From: Kuyo Chang <kuyo.chang@mediatek.com>
To: Dietmar Eggemann <dietmar.eggemann@arm.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 17:29:28 +0800 [thread overview]
Message-ID: <f2579de9b0555568eff94ff83f8695af7b218349.camel@mediatek.com> (raw)
In-Reply-To: <f7913fea-d110-9140-6dfa-72561c3fbefd@arm.com>
On Thu, 2022-04-14 at 11:02 +0200, Dietmar Eggemann wrote:
> 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.
Thanks for your friendly reminder.
>
> > + } 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>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
prev parent reply other threads:[~2022-04-14 9:32 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
2022-04-14 9:29 ` Kuyo Chang [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f2579de9b0555568eff94ff83f8695af7b218349.camel@mediatek.com \
--to=kuyo.chang@mediatek.com \
--cc=bristot@redhat.com \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=juri.lelli@redhat.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=matthias.bgg@gmail.com \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=vincent.guittot@linaro.org \
--cc=wsd_upstream@mediatek.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox