perf sched timehist: Save callchain when entering idle (699b5b92) · Commits · 戴 / test

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>

tools/perf/builtin-sched.c

+30 −0

Original line number	Diff line number	Diff line
		@@ -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;

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