Commit 96039c7c authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
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perf sched timehist: Split is_idle_sample() 



The is_idle_sample() function actually does more than determining
whether sample come from idle task.  Split the callchain part into
save_task_callchain() to make it clearer.

Also checking prev_pid from trace data looks preferred than just
checking sample->pid since it's possible, although rare, to have invalid
0 pid/tid on scheduling an exiting task.

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Acked-by: default avatarDavid 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/20161208144755.16673-2-namhyung@kernel.org


[ Remove some needless () in some return statements ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent aeafd623

tools/perf/builtin-sched.c

+20 −19
Original line number Diff line number Diff line
@@ -1939,39 +1939,40 @@ static void timehist_update_runtime_stats(struct thread_runtime *r, 
	r->total_run_time += r->dt_run;

}



static bool is_idle_sample(struct perf_sched *sched,

static bool is_idle_sample(struct perf_sample *sample,

			   struct perf_evsel *evsel)

{

	/* pid 0 == swapper == idle task */

	if (strcmp(perf_evsel__name(evsel), "sched:sched_switch") == 0)

		return perf_evsel__intval(evsel, sample, "prev_pid") == 0;



	return sample->pid == 0;

}



static void save_task_callchain(struct perf_sched *sched,

				struct perf_sample *sample,

				struct perf_evsel *evsel,

				struct machine *machine)

{

	struct thread *thread;

	struct callchain_cursor *cursor = &callchain_cursor;



	/* pid 0 == swapper == idle task */

	if (sample->pid == 0)

		return true;



	if (strcmp(perf_evsel__name(evsel), "sched:sched_switch") == 0) {

		if (perf_evsel__intval(evsel, sample, "prev_pid") == 0)

			return true;

	}

	struct thread *thread;



	/* want main thread for process - has maps */

	thread = machine__findnew_thread(machine, sample->pid, sample->pid);

	if (thread == NULL) {

		pr_debug("Failed to get thread for pid %d.\n", sample->pid);

		return false;

		return;

	}



	if (!symbol_conf.use_callchain || sample->callchain == NULL)

		return false;

		return;



	if (thread__resolve_callchain(thread, cursor, evsel, sample,

				      NULL, NULL, sched->max_stack + 2) != 0) {

		if (verbose)

			error("Failed to resolve callchain. Skipping\n");



		return false;

		return;

	}



	callchain_cursor_commit(cursor);
@@ -1994,8 +1995,6 @@ static bool is_idle_sample(struct perf_sched *sched, 


		callchain_cursor_advance(cursor);

	}



	return false;

}



/*
@@ -2111,7 +2110,7 @@ static struct thread *timehist_get_thread(struct perf_sched *sched, 
{

	struct thread *thread;



	if (is_idle_sample(sched, sample, evsel, machine)) {

	if (is_idle_sample(sample, evsel)) {

		thread = get_idle_thread(sample->cpu);

		if (thread == NULL)

			pr_err("Failed to get idle thread for cpu %d.\n", sample->cpu);
@@ -2124,6 +2123,8 @@ static struct thread *timehist_get_thread(struct perf_sched *sched, 
			pr_debug("Failed to get thread for tid %d. skipping sample.\n",

				 sample->tid);

		}



		save_task_callchain(sched, sample, evsel, machine);

	}



	return thread;

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