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From: Peter Zijlstra <peterz@infradead.org>
To: Li RongQing <lirongqing@baidu.com>
Cc: 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, linux-kernel@vger.kernel.org
Subject: Re: [Resend][PATCH] sched/fair: micro-optimize pick_next_entity()
Date: Tue, 31 Aug 2021 16:09:39 +0200	[thread overview]
Message-ID: <YS44IzVARx2ZaEUo@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1629872869-19829-1-git-send-email-lirongqing@baidu.com>

On Wed, Aug 25, 2021 at 02:27:49PM +0800, Li RongQing wrote:
> Only check the skip buddy when next buddy and last buddy
> are not picked up, this can save the cycles of checking
> the skip buddy and computation of the second buddy, when
> next and last buddy will be picked up
> for example, yield_to_task_fair() set both next and skip
> buddy

Is that actually measurable?

But looking at it, should we not, instead, move the whole ->skip thing to
the bottom, so we unconditionally check it vs the result of
->next/->last ?

Imagine ->next == ->skip, then we want to avoid running it and not have
->next win.


  reply	other threads:[~2021-08-31 14:11 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-25  6:27 Li RongQing
2021-08-31 14:09 ` Peter Zijlstra [this message]
2021-09-01  7:19   ` 答复: " Li,Rongqing
2021-09-03  3:59   ` Li,Rongqing

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