linux-kernel - Re: CFS review

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Message-ID: <Pine.LNX.4.64.0708101909190.1817@scrub.home>
Date:	Fri, 10 Aug 2007 19:19:22 +0200 (CEST)
From:	Roman Zippel <zippel@...ux-m68k.org>
To:	Mike Galbraith <efault@....de>
cc:	Ingo Molnar <mingo@...e.hu>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andi Kleen <andi@...stfloor.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: CFS review

Hi,

On Fri, 10 Aug 2007, Mike Galbraith wrote:

> I guess I'm going to have to give up on trying to reproduce this... my
> 3GHz P4 is just not getting there from here.  Last attempt, compiled UP,
> HZ=1000 dynticks, full preempt and highres timers fwiw.
> 
> 6392 root      20   0  1696  332  248 R 25.5  0.0   3:00.14 0 lt
> 6393 root      20   0  1696  332  248 R 24.9  0.0   3:00.15 0 lt
> 6391 root      20   0  1696  488  404 R 24.7  0.0   3:00.20 0 lt
> 6394 root      20   0  2888 1232 1028 R 24.5  0.1   2:58.58 0 sh

Except for UP and HZ=1000, everything else is pretty much turned off.
If you use a very recent kernel, the problem may not be visible like this 
anymore.
It may be a bit easier to reproduce, if you change the end time t0 in lt.c 
a little. Also try to start the busy loop first.

bye, Roman
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