From: Michal Szymanski <msz@astrouw.edu.pl>
To: SMP list <linux-smp@vger.kernel.org>
Subject: unbalanced load
Date: Wed, 18 May 2005 22:48:13 +0200 [thread overview]
Message-ID: <20050518204813.GA10028@astrouw.edu.pl> (raw)
Hi,
On 2.6 SMP kernels (running on multi-cpu machines) one can see the
effect called "Light but Unbalanced Load" by Rick Lindsley in his
article "What's New in the 2.6 Scheduler?"
(http://www.linuxjournal.com/article/7178)
If, say, 3 processes run on a dual-cpu machine, one of them tends to be
bound to one processor, taking 99.9% of cpu time, while two other run
on the second processor, dividing its time more or less 50%-50%
I think this might be considered reasonable (although if the tasks
are not of the same user, it might be unfair) if all the tasks have the
same 'nice level'.
But, I have noticed that even if one of the tasks is niced and two other
- not, it happens that it is the niced process that occupies one cpu
alone, getting 99.9% of the processor time. This seems to be explicitly
contrary to what nice-ing the jobs should do.
Is this 'affinity' or 'cpu-binding' issue controllable somehow (by
setting some kernel parameters, for example)?
thanks in advance for hints,
regards, Michal.
--
Michal Szymanski (msz at astrouw dot edu dot pl)
Warsaw University Observatory, Warszawa, POLAND
reply other threads:[~2005-05-18 20:48 UTC|newest]
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