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@xxxxxxx> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/