From: Namhyung Kim <[email protected]> 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 <[email protected]> Acked-by: David Ahern <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Link: http://lkml.kernel.org/r/[email protected] [ Merged fix from Namhyung, see second Link: tag ] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- tools/perf/builtin-sched.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index e108b0f6a246..dc83b803ca54 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -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; -- 2.9.3
