = strlist__nr_entries(entry->tevlist);
+	if (ret > probe_conf.max_probes)
+		return -E2BIG;
+
+	*tevs = zalloc(ret * sizeof(*tev));
+	if (!*tevs)
+		return -ENOMEM;
+
+	i = 0;
+	strlist__for_each_entry(node, entry->tevlist) {
+		tev = &(*tevs)[i++];
+		ret = parse_probe_trace_command(node->s, tev);
+		if (ret < 0)
+			break;
+	}
+	return i;
+}
+
+/* For the kernel probe caches, pass target = NULL or DSO__NAME_KALLSYMS */
 static int probe_cache__open(struct probe_cache *pcache, const char *target)
 {
 	char cpath[PATH_MAX];
 	char sbuildid[SBUILD_ID_SIZE];
 	char *dir_name = NULL;
-	bool is_kallsyms = !target;
+	bool is_kallsyms = false;
 	int ret, fd;
 
 	if (target && build_id_cache__cached(target)) {
@@ -378,12 +403,13 @@ static int probe_cache__open(struct probe_cache *pcache, const char *target)
 		goto found;
 	}
 
-	if (target)
-		ret = filename__sprintf_build_id(target, sbuildid);
-	else {
+	if (!target || !strcmp(target, DSO__NAME_KALLSYMS)) {
 		target = DSO__NAME_KALLSYMS;
+		is_kallsyms = true;
 		ret = sysfs__sprintf_build_id("/", sbuildid);
-	}
+	} else
+		ret = filename__sprintf_build_id(target, sbuildid);
+
 	if (ret < 0) {
 		pr_debug("Failed to get build-id from %s.\n", target);
 		return ret;
tools/perf/util/probe-file.h +3 -0
index 837f530..9577b5c 100644
@@ -36,6 +36,9 @@ int probe_file__get_events(int fd, struct strfilter *filter,
 				  struct strlist *plist);
 int probe_file__del_strlist(int fd, struct strlist *namelist);
 
+int probe_cache_entry__get_event(struct probe_cache_entry *entry,
+				 struct probe_trace_event **tevs);
+
 struct probe_cache *probe_cache__new(const char *target);
 int probe_cache__add_entry(struct probe_cache *pcache,
 			   struct perf_probe_event *pev,
#13 lore raw

PATCH v12 12/16 perf probe: Search SDT/cached event from all probe caches

In reply to Masami Hiramatsu

Search SDT/cached event from all probe caches if user doesn't pass any binary. With this, we don't have to specify target binary for SDT and named cached events (which start with %).

E.g. without this, a target binary must be passed with -x.

 # perf probe -x /usr/lib64/libc-2.20.so -a %sdt_libc:\*

With this change, we don't need it anymore.

 # perf probe -a %sdt_libc:\*

---
Changes in v12:
- Rename strlist__for_each to strlist__for_each_entry.
Changes from v10:
- Splitted from "perf probe: Allow wildcard for cached events"

---
 tools/perf/util/probe-event.c |  105 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 86 insertions(+), 19 deletions(-)
tools/perf/util/probe-event.c +86 -19
index 2fb828f..8816643 100644
@@ -2555,41 +2555,60 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
 	return 0;
 }
 
-static int __add_probe_trace_events(struct perf_probe_event *pev,
-				     struct probe_trace_event *tevs,
-				     int ntevs, bool allow_suffix)
+static int __open_probe_file_and_namelist(bool uprobe,
+					  struct strlist **namelist)
 {
-	int i, fd, ret;
-	struct probe_trace_event *tev = NULL;
-	struct probe_cache *cache = NULL;
-	struct strlist *namelist;
+	int fd;
 
-	fd = probe_file__open(PF_FL_RW | (pev->uprobes ? PF_FL_UPROBE : 0));
+	fd = probe_file__open(PF_FL_RW | (uprobe ? PF_FL_UPROBE : 0));
 	if (fd < 0)
 		return fd;
 
 	/* Get current event names */
-	namelist = probe_file__get_namelist(fd);
-	if (!namelist) {
+	*namelist = probe_file__get_namelist(fd);
+	if (!(*namelist)) {
 		pr_debug("Failed to get current event list.\n");
-		ret = -ENOMEM;
-		goto close_out;
+		close(fd);
+		return -ENOMEM;
 	}
+	return fd;
+}
+
+static int __add_probe_trace_events(struct perf_probe_event *pev,
+				     struct probe_trace_event *tevs,
+				     int ntevs, bool allow_suffix)
+{
+	int i, fd[2] = {-1, -1}, up, ret;
+	struct probe_trace_event *tev = NULL;
+	struct probe_cache *cache = NULL;
+	struct strlist *namelist[2] = {NULL, NULL};
+
+	up = pev->uprobes ? 1 : 0;
+	fd[up] = __open_probe_file_and_namelist(up, &namelist[up]);
+	if (fd[up] < 0)
+		return fd[up];
 
 	ret = 0;
 	for (i = 0; i < ntevs; i++) {
 		tev = &tevs[i];
+		up = tev->uprobes ? 1 : 0;
+		if (fd[up] == -1) {	/* Open the kprobe/uprobe_events */
+			fd[up] = __open_probe_file_and_namelist(up,
+								&namelist[up]);
+			if (fd[up] < 0)
+				goto close_out;
+		}
 		/* Skip if the symbol is out of .text or blacklisted */
 		if (!tev->point.symbol && !pev->uprobes)
 			continue;
 
 		/* Set new name for tev (and update namelist) */
-		ret = probe_trace_event__set_name(tev, pev, namelist,
+		ret = probe_trace_event__set_name(tev, pev, namelist[up],
 						  allow_suffix);
 		if (ret < 0)
 			break;
 
-		ret = probe_file__add_event(fd, tev);
+		ret = probe_file__add_event(fd[up], tev);
 		if (ret < 0)
 			break;
 
@@ -2612,9 +2631,12 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
 		probe_cache__delete(cache);
 	}
 
-	strlist__delete(namelist);
 close_out:
-	close(fd);
+	for (up = 0; up < 2; up++) {
+		strlist__delete(namelist[up]);
+		if (fd[up] >= 0)
+			close(fd[up]);
+	}
 	return ret;
 }
 
@@ -2987,6 +3009,48 @@ static int find_cached_events(struct perf_probe_event *pev,
 	return ret;
 }
 
+/* Try to find probe_trace_event from all probe caches */
+static int find_cached_events_all(struct perf_probe_event *pev,
+				   struct probe_trace_event **tevs)
+{
+	struct probe_trace_event *tmp_tevs = NULL;
+	struct strlist *bidlist;
+	struct str_node *nd;
+	char *pathname;
+	int ntevs = 0;
+	int ret;
+
+	/* Get the buildid list of all valid caches */
+	bidlist = build_id_cache__list_all(true);
+	if (!bidlist) {
+		ret = -errno;
+		pr_debug("Failed to get buildids: %d\n", ret);
+		return ret;
+	}
+
+	ret = 0;
+	strlist__for_each_entry(nd, bidlist) {
+		pathname = build_id_cache__origname(nd->s);
+		ret = find_cached_events(pev, &tmp_tevs, pathname);
+		/* In the case of cnt == 0, we just skip it */
+		if (ret > 0)
+			ret = concat_probe_trace_events(tevs, &ntevs,
+							&tmp_tevs, ret);
+		free(pathname);
+		if (ret < 0)
+			break;
+	}
+	strlist__delete(bidlist);
+
+	if (ret < 0) {
+		clear_probe_trace_events(*tevs, ntevs);
+		zfree(tevs);
+	} else
+		ret = ntevs;
+
+	return ret;
+}
+
 static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
 					      struct probe_trace_event **tevs)
 {
@@ -2996,10 +3060,13 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
 	struct str_node *node;
 	int ret, i;
 
-	if (pev->sdt)
+	if (pev->sdt) {
 		/* For SDT/cached events, we use special search functions */
-		return find_cached_events(pev, tevs, pev->target);
-
+		if (!pev->target)
+			return find_cached_events_all(pev, tevs);
+		else
+			return find_cached_events(pev, tevs, pev->target);
+	}
 	cache = probe_cache__new(pev->target);
 	if (!cache)
 		return 0;
#14 lore raw

PATCH v12 13/16 perf probe: Support @BUILDID or @FILE suffix for SDT events

In reply to Masami Hiramatsu

Support @BUILDID or @FILE suffix for SDT events. This allows perf to add probes on SDTs/pre-cached events on given FILE or the file which has given BUILDID (also, this complements BUILDID.)
For example, both gcc and libstdc++ has same SDTs as below. If you would like to add a probe on sdt_libstdcxx:catch on gcc, you can do as below.

----

  # perf list sdt | tail -n 6
    sdt_libstdcxx:catch@/usr/bin/gcc(0cc207fc4b27)     [SDT event]
    sdt_libstdcxx:catch@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)
    sdt_libstdcxx:rethrow@/usr/bin/gcc(0cc207fc4b27)   [SDT event]
    sdt_libstdcxx:rethrow@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)
    sdt_libstdcxx:throw@/usr/bin/gcc(0cc207fc4b27)     [SDT event]
    sdt_libstdcxx:throw@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)
  # perf probe -a %sdt_libstdcxx:catch@0cc
  Added new event:
    sdt_libstdcxx:catch  (on %catch in /usr/bin/gcc)

You can now use it in all perf tools, such as:

perf record -e sdt_libstdcxx:catch -aR sleep 1
----

---
Changes in v12:
- Rename strlist__for_each to strlist__for_each_entry.

---
 tools/perf/util/build-id.c    |   43 +++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/build-id.h    |    1 +
 tools/perf/util/probe-event.c |   17 ++++++++++++++--
 3 files changed, 59 insertions(+), 2 deletions(-)
tools/perf/util/build-id.c +43 -0
index 8e86a83..e59003e 100644
@@ -523,6 +523,49 @@ err_out:
 	goto out_free;
 }
 
+static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
+{
+	size_t i;
+
+	for (i = 0; i < len; i++) {
+		if (!isxdigit(maybe_sbuild_id[i]))
+			return false;
+	}
+	return true;
+}
+
+/* Return the valid complete build-id */
+char *build_id_cache__complement(const char *incomplete_sbuild_id)
+{
+	struct strlist *bidlist;
+	struct str_node *nd, *cand = NULL;
+	char *sbuild_id = NULL;
+	size_t len = strlen(incomplete_sbuild_id);
+
+	if (len >= SBUILD_ID_SIZE ||
+	    !str_is_build_id(incomplete_sbuild_id, len))
+		return NULL;
+
+	bidlist = build_id_cache__list_all(true);
+	if (!bidlist)
+		return NULL;
+
+	strlist__for_each_entry(nd, bidlist) {
+		if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
+			continue;
+		if (cand) {	/* Error: There are more than 2 candidates. */
+			cand = NULL;
+			break;
+		}
+		cand = nd;
+	}
+	if (cand)
+		sbuild_id = strdup(cand->s);
+	strlist__delete(bidlist);
+
+	return sbuild_id;
+}
+
 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 			       bool is_kallsyms, bool is_vdso)
 {
tools/perf/util/build-id.h +1 -0
index 64e740f..d279906 100644
@@ -35,6 +35,7 @@ char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size);
 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 			       bool is_kallsyms, bool is_vdso);
 struct strlist *build_id_cache__list_all(bool validonly);
+char *build_id_cache__complement(const char *incomplete_sbuild_id);
 int build_id_cache__list_build_ids(const char *pathname,
 				   struct strlist **result);
 bool build_id_cache__cached(const char *sbuild_id);
tools/perf/util/probe-event.c +15 -2
index 8816643..b38548c 100644
@@ -1251,8 +1251,21 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 	ptr = strpbrk(arg, ";=@+%");
 	if (pev->sdt) {
 		if (ptr) {
-			semantic_error("%s must contain only an SDT event name.\n", arg);
-			return -EINVAL;
+			if (*ptr != '@') {
+				semantic_error("%s must be an SDT name.\n",
+					       arg);
+				return -EINVAL;
+			}
+			/* This must be a target file name or build id */
+			tmp = build_id_cache__complement(ptr + 1);
+			if (tmp) {
+				pev->target = build_id_cache__origname(tmp);
+				free(tmp);
+			} else
+				pev->target = strdup(ptr + 1);
+			if (!pev->target)
+				return -ENOMEM;
+			*ptr = '\0';
 		}
 		ret = parse_perf_probe_event_name(&arg, pev);
 		if (ret == 0) {
#15 lore raw

PATCH v12 14/16 perf probe: Support a special SDT probe format

In reply to Masami Hiramatsu

Support a special SDT probe format which can omit the '%' prefix only if the SDT group name starts with "sdt_". So, for example both of "%sdt_libc:setjump" and "sdt_libc:setjump" are acceptable for perf probe --add.

E.g. without this:
----

  # perf probe -a sdt_libc:setjmp
  Semantic error :There is non-digit char in line number.
  ...
  ----
With this:
  ----
  # perf probe -a sdt_libc:setjmp
  Added new event:
    sdt_libc:setjmp      (on %setjmp in /usr/lib64/libc-2.20.so)

You can now use it in all perf tools, such as:

perf record -e sdt_libc:setjmp -aR sleep 1
----

---
 tools/perf/Documentation/perf-probe.txt |    4 +++-
 tools/perf/util/probe-event.c           |   12 ++++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)
tools/perf/Documentation/perf-probe.txt +3 -1
index 39e3870..736da44 100644
@@ -152,7 +152,9 @@ Probe points are defined by following syntax.
      [[GROUP:]EVENT=]SRC;PTN [ARG ...]
 
     4) Pre-defined SDT events or cached event with name
-     %[PROVIDER:]SDTEVENT
+     %[sdt_PROVIDER:]SDTEVENT
+     or,
+     sdt_PROVIDER:SDTEVENT
 
 'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function. You can also specify a group name by 'GROUP', if omitted, set 'probe' is used for kprobe and 'probe_<bin>' is used for uprobe.
 Note that using existing group name can conflict with other events. Especially, using the group name reserved for kernel modules can hide embedded events in the
tools/perf/util/probe-event.c +10 -2
index b38548c..8b4fb63 100644
@@ -1243,9 +1243,17 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 	if (!arg)
 		return -EINVAL;
 
-	if (arg[0] == '%') {
+	/*
+	 * If the probe point starts with '%',
+	 * or starts with "sdt_" and has a ':' but no '=',
+	 * then it should be a SDT/cached probe point.
+	 */
+	if (arg[0] == '%' ||
+	    (!strncmp(arg, "sdt_", 4) &&
+	     !!strchr(arg, ':') && !strchr(arg, '='))) {
 		pev->sdt = true;
-		arg++;
+		if (arg[0] == '%')
+			arg++;
 	}
 
 	ptr = strpbrk(arg, ";=@+%");
#16 lore raw

PATCH v12 15/16 perf build: Add sdt feature detection

In reply to Masami Hiramatsu

This checks whether sys/sdt.h is available or not, which is required for DTRACE_PROBE().
We can disable this feature by passing NO_SDT=1 when building.
This flag will be used for SDT test case and further SDT events in perftools.

---
 tools/perf/Makefile.perf   |    3 +++
 tools/perf/config/Makefile |   10 ++++++++++
 tools/perf/tests/make      |    3 ++-
 3 files changed, 15 insertions(+), 1 deletion(-)
tools/build/Makefile.feature +2 -1
index 57c8f98..6bc7767 100644
@@ -60,7 +60,8 @@ FEATURE_TESTS_BASIC :=			\
 	zlib				\
 	lzma				\
 	get_cpuid			\
-	bpf
+	bpf				\
+	sdt
 
 # FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA is the complete list
 # of all feature tests
tools/build/feature/Makefile +5 -1
index 3d88f09..82d357f 100644
@@ -43,7 +43,8 @@ FILES=					\
 	test-zlib.bin			\
 	test-lzma.bin			\
 	test-bpf.bin			\
-	test-get_cpuid.bin
+	test-get_cpuid.bin		\
+	test-sdt.bin
 
 FILES := $(addprefix $(OUTPUT),$(FILES))
 
@@ -205,6 +206,9 @@ $(OUTPUT)test-get_cpuid.bin:
 $(OUTPUT)test-bpf.bin:
 	$(BUILD)
 
+$(OUTPUT)test-sdt.bin:
+	$(BUILD)
+
 -include $(OUTPUT)*.d
 
 ###############################
tools/build/feature/test-all.c +5 -0
index a282e8c..f538c5f 100644
@@ -137,6 +137,10 @@
 # include "test-libcrypto.c"
 #undef main
 
+#define main main_test_sdt
+# include "test-sdt.c"
+#undef main
+
 int main(int argc, char *argv[])
 {
 	main_test_libpython();
@@ -168,6 +172,7 @@ int main(int argc, char *argv[])
 	main_test_get_cpuid();
 	main_test_bpf();
 	main_test_libcrypto();
+	main_test_sdt();
 
 	return 0;
 }
tools/build/feature/test-sdt.c new file +7 -0
new file mode 100644
index 0000000..e4531a6
@@ -0,0 +1,7 @@
+#include <sys/sdt.h>
+
+int main(void)
+{
+	DTRACE_PROBE(provider, name);
+	return 0;
+}
tools/perf/Makefile.perf +3 -0
index d0a2cb1..458eaf5 100644
@@ -81,6 +81,9 @@ include ../scripts/utilities.mak
 #
 # Define NO_LIBBPF if you do not want BPF support
 #
+# Define NO_SDT if you do not want to define SDT event in perf tools,
+# note that it doesn't disable SDT scanning support.
+#
 # Define FEATURES_DUMP to provide features detection dump file
 # and bypass the feature detection
 
tools/perf/config/Makefile +10 -0
index 534c811..4334b7d 100644
@@ -345,6 +345,16 @@ ifndef NO_LIBELF
   endif # NO_LIBBPF
 endif # NO_LIBELF
 
+ifndef NO_SDT
+  ifneq ($(feature-sdt), 1)
+    msg := $(warning No sys/sdt.h found, no SDT events are defined, please install systemtap-sdt-devel or systemtap-sdt-dev);
+    NO_SDT := 1;
+  else
+    CFLAGS += -DHAVE_SDT_EVENT
+    $(call detected,CONFIG_SDT_EVENT)
+  endif
+endif
+
 ifdef PERF_HAVE_JITDUMP
   ifndef NO_DWARF
     $(call detected,CONFIG_JITDUMP)
tools/perf/tests/make +2 -1
index cac15d9..ac801be 100644
@@ -81,6 +81,7 @@ make_no_libbionic   := NO_LIBBIONIC=1
 make_no_auxtrace    := NO_AUXTRACE=1
 make_no_libbpf	    := NO_LIBBPF=1
 make_no_libcrypto   := NO_LIBCRYPTO=1
+make_no_sdt	    := NO_SDT=1
 make_tags           := tags
 make_cscope         := cscope
 make_help           := help
@@ -104,7 +105,7 @@ make_minimal        := NO_LIBPERL=1 NO_LIBPYTHON=1 NO_NEWT=1 NO_GTK2=1
 make_minimal        += NO_DEMANGLE=1 NO_LIBELF=1 NO_LIBUNWIND=1 NO_BACKTRACE=1
 make_minimal        += NO_LIBNUMA=1 NO_LIBAUDIT=1 NO_LIBBIONIC=1
 make_minimal        += NO_LIBDW_DWARF_UNWIND=1 NO_AUXTRACE=1 NO_LIBBPF=1
-make_minimal        += NO_LIBCRYPTO=1
+make_minimal        += NO_LIBCRYPTO=1 NO_SDT=1
 
 # $(run) contains all available tests
 run := make_pure
#17 lore raw

PATCH v12 16/16 perf-test: Add a test case for SDT event

In reply to Masami Hiramatsu

Add a basic test case for SDT event support.
This test scans an SDT event in perftools and
check whether the SDT event is correctly stored
into the buildid cache.
Here is an example:
----

  $ perf test sdt -v
  46: Test SDT event probing                                   :
  --- start ---
  test child forked, pid 20732
  Found 72 SDTs in /home/mhiramat/ksrc/linux/tools/perf/perf
  Writing cache: %sdt_perf:test_target=test_target
  Cache committed: 0
  symbol:test_target file:(null) line:0 offset:0 return:0 lazy:(null)
  test child finished with 0
  ---- end ----
  Test SDT event probing: Ok
  ----
---
 tools/perf/tests/Build          |    1 
 tools/perf/tests/builtin-test.c |    4 +
 tools/perf/tests/sdt.c          |  115 +++++++++++++++++++++++++++++++++++++++
 tools/perf/tests/tests.h        |    1 
 4 files changed, 121 insertions(+)
 create mode 100644 tools/perf/tests/sdt.c
tools/perf/tests/Build +1 -0
index 66a2898..4158422 100644
@@ -39,6 +39,7 @@ perf-y += stat.o
 perf-y += event_update.o
 perf-y += event-times.o
 perf-y += backward-ring-buffer.o
+perf-y += sdt.o
 
 $(OUTPUT)tests/llvm-src-base.c: tests/bpf-script-example.c tests/Build
 	$(call rule_mkdir)
tools/perf/tests/builtin-test.c +4 -0
index 0e95c20..c0e0ccb 100644
@@ -212,6 +212,10 @@ static struct test generic_tests[] = {
 		.func = test__backward_ring_buffer,
 	},
 	{
+		.desc = "Test SDT event probing",
+		.func = test__sdt_event,
+	},
+	{
 		.func = NULL,
 	},
 };
tools/perf/tests/sdt.c new file +115 -0

115 lines not on this page · raw message

tools/perf/tests/tests.h +1 -0
index c57e72c..93cfb0b 100644
@@ -87,6 +87,7 @@ int test__synthesize_stat_round(int subtest);
 int test__event_update(int subtest);
 int test__event_times(int subtest);
 int test__backward_ring_buffer(int subtest);
+int test__sdt_event(int subtest);
 
 #if defined(__arm__) || defined(__aarch64__)
 #ifdef HAVE_DWARF_UNWIND_SUPPORT
#18 lore raw
In reply to Masami Hiramatsu
Quoted 10 lines · Masami Hiramatsu

Hi,

Here is the 12th version of the patchset for probe-cache and initial SDT support.

Here is the previous v11: https://lkml.org/lkml/2016/6/14/1041

In this version I just rename strlist__for_each to strlist__for_each_entry, and change some patch description.

I tested it on Node.js (and applied to acme's perf/core), and it works. Thanks!

# perf script
            node 36750 [006]  3080.761533:
sdt_node:http__server__request: (da8b0c)
            node 36750 [006]  3081.368771:
sdt_node:http__server__request: (da8b0c)
            node 36750 [006]  3081.592925:
sdt_node:http__server__request: (da8b0c)
            node 36750 [006]  3081.976802:
sdt_node:http__server__request: (da8b0c)
            node 36750 [006]  3082.296709:
sdt_node:http__server__request: (da8b0c)

Since it doesn't set the is-enabled semaphore yet, I had to do that manually for the probes that use it. I know that will be a latter addition.

# perf list | grep sdt
  sdt_node:http__client__request                     [Tracepoint event]
  sdt_node:http__server__request                     [Tracepoint event]
  sdt_node:gc__done                                  [SDT event]
  sdt_node:gc__start                                 [SDT event]
  sdt_node:http__client__request                     [SDT event]
  sdt_node:http__client__response                    [SDT event]
  sdt_node:http__server__request                     [SDT event]
  sdt_node:http__server__response                    [SDT event]
  sdt_node:net__server__connection                   [SDT event]
  sdt_node:net__stream__end                          [SDT event]

It's also a bit weird to see these listed twice, but I understand what's happening. If this continues to prove confusing, I guess later on we could change it to exclude listing SDT events that have been promoted to Tracepoint events, or not list SDT events in "perf list" at all, leaving them for "perf probe --cache --list".

Anyway, this is great as is, and thanks again.

Brendan

Quoted 51 lines

Thank you,

---

Hemant Kumar (1):
perf/sdt: ELF support for SDT

Masami Hiramatsu (15):
perf probe: Use cache entry if possible
perf probe: Show all cached probes
perf probe: Remove caches when --cache is given
perf probe: Add group name support
perf buildid-cache: Scan and import user SDT events to probe cache perf probe: Accept %sdt and %cached event name
perf-list: Show SDT and pre-cached events
perf-list: Skip SDTs placed in invalid binaries
perf: probe-cache: Add for_each_probe_cache_entry() wrapper perf probe: Allow wildcard for cached events
perf probe: Search SDT/cached event from all probe caches perf probe: Support @BUILDID or @FILE suffix for SDT events perf probe: Support a special SDT probe format
perf build: Add sdt feature detection
perf-test: Add a test case for SDT event

 tools/perf/Documentation/perf-buildid-cache.txt |    3
 tools/perf/Documentation/perf-probe.txt         |   30 +-
 tools/perf/Makefile.perf                        |    3
 tools/perf/builtin-list.c                       |    6
 tools/perf/builtin-probe.c                      |   31 ++
 tools/perf/config/Makefile                      |   10 +
 tools/perf/tests/Build                          |    1
 tools/perf/tests/builtin-test.c                 |    4
 tools/perf/tests/make                           |    3
 tools/perf/tests/sdt.c                          |  115 +++++++
 tools/perf/tests/tests.h                        |    1
 tools/perf/util/build-id.c                      |  212 +++++++++++++
 tools/perf/util/build-id.h                      |    4
 tools/perf/util/parse-events.c                  |   82 +++++
 tools/perf/util/parse-events.h                  |    2
 tools/perf/util/probe-event.c                   |  366 +++++++++++++++++++++--
 tools/perf/util/probe-event.h                   |    1
 tools/perf/util/probe-file.c                    |  226 +++++++++++++-
 tools/perf/util/probe-file.h                    |   24 +-
 tools/perf/util/symbol-elf.c                    |  252 ++++++++++++++++
 tools/perf/util/symbol.h                        |   22 +
 21 files changed, 1333 insertions(+), 65 deletions(-)
 create mode 100644 tools/perf/tests/sdt.c

--
Masami Hiramatsu

#19 lore raw
Quoted 26 lines · On Fri, 24 Jun 2016 13:25:20 -0700 Brendan Gregg <[email protected]>…
Quoted 10 lines · Masami Hiramatsu

Hi,

Here is the 12th version of the patchset for probe-cache and initial SDT support.

Here is the previous v11: https://lkml.org/lkml/2016/6/14/1041

In this version I just rename strlist__for_each to strlist__for_each_entry, and change some patch description.

I tested it on Node.js (and applied to acme's perf/core), and it works. Thanks!

# perf script
            node 36750 [006]  3080.761533:
sdt_node:http__server__request: (da8b0c)
            node 36750 [006]  3081.368771:
sdt_node:http__server__request: (da8b0c)
            node 36750 [006]  3081.592925:
sdt_node:http__server__request: (da8b0c)
            node 36750 [006]  3081.976802:
sdt_node:http__server__request: (da8b0c)
            node 36750 [006]  3082.296709:
sdt_node:http__server__request: (da8b0c)
Quoted 3 lines

Since it doesn't set the is-enabled semaphore yet, I had to do that manually for the probes that use it. I know that will be a latter addition.

Yes, I'd like to support it. However, the question is who should enable it.

To enable it from perf, perf must attach the target running processes and change the semaphore. If we run "perf record -a", it has to check all the running process and tweak it. Moreover, it may have to hook the execve syscall.

To enable it from kernel, hooking the target process is easier, since we already did it in uprobes. However, it means we'll introduce a special functionality to tweak user binary, and of course it may need to understand SDT section to find out the semaphore.

So, one possible solution is, adding a semaphore option(like an address) to uprobe events and enable it via ftrace. On this way, perf just analyzes SDT and pass the semaphore address to ftrace when defining a probe, and ftrace set 1 to the semaphre address.

Quoted 13 lines
# perf list | grep sdt
  sdt_node:http__client__request                     [Tracepoint event]
  sdt_node:http__server__request                     [Tracepoint event]
  sdt_node:gc__done                                  [SDT event]
  sdt_node:gc__start                                 [SDT event]
  sdt_node:http__client__request                     [SDT event]
  sdt_node:http__client__response                    [SDT event]
  sdt_node:http__server__request                     [SDT event]
  sdt_node:http__server__response                    [SDT event]
  sdt_node:net__server__connection                   [SDT event]
  sdt_node:net__stream__end                          [SDT event]
Quoted 5 lines

It's also a bit weird to see these listed twice, but I understand what's happening. If this continues to prove confusing, I guess later on we could change it to exclude listing SDT events that have been promoted to Tracepoint events, or not list SDT events in "perf list" at all, leaving them for "perf probe --cache --list".

Ah, right. Hmm, at this point, I'd like latter method, since perf record doesn't support SDT directly yet. So we just need to drop 08/16 and 09/16. It should be implemented with perf-record support.

Thank you!

Quoted 57 lines

Anyway, this is great as is, and thanks again.

Brendan

Quoted 51 lines

Thank you,

---

Hemant Kumar (1):
perf/sdt: ELF support for SDT

Masami Hiramatsu (15):
perf probe: Use cache entry if possible
perf probe: Show all cached probes
perf probe: Remove caches when --cache is given
perf probe: Add group name support
perf buildid-cache: Scan and import user SDT events to probe cache perf probe: Accept %sdt and %cached event name
perf-list: Show SDT and pre-cached events
perf-list: Skip SDTs placed in invalid binaries
perf: probe-cache: Add for_each_probe_cache_entry() wrapper perf probe: Allow wildcard for cached events
perf probe: Search SDT/cached event from all probe caches perf probe: Support @BUILDID or @FILE suffix for SDT events perf probe: Support a special SDT probe format
perf build: Add sdt feature detection
perf-test: Add a test case for SDT event

 tools/perf/Documentation/perf-buildid-cache.txt |    3
 tools/perf/Documentation/perf-probe.txt         |   30 +-
 tools/perf/Makefile.perf                        |    3
 tools/perf/builtin-list.c                       |    6
 tools/perf/builtin-probe.c                      |   31 ++
 tools/perf/config/Makefile                      |   10 +
 tools/perf/tests/Build                          |    1
 tools/perf/tests/builtin-test.c                 |    4
 tools/perf/tests/make                           |    3
 tools/perf/tests/sdt.c                          |  115 +++++++
 tools/perf/tests/tests.h                        |    1
 tools/perf/util/build-id.c                      |  212 +++++++++++++
 tools/perf/util/build-id.h                      |    4
 tools/perf/util/parse-events.c                  |   82 +++++
 tools/perf/util/parse-events.h                  |    2
 tools/perf/util/probe-event.c                   |  366 +++++++++++++++++++++--
 tools/perf/util/probe-event.h                   |    1
 tools/perf/util/probe-file.c                    |  226 +++++++++++++-
 tools/perf/util/probe-file.h                    |   24 +-
 tools/perf/util/symbol-elf.c                    |  252 ++++++++++++++++
 tools/perf/util/symbol.h                        |   22 +
 21 files changed, 1333 insertions(+), 65 deletions(-)
 create mode 100644 tools/perf/tests/sdt.c

--
Masami Hiramatsu

Signature · 1 line
Masami Hiramatsu <[email protected]>