From: Mel Gorman <mgorman@techsingularity.net>
To: Hillf Danton <hdanton@sina.com>
Cc: Juri Lelli <juri.lelli@redhat.com>,
Barry Song <song.bao.hua@hisilicon.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
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 3/4] sched/fair: Do not replace recent_used_cpu with the new target
Date: Fri, 11 Dec 2020 09:02:28 +0000 [thread overview]
Message-ID: <20201211090228.GU3371@techsingularity.net> (raw)
In-Reply-To: <20201211062542.3082-1-hdanton@sina.com>
On Fri, Dec 11, 2020 at 02:25:42PM +0800, Hillf Danton wrote:
> On Tue, 8 Dec 2020 15:35:00 +0000 Mel Gorman wrote:
> > @@ -6277,17 +6277,13 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
> >
> > /* Check a recently used CPU as a potential idle candidate: */
> > recent_used_cpu = p->recent_used_cpu;
> > + p->recent_used_cpu = prev;
> > if (recent_used_cpu != prev &&
> > recent_used_cpu != target &&
> > cpus_share_cache(recent_used_cpu, target) &&
> > (available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) &&
> > cpumask_test_cpu(p->recent_used_cpu, p->cpus_ptr) &&
>
> Typo? Fix it in spin if so.
>
What typo?
> > asym_fits_capacity(task_util, recent_used_cpu)) {
> > - /*
> > - * Replace recent_used_cpu with prev as it is a potential
> > - * candidate for the next wake:
> > - */
> > - p->recent_used_cpu = prev;
> > return recent_used_cpu;
>
> I prefer to update the recent CPU after llc check.
>
That would prevent recent_used_cpu leaving the LLC the task first
started on.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2020-12-11 9:03 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 [this message]
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
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
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