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Subject[PATCH 1/2] perf stat: Fix event grouping on forked task
Date
When event group is enabled for forked task (i.e. no target task was
specified) all events were disabled and marked ->enable_on_exec.
However they are not counted at all since only group leader will be
enabled on exec actually. So the result looked like below:

$ ./perf stat --group -- sleep 1

Performance counter stats for 'sleep 1':

0.554926 task-clock # 0.001 CPUs utilized
<not counted> context-switches
<not counted> CPU-migrations
<not counted> page-faults
<not counted> cycles
<not supported> stalled-cycles-frontend
<not supported> stalled-cycles-backend
<not counted> instructions
<not counted> branches
<not counted> branch-misses

1.001228093 seconds time elapsed

Fix it by disabling group leader only.

Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
---
tools/perf/builtin-stat.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index e54cbc9fc4fd..cda1e757ea87 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -296,7 +296,7 @@ static int create_perf_stat_counter(struct perf_evsel *evsel,
if (system_wide)
return perf_evsel__open_per_cpu(evsel, evsel_list->cpus,
group, group_fd);
- if (!target_pid && !target_tid) {
+ if (!target_pid && !target_tid && (!group || evsel == first)) {
attr->disabled = 1;
attr->enable_on_exec = 1;
}
--
1.7.9


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