Re: [PATCH v3 2/2] perf stat: Support regex pattern in --for-each-cgroup

Jiri Olsa
2020-10-27T13:44:35Z

On Tue, Oct 27, 2020 at 04:28:55PM +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%)
>
> 1.000892614 seconds time elapsed
>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Acked-by: Jiri Olsa <jolsa@redhat.com>

thanks,
jirka

> ---
> tools/perf/Documentation/perf-stat.txt | 5 +-
> tools/perf/builtin-stat.c | 5 +-
> tools/perf/util/cgroup.c | 198 ++++++++++++++++++++++---
> 3 files changed, 182 insertions(+), 26 deletions(-)
>
> 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/builtin-stat.c b/tools/perf/builtin-stat.c
> index b01af171d94f..6709578128c9 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -2235,8 +2235,11 @@ int cmd_stat(int argc, const char **argv)
> }
>
> if (evlist__expand_cgroup(evsel_list, stat_config.cgroup_list,
> - &stat_config.metric_events, true) < 0)
> + &stat_config.metric_events, true) < 0) {
> + parse_options_usage(stat_usage, stat_options,
> + "for-each-cgroup", 0);
> goto out;
> + }
> }
>
> target__validate(&target);
> diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
> index b81324a13a2b..704333748549 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 +381,27 @@ 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);
> + if (cgrp == NULL)
> + goto out_err;
>
> leader = NULL;
> evlist__for_each_entry(orig_list, pos) {
> @@ -277,23 +427,25 @@ 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;
> + if (list_empty(&evlist->core.entries)) {
> + fprintf(stderr, "no cgroup matched: %s\n", str);
> + goto out_err;
> }
>
> + ret = 0;
> +
> out_err:
> evlist__delete(orig_list);
> evlist__delete(tmp_list);
> rblist__exit(&orig_metric_events);
> + release_cgroup_list();
>
> return ret;
> }
> --
> 2.29.0.rc2.309.g374f81d7ae-goog
>