linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: Vincent Guittot <vincent.guittot@linaro.org>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Juri Lelli <juri.lelli@redhat.com>,
	Barry Song <song.bao.hua@hisilicon.com>,
	Peter Ziljstra <peterz@infradead.org>,
	Aubrey Li <aubrey.li@linux.intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Linux-ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 0/4] Reduce scanning of runqueues in select_idle_sibling
Date: Thu, 10 Dec 2020 09:00:49 +0100	[thread overview]
Message-ID: <CAKfTPtCToad1ZwMRi28iC=MQ2D+vnTBLKBU+UOBanTWnuQQzRA@mail.gmail.com> (raw)
In-Reply-To: <20201209143748.GP3371@techsingularity.net>

On Wed, 9 Dec 2020 at 15:37, Mel Gorman <mgorman@techsingularity.net> wrote:
>
> On Tue, Dec 08, 2020 at 03:34:57PM +0000, Mel Gorman wrote:
> > Changelog since v1
> > o Drop single-pass patch                                              (vincent)
> > o Scope variables used for SIS_AVG_CPU                                        (dietmar)
> > o Remove redundant assignment                                         (dietmar
> >
> > This reduces the amount of runqueue scanning in select_idle_sibling in
> > the worst case.
> >
> > Patch 1 removes SIS_AVG_CPU because it's unused.
> >
> > Patch 2 moves all SIS_PROP-related calculations under SIS_PROP
> >
> > Patch 3 improves the hit rate of p->recent_used_cpu to reduce the amount
> >       of scanning. It should be relatively uncontroversial
> >
> > Patch 4 returns an idle candidate if one is found while scanning for a
> >       free core.
> >
>
> Any other objections to the series? Vincent marked 1, 3 and 4 as
> reviewed. While patch 2 had some mild cosmetic concerns, I think the
> version and how it treats SIS_PROP is fine as it is to keep it
> functionally equivalent to !SIS_PROP and without adding too many
> SIS_PROP checks.

while testing your patchset and Aubrey one on top of tip, I'm facing
some perf regression on my arm64 numa system on hackbench and reaim.
The regression seems to comes from your patchset but i don't know
which patch in particular yet

hackbench -l 256000 -g 1

v5.10-rc7 + tip/sched/core 13,255(+/- 3.22%)
with your patchset         15.368(+/- 2.74)  -15.9%

I'm also seeing perf regression on reaim but this one needs more
investigation before confirming

TBH, I was not expecting regressions. I'm running more test to find
which patch is the culprit


>
> --
> Mel Gorman
> SUSE Labs

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-12-10  8:02 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-08 15:34 [PATCH 0/4] Reduce scanning of runqueues in select_idle_sibling Mel Gorman
2020-12-08 15:34 ` [PATCH 1/4] sched/fair: Remove SIS_AVG_CPU Mel Gorman
2020-12-08 16:13   ` Vincent Guittot
2020-12-08 15:34 ` [PATCH 2/4] sched/fair: Move avg_scan_cost calculations under SIS_PROP Mel Gorman
2020-12-08 16:03   ` Vincent Guittot
2020-12-08 16:30     ` Mel Gorman
2020-12-09  5:28     ` Li, Aubrey
2020-12-09  9:05       ` Mel Gorman
2020-12-09 11:07         ` Li, Aubrey
2020-12-09 11:33           ` Mel Gorman
2020-12-10  5:18   ` Li, Aubrey
2020-12-10  9:32     ` Mel Gorman
2020-12-08 15:35 ` [PATCH 3/4] sched/fair: Do not replace recent_used_cpu with the new target Mel Gorman
2020-12-08 16:14   ` Vincent Guittot
2020-12-10  9:40     ` Vincent Guittot
2020-12-11  6:25   ` Hillf Danton
2020-12-11  9:02     ` Mel Gorman
2020-12-11  9:34       ` Hillf Danton
2020-12-11  9:45         ` Mel Gorman
2020-12-08 15:35 ` [PATCH 4/4] sched/fair: Return an idle cpu if one is found after a failed search for an idle core Mel Gorman
2020-12-08 16:15   ` Vincent Guittot
2020-12-09 14:37 ` [PATCH 0/4] Reduce scanning of runqueues in select_idle_sibling Mel Gorman
2020-12-10  8:00   ` Vincent Guittot [this message]
2020-12-10  9:38     ` Vincent Guittot
2020-12-10 11:04       ` Mel Gorman
2020-12-11  9:51         ` Vincent Guittot
2020-12-11 10:23           ` Mel Gorman
2020-12-12 10:02             ` 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='CAKfTPtCToad1ZwMRi28iC=MQ2D+vnTBLKBU+UOBanTWnuQQzRA@mail.gmail.com' \
    --to=vincent.guittot@linaro.org \
    --cc=aubrey.li@linux.intel.com \
    --cc=juri.lelli@redhat.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mgorman@techsingularity.net \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=song.bao.hua@hisilicon.com \
    --cc=valentin.schneider@arm.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;
as well as URLs for NNTP newsgroup(s).