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Message-Id: <20240328055857.383180-1-yangjihong@bytedance.com>
Date: Thu, 28 Mar 2024 13:58:56 +0800
From: Yang Jihong <yangjihong@...edance.com>
To: peterz@...radead.org,
mingo@...hat.com,
acme@...nel.org,
namhyung@...nel.org,
mark.rutland@....com,
alexander.shishkin@...ux.intel.com,
jolsa@...nel.org,
irogers@...gle.com,
adrian.hunter@...el.com,
kan.liang@...ux.intel.com,
james.clark@....com,
linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: yangjihong@...edance.com
Subject: [PATCH 1/2] perf sched timehist: Fix -g/--call-graph option failure
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
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 wait time sch delay run time
[tid/pid] (msec) (msec) (msec)
--------------- ------ ------------------------------ --------- --------- ---------
144193.035164 [0000] 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
144193.035174 [0000] 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
144193.035207 [0001] 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
144193.035214 [0001] 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>
Signed-off-by: Yang Jihong <yangjihong@...edance.com>
---
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 b248c433529a..1bfb22347371 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;
}
--
2.25.1
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