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From: Chen Yu <yu.c.chen@intel.com>
To: Honglei Wang <wanghonglei@didichuxing.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	"Tim Chen" <tim.c.chen@intel.com>,
	Mel Gorman <mgorman@techsingularity.net>,
	"Juri Lelli" <juri.lelli@redhat.com>,
	Rik van Riel <riel@surriel.com>, Aaron Lu <aaron.lu@intel.com>,
	Abel Wu <wuyun.abel@bytedance.com>,
	Yicong Yang <yangyicong@hisilicon.com>,
	"Gautham R . Shenoy" <gautham.shenoy@amd.com>,
	Ingo Molnar <mingo@redhat.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Valentin Schneider <vschneid@redhat.com>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] sched/fair: Choose the CPU where short task is running during wake up
Date: Sat, 1 Oct 2022 00:03:48 +0800	[thread overview]
Message-ID: <YzcTZBTF2H0udyk1@chenyu5-mobl1> (raw)
In-Reply-To: <a6e38a33-0003-d3ea-de9b-cf805aef647f@didichuxing.com>

On 2022-09-29 at 14:59:46 +0800, Honglei Wang wrote:
> > > > @@ -6050,7 +6063,8 @@ wake_affine_idle(int this_cpu, int prev_cpu, int sync)
> > > >   	if (available_idle_cpu(this_cpu) && cpus_share_cache(this_cpu, prev_cpu))
> > > >   		return available_idle_cpu(prev_cpu) ? prev_cpu : this_cpu;
> > > > -	if (sync && cpu_rq(this_cpu)->nr_running == 1)
> > > > +	if ((sync && cpu_rq(this_cpu)->nr_running == 1) ||
> > > > +	    is_short_task(cpu_curr(this_cpu)))
> 
> Seems it a bit breaks idle (or will be idle) purpose of wake_affine_idle()
> here.
Exactly, we should prefer previous idle CPU to 'potential idle' this_cpu to keep
it consistent.
> Maybe we can do it something like this?
> 
> if ((sync || is_short_task(cpu_curr(this_cpu))) &&
> cpu_rq(this_cpu)->nr_running == 1)
>
Yes, Prateek's experimental results has proven your suggestion.

thanks,
Chenyu
> Thanks,
> Honglei

  parent reply	other threads:[~2022-09-30 16:06 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-15 16:54 [RFC PATCH] sched/fair: Choose the CPU where short task is running during wake up Chen Yu
2022-09-15 17:10 ` Tim Chen
2022-09-16 10:49   ` Chen Yu
2022-09-16 11:45 ` Peter Zijlstra
2022-09-17 13:55   ` Chen Yu
2022-09-16 11:47 ` Peter Zijlstra
2022-09-17 14:15   ` Chen Yu
2022-09-26  5:50 ` K Prateek Nayak
2022-09-26 14:39   ` Gautham R. Shenoy
2022-09-29 16:58     ` K Prateek Nayak
2022-09-30 17:26       ` Chen Yu
2022-09-29  5:25   ` Chen Yu
2022-09-29  6:59     ` Honglei Wang
2022-09-29 17:34       ` K Prateek Nayak
2022-09-30  0:58         ` Honglei Wang
2022-09-30 16:03       ` Chen Yu [this message]
2022-09-29 17:19     ` K Prateek Nayak
2022-09-29  8:00 ` Vincent Guittot
2022-09-30 16:53   ` Chen Yu
2022-10-03 12:42     ` Vincent Guittot

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