From: Valentin Schneider <valentin.schneider@arm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched/fair: improve spreading of utilization
Date: Fri, 13 Mar 2020 17:34:09 +0000 [thread overview]
Message-ID: <jhjzhcknoq6.mognet@arm.com> (raw)
In-Reply-To: <CAKfTPtCopLDoUsC+Mt6k99Hdn52pcKkrNYQsYNRW5LdgyMg4Nw@mail.gmail.com>
On Fri, Mar 13 2020, Vincent Guittot wrote:
>> My point is that if we prevent this for migrate_util, it would make
>> sense to prevent it for migrate_task, but it's not straightforward since
>
> hmm but we don't want to prevent this active balance for migrate_task
> because of cases like the one you mentioned above.
>
> we might consider to finally select a CPU with only 1 running task
> with migrate_util if there is no other CPU with more than 1 task. But
> this would complexify the code and I don't think it's possible because
> migrate_util is used to pull some utilizations from an overloaded
> group which must have a CPU with a waiting task to be overloaded.
>
OK, so what we may want in the future is a tighter link between
find_busiest_queue() and voluntary_active_balance(). I don't see a neat
way of doing this right now, I'll ponder over it.
Thanks for keeping up with my rambling.
next prev parent reply other threads:[~2020-03-13 17:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-12 16:54 [PATCH] sched/fair: improve spreading of utilization Vincent Guittot
2020-03-13 10:26 ` Peter Zijlstra
2020-03-13 11:00 ` Valentin Schneider
2020-03-13 11:24 ` Vincent Guittot
2020-03-13 11:28 ` Valentin Schneider
2020-03-13 12:42 ` Valentin Schneider
2020-03-13 12:55 ` Vincent Guittot
2020-03-13 14:26 ` Vincent Guittot
2020-03-13 15:47 ` Valentin Schneider
2020-03-13 16:09 ` Vincent Guittot
2020-03-13 16:57 ` Valentin Schneider
2020-03-13 17:12 ` Vincent Guittot
2020-03-13 17:34 ` Valentin Schneider [this message]
2020-03-20 12:58 ` [tip: sched/core] sched/fair: Improve " tip-bot2 for Vincent Guittot
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=jhjzhcknoq6.mognet@arm.com \
--to=valentin.schneider@arm.com \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=vincent.guittot@linaro.org \
/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;
as well as URLs for NNTP newsgroup(s).