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From: Peter Zijlstra <peterz@infradead.org>
To: Mike Galbraith <efault@gmx.de>, kprateek.nayak@amd.com
Cc: Chunxin Zang <spring.cxz@gmail.com>,
	mingo@redhat.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, vschneid@redhat.com,
	linux-kernel@vger.kernel.org, yu.c.chen@intel.com,
	yangchen11@lixiang.com, zhouchunhua@lixiang.com,
	zangchunxin@lixiang.com
Subject: Re: [PATCH] sched/fair: Reschedule the cfs_rq when current is ineligible
Date: Mon, 27 May 2024 10:05:03 +0200	[thread overview]
Message-ID: <20240527080503.GU22557@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <e17d3d90440997b970067fe9eaf088903c65f41d.camel@gmx.de>

On Sat, May 25, 2024 at 08:41:28AM +0200, Mike Galbraith wrote:

> -	if (pick_eevdf(cfs_rq) == pse)
> -		goto preempt;
> -
> -	return;
> +	if (pick_eevdf(cfs_rq) == se)
> +		return;

Right, this will preempt more.

This is probably going to make Prateek's case worse though. Then again,
I was already leaning to towards not making his stronger slice
protection default, because it simply hurts too much elsewhere.

Still, his observation that placing tasks can move V left which in turn
can cause the just scheduled in current non-eligible and cause
over-scheduling is valid -- just not sure what to do about it yet.

  parent reply	other threads:[~2024-05-27  8:05 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-24 13:40 [PATCH] sched/fair: Reschedule the cfs_rq when current is ineligible Chunxin Zang
2024-05-24 15:30 ` Chen Yu
2024-05-28  2:42   ` Chunxin Zang
2024-05-28  5:02     ` K Prateek Nayak
2024-05-28  7:18       ` Chunxin Zang
2024-05-28  7:47         ` K Prateek Nayak
2024-06-05 17:19       ` Chen Yu
2024-06-06  1:46         ` Chunxin Zang
2024-06-07  2:38           ` Chen Yu
2024-06-11 13:10             ` Chunxin Zang
2024-06-13 11:45               ` Chen Yu
2024-05-28  6:41     ` Chunxin Zang
2024-05-25  6:41 ` Mike Galbraith
2024-05-25 11:57   ` Chen Yu
2024-05-25 17:22     ` Mike Galbraith
2024-05-27  8:05   ` Peter Zijlstra [this message]
2024-05-27  9:53     ` Mike Galbraith
2024-05-25 11:48 ` Honglei Wang
     [not found]   ` <6AF97701-B8F4-46C6-851E-A8BACE97E8C0@gmail.com>
2024-06-03  2:55     ` Honglei Wang
2024-06-06 12:39       ` Chunxin Zang
2024-06-11 11:39         ` Honglei Wang
2024-05-29  6:06 ` kernel test robot

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