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perf sched timehist: Save callchain when entering idle

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In order to investigate the idleness reason, it is necessary to keep the
callchains when entering idle.  This can be identified by the
sched:sched_switch event having the next_pid field as 0.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-4-namhyung@kernel.org
Link: http://lkml.kernel.org/r/20161213080632.19099-1-namhyung@kernel.org
[ Merged fix from Namhyung, see second Link: tag ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2016-12-08 23:47:52 +09:00 committed by Arnaldo Carvalho de Melo
parent 3bc2fa9cb8
commit 699b5b920d
1 changed files with 30 additions and 0 deletions
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30
tools/perf/builtin-sched.c
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@ -200,6 +200,7 @@ struct perf_sched {
/* options for timehist command */
bool summary;
bool summary_only;
bool idle_hist;
bool show_callchain;
unsigned int max_stack;
bool show_cpu_visual;
@ -2101,6 +2102,15 @@ static struct thread *get_idle_thread(int cpu)
return idle_threads[cpu];
}
static void save_idle_callchain(struct idle_thread_runtime *itr,
struct perf_sample *sample)
{
if (!symbol_conf.use_callchain || sample->callchain == NULL)
return;
callchain_cursor__copy(&itr->cursor, &callchain_cursor);
}
/*
* handle runtime stats saved per thread
*/
@ -2154,6 +2164,26 @@ static struct thread *timehist_get_thread(struct perf_sched *sched,
}
save_task_callchain(sched, sample, evsel, machine);
if (sched->idle_hist) {
struct thread *idle;
struct idle_thread_runtime *itr;
idle = get_idle_thread(sample->cpu);
if (idle == NULL) {
pr_err("Failed to get idle thread for cpu %d.\n", sample->cpu);
return NULL;
}
itr = thread__priv(idle);
if (itr == NULL)
return NULL;
itr->last_thread = thread;
/* copy task callchain when entering to idle */
if (perf_evsel__intval(evsel, sample, "next_pid") == 0)
save_idle_callchain(itr, sample);
}
}
return thread;