Re: [PATCH] pooling NUMA scheduler with initial load balancing

From: Erich Focht (
Date: Fri Oct 11 2002 - 03:27:59 EST

On Friday 11 October 2002 09:47, Erich Focht wrote:
> Hi Andrew,
> On Thursday 10 October 2002 19:34, Andrew Theurer wrote:
> > Thanks very much Erich. I did come across another problem here on
> > numa-q. In task_to_steal() there is a divide by cache_decay_ticks, which
> > apparantly is 0 on my system. This may have to do with notsc, but I am
> > not sure. I set cache_decay_ticks to 8, (I cannot boot without using
> > notsc) which is probably not correct, but I can now boot 16 processor
> > numa-q on 2.5.40-mm1 with your patches! I'll get some benchmark results
> > soon.
> oops... This is a bug in 2.5-i386. It means that the O(1) scheduler in
> 2.5 doesn't work well either because it doesn't take into account cache
> coolness. I'll post a fix to LKML in a few minutes.

Sorry, I thought the smp_tune_scheduling() call went lost during the
transition to the new cpu boot scheme. But it's there. And the problem
is indeed "notsc". So you'll have to fix it, I can't.

If you set the cache_decay_ticks to something non-zero, you should
_really_ do this for all the scheduler tests, otherwise your measurements
will not be comparable.


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