From: Valentin Schneider <valentin.schneider@arm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>,
mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
linux-kernel@vger.kernel.org
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: [PATCH 1/3] sched/fair: skip idle cfs_rq
Date: Wed, 06 Jan 2021 15:13:31 +0000 [thread overview]
Message-ID: <jhj1rey3xpg.mognet@arm.com> (raw)
In-Reply-To: <20210106133419.2971-2-vincent.guittot@linaro.org>
On 06/01/21 14:34, Vincent Guittot wrote:
> Don't waste time checking whether an idle cfs_rq could be the busiest
> queue. Furthermore, this can end up selecting a cfs_rq with a high load
> but being idle in case of migrate_load.
>
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Makes sense to me.
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
> ---
> kernel/sched/fair.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 04a3ce20da67..5428b8723e61 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -9389,8 +9389,11 @@ static struct rq *find_busiest_queue(struct lb_env *env,
> if (rt > env->fbq_type)
> continue;
>
> - capacity = capacity_of(i);
> nr_running = rq->cfs.h_nr_running;
> + if (!nr_running)
> + continue;
> +
> + capacity = capacity_of(i);
>
> /*
> * For ASYM_CPUCAPACITY domains, don't pick a CPU that could
> --
> 2.17.1
next prev parent reply other threads:[~2021-01-06 15:14 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-06 13:34 [PATCH 0/3] Reduce number of active LB Vincent Guittot
2021-01-06 13:34 ` [PATCH 1/3] sched/fair: skip idle cfs_rq Vincent Guittot
2021-01-06 15:13 ` Valentin Schneider [this message]
2021-01-06 13:34 ` [PATCH 2/3] sched/fair: don't set LBF_ALL_PINNED unnecessarily Vincent Guittot
2021-01-06 15:07 ` Peter Zijlstra
2021-01-06 15:20 ` Vincent Guittot
2021-01-06 15:32 ` Peter Zijlstra
2021-01-06 15:45 ` Vincent Guittot
2021-01-06 15:13 ` Valentin Schneider
2021-01-06 16:04 ` Vincent Guittot
2021-01-06 13:34 ` [PATCH 3/3] sched/fair: reduce cases for active balance Vincent Guittot
2021-01-06 15:13 ` Peter Zijlstra
2021-01-06 15:41 ` Vincent Guittot
2021-01-06 16:11 ` Peter Zijlstra
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=jhj1rey3xpg.mognet@arm.com \
--to=valentin.schneider@arm.com \
--cc=bristot@redhat.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