perf cgroup: Simplify arguments when tracking multiple events
When using -G with one cgroup and -e with multiple events, only the
first event gets the correct cgroup setting, all events from the second
onwards will track system-wide events.
If the user wants to track multiple events for a specific cgroup, the
user must give parameters like the following:
$ perf stat -e e1 -e e2 -e e3 -G test,test,test
This patch simplify this case, just type one cgroup:
$ perf stat -e e1 -e e2 -e e3 -G test
$ mkdir -p /sys/fs/cgroup/perf_event/empty_cgroup
$ perf stat -e cycles -e cache-misses -a -I 1000 -G empty_cgroup
Before:
1.001007226 <not counted> cycles empty_cgroup
1.001007226 7,506 cache-misses
After:
1.000834097 <not counted> cycles empty_cgroup
1.000834097 <not counted> cache-misses empty_cgroup
Signed-off-by: weiping zhang <zhangweiping@didichuxing.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180129154805.GA6284@localhost.didichuxing.com
[ Improved the doc text a bit, providing an example for cgroup + system wide counting ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
index 984f691..5dd9b5e 100644
--- a/tools/perf/util/cgroup.c
+++ b/tools/perf/util/cgroup.c
@@ -157,9 +157,11 @@
int unset __maybe_unused)
{
struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
+ struct perf_evsel *counter;
+ struct cgroup_sel *cgrp = NULL;
const char *p, *e, *eos = str + strlen(str);
char *s;
- int ret;
+ int ret, i;
if (list_empty(&evlist->entries)) {
fprintf(stderr, "must define events before cgroups\n");
@@ -188,5 +190,18 @@
break;
str = p+1;
}
+ /* for the case one cgroup combine to multiple events */
+ i = 0;
+ if (nr_cgroups == 1) {
+ evlist__for_each_entry(evlist, counter) {
+ if (i == 0)
+ cgrp = counter->cgrp;
+ else {
+ counter->cgrp = cgrp;
+ refcount_inc(&cgrp->refcnt);
+ }
+ i++;
+ }
+ }
return 0;
}