Message-ID: <4734F397.7080802@gmx.net>
Date: Sat, 10 Nov 2007 00:56:07 +0100
From: Cyrus Massoumi <cyrusm@gmx.net>
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To: Micah Dowty <micah@vmware.com>
CC: linux-kernel@vger.kernel.org
Subject: Re: High priority tasks break SMP balancer?
References: <20071109223417.GB16250@vmware.com>
In-Reply-To: <20071109223417.GB16250@vmware.com>
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Hi Micah

> On my machine (2-way Opteron with a vanilla 2.6.23.1 kernel) this test
> program will reliably put the scheduler into a state where one CPU has
> both of the busy-looping processes in its runqueue, and the other CPU
> is usually idle. The usually-idle CPU will have a very high cpu_load,
> as reported by /proc/sched_debug.

I tried your program on my machine (C2D, 2.6.17, O(1) scheduler).

Both CPUs are 100% busy all the time. Each busy-looping thread is 
running on its own CPU. I've been watching top output for 10 minutes, 
the spreading is stable and the threads don't bounce at all.


greetings
Cyrus


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