Re: [PATCH 2/2] sched: Trace point sched_stat_sleep should cover iowait case

From: Peter Zijlstra
Date: Mon Aug 03 2015 - 14:43:50 EST


On Mon, Aug 03, 2015 at 01:35:28PM -0400, Steven Rostedt wrote:
> On Mon, 27 Jul 2015 09:11:52 -0400
> yangoliver <yang_oliver@xxxxxxxxxxx> wrote:
>
> > Per sched_stat_sleep definition in sched.h, it should include
> > iowait case. This can also relect the design of sum_sleep_runtime
> > statistic, as this counter also includes the io_wait.
> >
> > Signed-off-by: Yong Yang <yangoliver@xxxxxxxxx>
> > ---
> > kernel/sched/fair.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index d113c3b..85677bf 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -3018,6 +3018,8 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
> > se->statistics.sum_sleep_runtime += delta;
> >
> > if (tsk) {
> > + trace_sched_stat_sleep(tsk, delta);
> > +
> > if (tsk->in_iowait) {
> > se->statistics.iowait_sum += delta;
> > se->statistics.iowait_count++;
>

No, that's broken in two ways. Firstly you don't change semantics of
stuff just because of a comment and secondly iowait has nothing what all
to do with INTERRUPTIBLE/sleep vs UNINTERRUPTIBLE/blocked.

And wtf are you doing sending sched patches and not Cc maintainers.
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