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Date: Fri, 10 Aug 2007 19:19:22 +0200 (CEST)
From: Roman Zippel <zippel@linux-m68k.org>
X-X-Sender: roman@scrub.home
To: Mike Galbraith <efault@gmx.de>
cc: Ingo Molnar <mingo@elte.hu>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Andi Kleen <andi@firstfloor.org>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
Subject: Re: CFS review
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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