The --for-each-cgroup can have the same cgroup multiple times, but it makes
bpf counters confused (since they have the same cgroup id), and the last
cgroup events are counted only. Let's check the cgroup name before adding
a new entry.
Before:
$ sudo ./perf stat -a --bpf-counters --for-each-cgroup /,/ sleep 1
Performance counter stats for 'system wide':
<not counted> msec cpu-clock /
<not counted> context-switches /
<not counted> cpu-migrations /
<not counted> page-faults /
<not counted> cycles /
<not counted> instructions /
<not counted> branches /
<not counted> branch-misses /
8,016.04 msec cpu-clock / # 7.998 CPUs utilized
6,152 context-switches / # 767.461 /sec
250 cpu-migrations / # 31.187 /sec
442 page-faults / # 55.139 /sec
613,111,487 cycles / # 0.076 GHz
280,599,604 instructions / # 0.46 insn per cycle
57,692,724 branches / # 7.197 M/sec
3,385,168 branch-misses / # 5.87% of all branches
1.002220125 seconds time elapsed
After:
$ sudo ./perf stat -a --bpf-counters --for-each-cgroup /,/ sleep 1
Performance counter stats for 'system wide':
8,013.38 msec cpu-clock / # 7.998 CPUs utilized
6,859 context-switches / # 855.944 /sec
334 cpu-migrations / # 41.680 /sec
345 page-faults / # 43.053 /sec
782,326,119 cycles / # 0.098 GHz
471,645,724 instructions / # 0.60 insn per cycle
94,963,430 branches / # 11.851 M/sec
3,685,511 branch-misses / # 3.88% of all branches
1.001864539 seconds time elapsed
Fixes: bb1c15b60b981 ("perf stat: Support regex pattern in --for-each-cgroup")
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/util/cgroup.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
index e99b41f9be45..cd978c240e0d 100644
--- a/tools/perf/util/cgroup.c
+++ b/tools/perf/util/cgroup.c
@@ -224,6 +224,19 @@ static int add_cgroup_name(const char *fpath, const struct stat *sb __maybe_unus
return 0;
}
+static int check_and_add_cgroup_name(const char *fpath)
+{
+ struct cgroup_name *cn;
+
+ list_for_each_entry(cn, &cgroup_list, list) {
+ if (!strcmp(cn->name, fpath))
+ return 0;
+ }
+
+ /* pretend if it's added by ftw() */
+ return add_cgroup_name(fpath, NULL, FTW_D, NULL);
+}
+
static void release_cgroup_list(void)
{
struct cgroup_name *cn;
@@ -242,7 +255,7 @@ static int list_cgroups(const char *str)
struct cgroup_name *cn;
char *s;
- /* use given name as is - for testing purpose */
+ /* use given name as is when no regex is given */
for (;;) {
p = strchr(str, ',');
e = p ? p : eos;
@@ -253,13 +266,13 @@ static int list_cgroups(const char *str)
s = strndup(str, e - str);
if (!s)
return -1;
- /* pretend if it's added by ftw() */
- ret = add_cgroup_name(s, NULL, FTW_D, NULL);
+
+ ret = check_and_add_cgroup_name(s);
free(s);
- if (ret)
+ if (ret < 0)
return -1;
} else {
- if (add_cgroup_name("", NULL, FTW_D, NULL) < 0)
+ if (check_and_add_cgroup_name("/") < 0)
return -1;
}
--
2.39.0.314.g84b9a713c41-goog
