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Message-ID: <4AA6AFCE.5080406@garzik.org>
Date:	Tue, 08 Sep 2009 15:26:06 -0400
From:	Jeff Garzik <jeff@...zik.org>
To:	Serge Belyshev <belyshev@...ni.sinp.msu.ru>
CC:	Jesse Brandeburg <jesse.brandeburg@...il.com>,
	Ingo Molnar <mingo@...e.hu>, Con Kolivas <kernel@...ivas.org>,
	linux-kernel@...r.kernel.org,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Mike Galbraith <efault@....de>
Subject: Re: Epic regression in throughput since v2.6.23
On 09/08/2009 03:20 PM, Serge Belyshev wrote:
> Jeff Garzik<jeff@...zik.org>  writes:
>
>> You will almost certainly see idle CPUs/threads with "make -jN_CPUS"
>> due to processes waiting for I/O.
>
> Just to clarify: I have excluded all I/O effects in my plots completely
> by building completely from tmpfs. Also, before each actual measurment
> there was a thrown-off "pre-caching" one.  And my box has 8GB of RAM.
You could always one-up that by using ramfs ;)
	Jeff
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