From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: mingo@redhat.com, juri.lelli@redhat.com,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched/pelt: sync util/runnable_sum with PELT window when propagating
Date: Thu, 23 Apr 2020 21:29:30 +0200 [thread overview]
Message-ID: <20200423192930.GY2483@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20200422151401.9147-1-vincent.guittot@linaro.org>
On Wed, Apr 22, 2020 at 05:14:01PM +0200, Vincent Guittot wrote:
> update_tg_cfs_util/runnable() propagate the impact of the attach/detach of
> an entity down into the cfs_rq hierarchy which must keep the sync with
> the current pelt window.
>
> Even if we can't sync child rq and its group se, we can sync the group se
> and parent cfs_rq with current PELT window. In fact, we must keep them sync
> in order to stay also synced with others se and group se that are already
> attached to the cfs_rq.
>
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> kernel/sched/fair.c | 26 ++++++--------------------
> 1 file changed, 6 insertions(+), 20 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 02f323b85b6d..ca6aa89c88f2 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3441,52 +3441,38 @@ static inline void
> update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
> {
> long delta = gcfs_rq->avg.util_avg - se->avg.util_avg;
> + u32 divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib;
>
> /* Nothing to update */
> if (!delta)
> return;
>
> - /*
> - * The relation between sum and avg is:
> - *
> - * LOAD_AVG_MAX - 1024 + sa->period_contrib
> - *
> - * however, the PELT windows are not aligned between grq and gse.
> - */
Instead of deleting this, could we perhaps extend it?
next prev parent reply other threads:[~2020-04-23 19:30 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-22 15:14 [PATCH] sched/pelt: sync util/runnable_sum with PELT window when propagating Vincent Guittot
2020-04-23 14:30 ` Dietmar Eggemann
2020-04-23 16:17 ` Vincent Guittot
2020-04-24 12:07 ` Dietmar Eggemann
2020-04-24 12:47 ` Vincent Guittot
2020-04-23 19:29 ` Peter Zijlstra [this message]
2020-04-24 7:37 ` Vincent Guittot
2020-04-24 8:41 ` Dietmar Eggemann
2020-04-24 8:54 ` Vincent Guittot
2020-04-24 9:06 ` Dietmar Eggemann
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