linux-kernel - Re: [PATCH] sched: recover sched_yield task running time increase

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Date:	Wed, 06 Apr 2011 01:07:30 -0400
From:	Rik van Riel <riel@...hat.com>
To:	Alex Shi <alex.shi@...el.com>
CC:	linux-kernel@...r.kernel.org, a.p.zijlstra@...llo.nl,
	mingo@...e.hu, tim.c.chen@...el.com, shaohua.li@...el.com
Subject: Re: [PATCH] sched: recover sched_yield task running time increase

On 04/05/2011 06:33 PM, Alex Shi wrote:
> commit ac53db596cc08ecb8040c removed the sched_yield task running
> time increase, so the yielded task get more opportunity to be launch
> again. That may not the caller want to be. And this also causes
> volano benchmark drop 50~80 percent performance on core2/NHM/WSM
> machines. This patch recover the sched_yield task vruntime up.
>
> Signed-off-by: alex.shi@...el.com

NACK

This was switched off by default and under
the sysctl sched_compat_yield for a reason.

Reintroducing it under that sysctl option
may be acceptable, but by default it would
be doing the wrong thing for other workloads.
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