Re: [PATCH v3 2/2] sched: consider missed ticks when updating global cpu load

From: Peter Zijlstra
Date: Tue Oct 13 2015 - 03:04:44 EST


On Mon, Oct 12, 2015 at 07:45:35PM +0200, Frederic Weisbecker wrote:
> > I think it will take more than a single patch to rework all of
> > update_process_times(). And we should also ask Thomas for his opinion,
> > but I think we want:
> >
> > - make update_process_times() take a nr_ticks argument
> > - fixup everything below it
> >
> > - fix tick_nohz_handler to not ignore the hrtimer_forward()
> > return value and pass it into
> > tick_sched_handle()/update_process_times().
> >
> > (assuming this is the right oneshot tick part, tick-common
> > seems to be about periodic timers which aren't used much ?!)
>
> this_nohz_handler() is the low res nohz handler. tick_sched_handle()
> is the high res one (I should rename these). I think we should rather
> find out the pending updates from update_process_times() itself and pass
> it to scheduler_tick() which is the one interested in it.

tick_nohz_handler() calls tick_sched_handler() ?!

And tick_nohz_handler() actually computes the number of ticks -- which
we then happily ignore.

Why compute it again a few functions down?
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