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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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