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Date: Mon, 17 Nov 2008 11:21:57 -0800 (PST)
Message-Id: <20081117.112157.146825192.davem@davemloft.net>
To: mingo@elte.hu
Cc: rjw@sisk.pl, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org,
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Subject: Re: [Bug #11308] tbench regression on each kernel release from
 2.6.22 -&gt; 2.6.28
From: David Miller <davem@davemloft.net>
In-Reply-To: <20081117110119.GL28786@elte.hu>
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From: Ingo Molnar <mingo@elte.hu>
Date: Mon, 17 Nov 2008 12:01:19 +0100

> The scheduler's overhead barely even registers on a 16-way x86 system 
> i'm running tbench on. Here's the NMI profile during 64 threads tbench 
> on a 16-way x86 box with an v2.6.28-rc5 kernel [config attached]:

Try a non-NMI profile.

It's the whole of the try_to_wake_up() path that's the problem.