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Groups > linux.kernel > #1422036
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 2/3] sched: Unloop sched avg decaying |
| Date | 2016-06-14 18:00 +0200 |
| Message-ID | <rJYUV-6QY-3@gated-at.bofh.it> (permalink) |
| References | <rJYrT-6Cf-3@gated-at.bofh.it> <rJYrT-6Cf-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Jun 14, 2016 at 05:28:01PM +0200, Frederic Weisbecker wrote:
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 385c947..0c0578a 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -666,17 +666,17 @@ bool sched_can_stop_tick(struct rq *rq)
> void sched_avg_update(struct rq *rq)
> {
> s64 period = sched_avg_period();
> + s64 delta;
> + u64 rem;
> + int pending;
>
> + delta = (s64)(rq_clock(rq) - rq->age_stamp);
> + if (delta <= period)
> + return;
> +
> + pending = div64_u64_rem(delta, period, &rem);
> + rq->age_stamp += delta - rem;
> + rq->rt_avg >>= pending;
> }
Blergh, and now do the profile on machine that doesn't have major
transistor count dedicated to divisions.
Why not add the division to the nohz exit path only?
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[PATCH 2/3] sched: Unloop sched avg decaying Frederic Weisbecker <fweisbec@gmail.com> - 2016-06-14 17:30 +0200 Re: [PATCH 2/3] sched: Unloop sched avg decaying Peter Zijlstra <peterz@infradead.org> - 2016-06-14 18:00 +0200
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