[PATCH v2] perf sched: Fix sched latency analysis incorrect

From: Chunxin Zang
Date: Thu Mar 16 2023 - 21:54:02 EST


'perf sched latency' is incorrect to get process schedule latency
when it used 'sched:sched_wakeup' to analysis perf.data.

Because 'perf record' prefer use 'sched:sched_waking' to
'sched:sched_wakeup' since commit d566a9c2d482 ("perf sched: Prefer
sched_waking event when it exists"). It's very reasonable to
evaluate process schedule latency.

Similarly, update sched latency/map/replay to use sched_waking events.

I used 'perf record -e “sched:* "' to record both wakeup and waking events,
and use fixed perf version to analysis them, the result is correct.
Because the function "latency_wakeup_event” will change atom->state to
THREAD_WAIT_CPU at waking event, and judge the 'atom->state != THREAD_SLEEPING’
is false then returned at wakeup event.

Signed-off-by: Chunxin Zang <zangchunxin@xxxxxxxxxxx>
Signed-off-by: Jerry Zhou <zhouchunhua@xxxxxxxxxxx>
---
tools/perf/builtin-sched.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 86e18575c9be..1af4ec1ac824 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1819,6 +1819,7 @@ static int perf_sched__read_events(struct perf_sched *sched)
const struct evsel_str_handler handlers[] = {
{ "sched:sched_switch", process_sched_switch_event, },
{ "sched:sched_stat_runtime", process_sched_runtime_event, },
+ { "sched:sched_waking", process_sched_wakeup_event, },
{ "sched:sched_wakeup", process_sched_wakeup_event, },
{ "sched:sched_wakeup_new", process_sched_wakeup_event, },
{ "sched:sched_migrate_task", process_sched_migrate_task_event, },
--
2.25.1

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