[PATCH 6.9 014/374] perf sched timehist: Fix -g/--call-graph option failure

Greg Kroah-Hartman
2024-06-06T14:08:39Z

From: Yang Jihong <yangjihong@bytedance.com>

[ Upstream commit 6e4b398770d5023eb6383da9360a23bd537c155b ]

When 'perf sched' enables the call-graph recording, sample_type of dummy
event does not have PERF_SAMPLE_CALLCHAIN, timehist_check_attr() checks
that the evsel does not have a callchain, and set show_callchain to 0.

Currently 'perf sched timehist' only saves callchain when processing the
'sched:sched_switch event', timehist_check_attr() only needs to determine
whether the event has PERF_SAMPLE_CALLCHAIN.

Before:

# perf sched record -g true
[ perf record: Woken up 0 times to write data ]
[ perf record: Captured and wrote 4.153 MB perf.data (7536 samples) ]
# perf sched timehist
Samples do not have callchains.
time cpu task name wait time sch delay run time
[tid/pid] (msec) (msec) (msec)
--------------- ------ ------------------------------ --------- --------- ---------
147851.826019 [0000] perf[285035] 0.000 0.000 0.000
147851.826029 [0000] migration/0[15] 0.000 0.003 0.009
147851.826063 [0001] perf[285035] 0.000 0.000 0.000
147851.826069 [0001] migration/1[21] 0.000 0.003 0.006
<SNIP>

After:

# perf sched record -g true
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 2.572 MB perf.data (822 samples) ]
# perf sched timehist
time cpu task name waittime sch delay runtime
[tid/pid] (msec) (msec) (msec)
----------- --- --------------- -------- -------- -----
4193.035164 [0] perf[277062] 0.000 0.000 0.000 __traceiter_sched_switch <- __traceiter_sched_switch <- __sched_text_start <- preempt_schedule_common <- __cond_resched <- __wait_for_common <- wait_for_completion
4193.035174 [0] migration/0[15] 0.000 0.003 0.009 __traceiter_sched_switch <- __traceiter_sched_switch <- __sched_text_start <- smpboot_thread_fn <- kthread <- ret_from_fork
4193.035207 [1] perf[277062] 0.000 0.000 0.000 __traceiter_sched_switch <- __traceiter_sched_switch <- __sched_text_start <- preempt_schedule_common <- __cond_resched <- __wait_for_common <- wait_for_completion
4193.035214 [1] migration/1[21] 0.000 0.003 0.007 __traceiter_sched_switch <- __traceiter_sched_switch <- __sched_text_start <- smpboot_thread_fn <- kthread <- ret_from_fork
<SNIP>

Fixes: 9c95e4ef06572349 ("perf evlist: Add evlist__findnew_tracking_event() helper")
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Yang Jihong <yangjihong@bytedance.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yang Jihong <yangjihong1@huawei.com>
Link: https://lore.kernel.org/r/20240401062724.1006010-2-yangjihong@bytedance.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/builtin-sched.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index b248c433529a8..1bfb223473715 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2963,8 +2963,11 @@ static int timehist_check_attr(struct perf_sched *sched,
return -1;
}

- if (sched->show_callchain && !evsel__has_callchain(evsel)) {
- pr_info("Samples do not have callchains.\n");
+ /* only need to save callchain related to sched_switch event */
+ if (sched->show_callchain &&
+ evsel__name_is(evsel, "sched:sched_switch") &&
+ !evsel__has_callchain(evsel)) {
+ pr_info("Samples of sched_switch event do not have callchains.\n");
sched->show_callchain = 0;
symbol_conf.use_callchain = 0;
}
--
2.43.0