From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Kuyo Chang <kuyo.chang@mediatek.com>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Matthias Brugger <matthias.bgg@gmail.com>
Cc: wsd_upstream@mediatek.com, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org
Subject: Re: [PATCH 1/1] [PATCH v2]sched/pelt: Refine the enqueue_load_avg calculate method
Date: Thu, 14 Apr 2022 11:02:36 +0200 [thread overview]
Message-ID: <f7913fea-d110-9140-6dfa-72561c3fbefd@arm.com> (raw)
In-Reply-To: <20220414015940.9537-1-kuyo.chang@mediatek.com>
On 14/04/2022 03:59, Kuyo Chang wrote:
> From: kuyo chang <kuyo.chang@mediatek.com>
[...]
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index d4bd299d67ab..159274482c4e 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3829,10 +3829,12 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
>
> se->avg.runnable_sum = se->avg.runnable_avg * divider;
>
> - se->avg.load_sum = divider;
> - if (se_weight(se)) {
> + se->avg.load_sum = se->avg.load_avg * divider;
> + if (se_weight(se) < se->avg.load_sum) {
> se->avg.load_sum =
> - div_u64(se->avg.load_avg * se->avg.load_sum, se_weight(se));
> + div_u64(se->avg.load_sum, se_weight(se));
Seems that this will fit on one line now. No braces needed then.
> + } else {
> + se->avg.load_sum = 1;
> }
>
> enqueue_load_avg(cfs_rq, se);
Looks like taskgroups are not affected since they get always online
with cpu.shares/weight = 1024 (cgroup v1):
cpu_cgroup_css_online() -> online_fair_sched_group() ->
attach_entity_cfs_rq() -> attach_entity_load_avg()
And reweight_entity() does not have this issue.
Tested with `qemu-system-x86_64 ... cores=64 ... -enable-kvm` and
weight=88761 for nice=0 tasks plus forcing se->avg.load_avg = 1 before
the div_u64() in attach_entity_load_avg().
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
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next prev parent reply other threads:[~2022-04-14 9:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 1:59 [PATCH 1/1] [PATCH v2]sched/pelt: Refine the enqueue_load_avg calculate method Kuyo Chang
2022-04-14 7:37 ` Vincent Guittot
2022-04-14 8:25 ` Kuyo Chang
2022-04-14 9:02 ` Dietmar Eggemann [this message]
2022-04-14 9:29 ` Kuyo Chang
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