Subject: Re: scheduler vs hardware? (was Re: another i7  (linux) bug?)
From: Mike Galbraith <efault@gmx.de>
To: Luca Zini <luca.zini@gmail.com>
Cc: aagaande@gmail.com, rdelcueto@hotmail.com, mingo@elte.hu,
       a.p.zijlstra@chello.nl, linux-kernel <linux-kernel@vger.kernel.org>,
       Alex Chiang <achiang@hp.com>
In-Reply-To: <20100121215438.GK17684@ldl.fc.hp.com>
References: <201001211258.23499.luca.zini@gmail.com>
	 <20100121215438.GK17684@ldl.fc.hp.com>
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Date: Fri, 22 Jan 2010 08:19:18 +0100
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> if I run a cpu intensive process with the lowest priority (19
> from man nice) I obtain much better performance that with the
> highest priority available (-20 from man nice).
>
> For example the same file is processed by lame in 8.7 seconds
> at the lowest priority, and in 12 seconds at the highest
> priority.  Before posting a bug I wold like to understand if
> this is a problem related to the i7 mobile (my processor is a
> i7 Q720).
> 
> As far as I tested on the same laptop series (dell studio 15),
> with the same kernel this problem does not exists.

So you only see this on the i7.  That's odd.  Can you try 33-rc5?

Posting a reliable reproducer would be nice.  It'd also be nice to see
what all is running when you see this, and where.

	-Mike

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