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SubjectRe: Scheduler oddness
Excerpts from internet.computing.linux-kernel: 4-Mar-99 Scheduler
oddness by Rui Sousa@grad.physics.s
>
>
> This doesn't happen with four processes running, so I think it's
>
> a problem when running a odd number of processes (greater than the
>
> number of cpu's). Also I don't think it affects UP machines.
>
>

Yes, on SMP machines an advantage is given for processes to stay on the
same CPU (preventing cache thrashing). As such basically with three
processes, you get one on a one cpu, and two processes on the second
CPU. They will CPU jump a little, but it is discouraged by the
scheduler to prevent worse overall preformance. So you endup with one
process getting a lot more CPU time.


Matt

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