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From: Carsten Aulbert <carsten.aulbert@aei.mpg.de>
To: linux-kernel@vger.kernel.org
Cc: Henning Fehrmann <henning.fehrmann@aei.mpg.de>
Subject: Idle core on overloaded CPU?
Date: Thu, 23 Oct 2008 14:12:32 +0200	[thread overview]
Message-ID: <49006A30.7030208@aei.mpg.de> (raw)

Hi,

on Intel X3220 CPU based systems (4 physical cores) I came across the
following thing (Debian etch, with vanilla kernel 2.6.25.9):

starting the following:
$ screen -d -m stress -c 2
$ nice -19 screen -d -m stress -c 4

This causes two cores to be 100% busy in user state and one core to be
busy in 100% nice state. However, the remaining core is idle. Even
watching it over longer stretches of time, the situation remains static.

I guess it's a kernel misconfiguration on my part (config available here:
https://n0.aei.uni-hannover.de/linux/kernel/config-2.6.25.9-nodes
), but if not could this be a scheduling bug?

Thanks for any hint

Cheers

Carsten

                 reply	other threads:[~2008-10-23 12:38 UTC|newest]

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