[v2,2/2] perf stat: Support regex pattern in --for-each-cgroup
diff mbox series

Message ID 20201024025918.453431-2-namhyung@kernel.org
State New, archived
Headers show
Series
  • [1/2] perf test: Use generic event for expand_libpfm_events()
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Commit Message

Namhyung Kim Oct. 24, 2020, 2:59 a.m. UTC
To make the command line even more compact with cgroups, support regex
pattern matching in cgroup names.

  $ perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1

          3,000.73 msec cpu-clock                 foo #    2.998 CPUs utilized
    12,530,992,699      cycles                    foo #    7.517 GHz                      (100.00%)
          1,000.61 msec cpu-clock                 foo/bar #    1.000 CPUs utilized
     4,178,529,579      cycles                    foo/bar #    2.506 GHz                      (100.00%)
          1,000.03 msec cpu-clock                 foo/baz #    0.999 CPUs utilized
     4,176,104,315      cycles                    foo/baz #    2.505 GHz                      (100.00%)

       1.000892614 seconds time elapsed

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/Documentation/perf-stat.txt |   5 +-
 tools/perf/util/cgroup.c               | 192 +++++++++++++++++++++----
 2 files changed, 171 insertions(+), 26 deletions(-)

Comments

Jiri Olsa Oct. 26, 2020, 11:40 a.m. UTC | #1
On Sat, Oct 24, 2020 at 11:59:18AM +0900, Namhyung Kim wrote:
> To make the command line even more compact with cgroups, support regex
> pattern matching in cgroup names.
> 
>   $ perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1
> 
>           3,000.73 msec cpu-clock                 foo #    2.998 CPUs utilized
>     12,530,992,699      cycles                    foo #    7.517 GHz                      (100.00%)
>           1,000.61 msec cpu-clock                 foo/bar #    1.000 CPUs utilized
>      4,178,529,579      cycles                    foo/bar #    2.506 GHz                      (100.00%)
>           1,000.03 msec cpu-clock                 foo/baz #    0.999 CPUs utilized
>      4,176,104,315      cycles                    foo/baz #    2.505 GHz                      (100.00%)

just curious.. there was another foo/XXX group using the
rest of the cycles, right?


also perhaps we want to warn if there's no match found:

	$ sudo ./perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1

	 Performance counter stats for 'system wide':


	       1.002375575 seconds time elapsed

jirka
Namhyung Kim Oct. 26, 2020, 12:32 p.m. UTC | #2
Hi Jiri,

On Mon, Oct 26, 2020 at 8:40 PM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Sat, Oct 24, 2020 at 11:59:18AM +0900, Namhyung Kim wrote:
> > To make the command line even more compact with cgroups, support regex
> > pattern matching in cgroup names.
> >
> >   $ perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1
> >
> >           3,000.73 msec cpu-clock                 foo #    2.998 CPUs utilized
> >     12,530,992,699      cycles                    foo #    7.517 GHz                      (100.00%)
> >           1,000.61 msec cpu-clock                 foo/bar #    1.000 CPUs utilized
> >      4,178,529,579      cycles                    foo/bar #    2.506 GHz                      (100.00%)
> >           1,000.03 msec cpu-clock                 foo/baz #    0.999 CPUs utilized
> >      4,176,104,315      cycles                    foo/baz #    2.505 GHz                      (100.00%)
>
> just curious.. there was another foo/XXX group using the
> rest of the cycles, right?

No, if so it should be displayed too.  But actually there was a process
in the foo cgroup itself.

>
> also perhaps we want to warn if there's no match found:
>
>         $ sudo ./perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1
>
>          Performance counter stats for 'system wide':
>
>
>                1.002375575 seconds time elapsed
>

Right, will check this case.

Thanks
Namhyung
Jiri Olsa Oct. 26, 2020, 1:12 p.m. UTC | #3
On Mon, Oct 26, 2020 at 09:32:34PM +0900, Namhyung Kim wrote:
> Hi Jiri,
> 
> On Mon, Oct 26, 2020 at 8:40 PM Jiri Olsa <jolsa@redhat.com> wrote:
> >
> > On Sat, Oct 24, 2020 at 11:59:18AM +0900, Namhyung Kim wrote:
> > > To make the command line even more compact with cgroups, support regex
> > > pattern matching in cgroup names.
> > >
> > >   $ perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1
> > >
> > >           3,000.73 msec cpu-clock                 foo #    2.998 CPUs utilized
> > >     12,530,992,699      cycles                    foo #    7.517 GHz                      (100.00%)
> > >           1,000.61 msec cpu-clock                 foo/bar #    1.000 CPUs utilized
> > >      4,178,529,579      cycles                    foo/bar #    2.506 GHz                      (100.00%)
> > >           1,000.03 msec cpu-clock                 foo/baz #    0.999 CPUs utilized
> > >      4,176,104,315      cycles                    foo/baz #    2.505 GHz                      (100.00%)
> >
> > just curious.. there was another foo/XXX group using the
> > rest of the cycles, right?
> 
> No, if so it should be displayed too.  But actually there was a process
> in the foo cgroup itself.

nah, right ;-) ok

jirka

> 
> >
> > also perhaps we want to warn if there's no match found:
> >
> >         $ sudo ./perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1
> >
> >          Performance counter stats for 'system wide':
> >
> >
> >                1.002375575 seconds time elapsed
> >
> 
> Right, will check this case.
> 
> Thanks
> Namhyung
>
Arnaldo Carvalho de Melo Oct. 26, 2020, 5:53 p.m. UTC | #4
Em Mon, Oct 26, 2020 at 09:32:34PM +0900, Namhyung Kim escreveu:
> Hi Jiri,
> 
> On Mon, Oct 26, 2020 at 8:40 PM Jiri Olsa <jolsa@redhat.com> wrote:
> >
> > On Sat, Oct 24, 2020 at 11:59:18AM +0900, Namhyung Kim wrote:
> > > To make the command line even more compact with cgroups, support regex
> > > pattern matching in cgroup names.
> > >
> > >   $ perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1
> > >
> > >           3,000.73 msec cpu-clock                 foo #    2.998 CPUs utilized
> > >     12,530,992,699      cycles                    foo #    7.517 GHz                      (100.00%)
> > >           1,000.61 msec cpu-clock                 foo/bar #    1.000 CPUs utilized
> > >      4,178,529,579      cycles                    foo/bar #    2.506 GHz                      (100.00%)
> > >           1,000.03 msec cpu-clock                 foo/baz #    0.999 CPUs utilized
> > >      4,176,104,315      cycles                    foo/baz #    2.505 GHz                      (100.00%)
> >
> > just curious.. there was another foo/XXX group using the
> > rest of the cycles, right?
> 
> No, if so it should be displayed too.  But actually there was a process
> in the foo cgroup itself.
> 
> >
> > also perhaps we want to warn if there's no match found:
> >
> >         $ sudo ./perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1
> >
> >          Performance counter stats for 'system wide':
> >
> >
> >                1.002375575 seconds time elapsed
> >
> 
> Right, will check this case.

Hum, I thought that could be done on top of this one, but then, the
ambiguity of:

1. No samples for a cgroups matching that expression

2. No cgroups match that expression

Is real and warrants a warning for the 'no cgroups match the
--for-each-group regexp' case.

So I'll wait for v3 with that warning,

Thanks,

- Arnaldo
Namhyung Kim Oct. 27, 2020, 5 a.m. UTC | #5
Hi Arnaldo,

On Tue, Oct 27, 2020 at 2:53 AM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> Em Mon, Oct 26, 2020 at 09:32:34PM +0900, Namhyung Kim escreveu:
> > Hi Jiri,
> >
> > On Mon, Oct 26, 2020 at 8:40 PM Jiri Olsa <jolsa@redhat.com> wrote:
> > > also perhaps we want to warn if there's no match found:
> > >
> > >         $ sudo ./perf stat -a -e cpu-clock,cycles --for-each-cgroup ^foo sleep 1
> > >
> > >          Performance counter stats for 'system wide':
> > >
> > >
> > >                1.002375575 seconds time elapsed
> > >
> >
> > Right, will check this case.
>
> Hum, I thought that could be done on top of this one, but then, the
> ambiguity of:
>
> 1. No samples for a cgroups matching that expression
>
> 2. No cgroups match that expression
>
> Is real and warrants a warning for the 'no cgroups match the
> --for-each-group regexp' case.

The 1 will be handled by perf stat showing <not counted> and
I'll add a warning for the item 2 like below:

  # perf stat -a -e cycles --for-each-cgroup ^foo sleep 1
  no cgroup matched: ^foo

   Usage: perf stat [<options>] [<command>]

        --for-each-cgroup <name>
                          expand events for each cgroup

Thanks
Namhyung

Patch
diff mbox series

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 9f9f29025e49..2b44c08b3b23 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -168,8 +168,9 @@  command line can be used: 'perf stat -e cycles -G cgroup_name -a -e cycles'.
 
 --for-each-cgroup name::
 Expand event list for each cgroup in "name" (allow multiple cgroups separated
-by comma).  This has same effect that repeating -e option and -G option for
-each event x name.  This option cannot be used with -G/--cgroup option.
+by comma).  It also support regex patterns to match multiple groups.  This has same
+effect that repeating -e option and -G option for each event x name.  This option
+cannot be used with -G/--cgroup option.
 
 -o file::
 --output file::
diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
index b81324a13a2b..127c2411fb9f 100644
--- a/tools/perf/util/cgroup.c
+++ b/tools/perf/util/cgroup.c
@@ -13,9 +13,19 @@ 
 #include <stdlib.h>
 #include <string.h>
 #include <api/fs/fs.h>
+#include <ftw.h>
+#include <regex.h>
 
 int nr_cgroups;
 
+/* used to match cgroup name with patterns */
+struct cgroup_name {
+	struct list_head list;
+	bool used;
+	char name[];
+};
+static LIST_HEAD(cgroup_list);
+
 static int open_cgroup(const char *name)
 {
 	char path[PATH_MAX + 1];
@@ -149,6 +159,137 @@  void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
 		evsel__set_default_cgroup(evsel, cgroup);
 }
 
+/* helper function for ftw() in match_cgroups and list_cgroups */
+static int add_cgroup_name(const char *fpath, const struct stat *sb __maybe_unused,
+			   int typeflag)
+{
+	struct cgroup_name *cn;
+
+	if (typeflag != FTW_D)
+		return 0;
+
+	cn = malloc(sizeof(*cn) + strlen(fpath) + 1);
+	if (cn == NULL)
+		return -1;
+
+	cn->used = false;
+	strcpy(cn->name, fpath);
+
+	list_add_tail(&cn->list, &cgroup_list);
+	return 0;
+}
+
+static void release_cgroup_list(void)
+{
+	struct cgroup_name *cn;
+
+	while (!list_empty(&cgroup_list)) {
+		cn = list_first_entry(&cgroup_list, struct cgroup_name, list);
+		list_del(&cn->list);
+		free(cn);
+	}
+}
+
+/* collect given cgroups only */
+static int list_cgroups(const char *str)
+{
+	const char *p, *e, *eos = str + strlen(str);
+	struct cgroup_name *cn;
+	char *s;
+
+	/* use given name as is - for testing purpose */
+	for (;;) {
+		p = strchr(str, ',');
+		e = p ? p : eos;
+
+		if (e - str) {
+			int ret;
+
+			s = strndup(str, e - str);
+			if (!s)
+				return -1;
+			/* pretend if it's added by ftw() */
+			ret = add_cgroup_name(s, NULL, FTW_D);
+			free(s);
+			if (ret)
+				return -1;
+		} else {
+			if (add_cgroup_name("", NULL, FTW_D) < 0)
+				return -1;
+		}
+
+		if (!p)
+			break;
+		str = p+1;
+	}
+
+	/* these groups will be used */
+	list_for_each_entry(cn, &cgroup_list, list)
+		cn->used = true;
+
+	return 0;
+}
+
+/* collect all cgroups first and then match with the pattern */
+static int match_cgroups(const char *str)
+{
+	char mnt[PATH_MAX];
+	const char *p, *e, *eos = str + strlen(str);
+	struct cgroup_name *cn;
+	regex_t reg;
+	int prefix_len;
+	char *s;
+
+	if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event"))
+		return -1;
+
+	/* cgroup_name will have a full path, skip the root directory */
+	prefix_len = strlen(mnt);
+
+	/* collect all cgroups in the cgroup_list */
+	if (ftw(mnt, add_cgroup_name, 20) < 0)
+		return -1;
+
+	for (;;) {
+		p = strchr(str, ',');
+		e = p ? p : eos;
+
+		/* allow empty cgroups, i.e., skip */
+		if (e - str) {
+			/* termination added */
+			s = strndup(str, e - str);
+			if (!s)
+				return -1;
+			if (regcomp(&reg, s, REG_NOSUB)) {
+				free(s);
+				return -1;
+			}
+
+			/* check cgroup name with the pattern */
+			list_for_each_entry(cn, &cgroup_list, list) {
+				char *name = cn->name + prefix_len;
+
+				if (name[0] == '/' && name[1])
+					name++;
+				if (!regexec(&reg, name, 0, NULL, 0))
+					cn->used = true;
+			}
+			regfree(&reg);
+			free(s);
+		} else {
+			/* first entry to root cgroup */
+			cn = list_first_entry(&cgroup_list, struct cgroup_name,
+					      list);
+			cn->used = true;
+		}
+
+		if (!p)
+			break;
+		str = p+1;
+	}
+	return prefix_len;
+}
+
 int parse_cgroups(const struct option *opt, const char *str,
 		  int unset __maybe_unused)
 {
@@ -201,6 +342,11 @@  int parse_cgroups(const struct option *opt, const char *str,
 	return 0;
 }
 
+static bool has_pattern_string(const char *str)
+{
+	return !!strpbrk(str, "{}[]()|*+?^$");
+}
+
 int evlist__expand_cgroup(struct evlist *evlist, const char *str,
 			  struct rblist *metric_events, bool open_cgroup)
 {
@@ -208,8 +354,9 @@  int evlist__expand_cgroup(struct evlist *evlist, const char *str,
 	struct evsel *pos, *evsel, *leader;
 	struct rblist orig_metric_events;
 	struct cgroup *cgrp = NULL;
-	const char *p, *e, *eos = str + strlen(str);
+	struct cgroup_name *cn;
 	int ret = -1;
+	int prefix_len;
 
 	if (evlist->core.nr_entries == 0) {
 		fprintf(stderr, "must define events before cgroups\n");
@@ -234,24 +381,25 @@  int evlist__expand_cgroup(struct evlist *evlist, const char *str,
 		rblist__init(&orig_metric_events);
 	}
 
-	for (;;) {
-		p = strchr(str, ',');
-		e = p ? p : eos;
+	if (has_pattern_string(str))
+		prefix_len = match_cgroups(str);
+	else
+		prefix_len = list_cgroups(str);
 
-		/* allow empty cgroups, i.e., skip */
-		if (e - str) {
-			/* termination added */
-			char *name = strndup(str, e - str);
-			if (!name)
-				goto out_err;
+	if (prefix_len < 0)
+		goto out_err;
 
-			cgrp = cgroup__new(name, open_cgroup);
-			free(name);
-			if (cgrp == NULL)
-				goto out_err;
-		} else {
-			cgrp = NULL;
-		}
+	list_for_each_entry(cn, &cgroup_list, list) {
+		char *name;
+
+		if (!cn->used)
+			continue;
+
+		/* cgroup_name might have a full path, skip the prefix */
+		name = cn->name + prefix_len;
+		if (name[0] == '/' && name[1])
+			name++;
+		cgrp = cgroup__new(name, open_cgroup);
 
 		leader = NULL;
 		evlist__for_each_entry(orig_list, pos) {
@@ -277,23 +425,19 @@  int evlist__expand_cgroup(struct evlist *evlist, const char *str,
 			if (metricgroup__copy_metric_events(tmp_list, cgrp,
 							    metric_events,
 							    &orig_metric_events) < 0)
-				break;
+				goto out_err;
 		}
 
 		perf_evlist__splice_list_tail(evlist, &tmp_list->core.entries);
 		tmp_list->core.nr_entries = 0;
-
-		if (!p) {
-			ret = 0;
-			break;
-		}
-		str = p+1;
 	}
+	ret = 0;
 
 out_err:
 	evlist__delete(orig_list);
 	evlist__delete(tmp_list);
 	rblist__exit(&orig_metric_events);
+	release_cgroup_list();
 
 	return ret;
 }