Re: [PATCH 1/2] perf sched timehist: Fix --idle-hist when no callchains

Arnaldo Carvalho de Melo
2016-12-13T13:05:04Z

Em Tue, Dec 13, 2016 at 07:49:44PM +0900, Namhyung Kim escreveu:
> Hi Arnaldo,
>
> On Tue, Dec 13, 2016 at 07:32:02AM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Tue, Dec 13, 2016 at 05:06:31PM +0900, Namhyung Kim escreveu:
> > > When idle hist is enabled, the itr->last_thread should be set so that
> > > it can find which thread run before idle task. But it was only set in
> > > the save_idle_callchain(). This makes idle task doesn't show up in
> > > the output when callchain is not recorded.
> >
> > It is important to provide a Fixes: tag so that I can check if the
> > problem was introduced by some patch still not sent to Ingo, in which
> > case I could try and merge them, is this the case here?
>
> Yes,
>
> Fixes: b50c3ab0f1cc ("perf sched timehist: Save callchain when entering idle")

Ok, merged this fix with b50c3ab0f1cc, adding a second Link tag pointing
to this fix, now to the second fix...

- Arnaldo

> Thanks,
> Namhyung
>
>
> >
> > > Before:
> > >
> > > $ perf sched timehist --idle-hist
> > > Samples do not have callchains.
> > > time cpu task name wait time sch delay run time
> > > [tid/pid] (msec) (msec) (msec)
> > > --------------- ------ -------------------- --------- --------- ---------
> > > 197731.753834 [0001] perf[27469] 0.000 0.000 0.000
> > > 197731.753915 [0003] migration/3[23] 0.000 0.000 0.000
> > > 197731.754335 [0002] firefox[17773/17739] 0.000 0.000 0.000
> > > 197731.754486 [0001] sleep[27470] 0.000 0.000 0.000
> > > 197731.754981 [0002] firefox[17773/17739] 0.000 0.000 0.000
> > > 197731.755994 [0002] firefox[17773/17739] 0.000 0.000 0.000
> > > ...
> > >
> > > After:
> > >
> > > 197731.753834 [0001] perf[27469] 0.000 0.000 0.000
> > > 197731.753914 [0001] <idle> 0.000 0.000 0.079
> > > 197731.753915 [0003] migration/3[23] 0.000 0.000 0.000
> > > 197731.754335 [0002] firefox[17773/17739] 0.000 0.000 0.000
> > > 197731.754486 [0001] sleep[27470] 0.000 0.000 0.000
> > > 197731.754903 [0002] <idle> 0.047 0.000 0.567
> > > 197731.754981 [0002] firefox[17773/17739] 0.000 0.000 0.567
> > > 197731.755922 [0002] <idle> 0.078 0.000 0.941
> > > 197731.755994 [0002] firefox[17773/17739] 0.000 0.000 0.941
> > > 197731.756625 [0003] <idle> 0.123 0.000 2.709
> > > ...
> > >
> > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > > ---
> > > tools/perf/builtin-sched.c | 33 +++++++++++++++++----------------
> > > 1 file changed, 17 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> > > index 0750e938a656..405a91d0515f 100644
> > > --- a/tools/perf/builtin-sched.c
> > > +++ b/tools/perf/builtin-sched.c
> > > @@ -2102,26 +2102,12 @@ static struct thread *get_idle_thread(int cpu)
> > > return idle_threads[cpu];
> > > }
> > >
> > > -static void save_idle_callchain(struct thread *thread,
> > > +static void save_idle_callchain(struct idle_thread_runtime *itr,
> > > struct perf_sample *sample)
> > > {
> > > - struct thread *idle;
> > > - struct idle_thread_runtime *itr;
> > > -
> > > if (!symbol_conf.use_callchain || sample->callchain == NULL)
> > > return;
> > >
> > > - idle = get_idle_thread(sample->cpu);
> > > - if (idle == NULL) {
> > > - pr_err("Failed to get idle thread for cpu %d.\n", sample->cpu);
> > > - return;
> > > - }
> > > -
> > > - itr = thread__priv(idle);
> > > - if (itr == NULL)
> > > - return;
> > > -
> > > - itr->last_thread = thread;
> > > callchain_cursor__copy(&itr->cursor, &callchain_cursor);
> > > }
> > >
> > > @@ -2179,9 +2165,24 @@ 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(thread, sample);
> > > + save_idle_callchain(itr, sample);
> > > }
> > > }
> > >
> > > --
> > > 2.10.2