Re: [PATCH 1/2] Customize sched domain via cpuset

From: Paul Jackson
Date: Thu Apr 03 2008 - 09:14:24 EST


H.Seto wrote:
> I believe there are quite technical reasons why we have no "idle_map."

I would not advocate a single system wide cpumask of idle CPUs. As
Peter Zijlstra notes in a follow up post, that's too hot a cache line
and clearly doesn't scale.

But I would think it would be ok to have a separate cpumask per node,
that marked just the node-local CPUs. We have other per-node data
already. If we only support this optional load balancing level across
the other CPUs on the same node (or smaller domains, such as the cores
in a package), that should work, shouldn't it?

> so I'll update my patch to take levels, getting in your suggestion.

If you see a good solution here that you can provide, good. But if my
brain storming ideas have problems, don't hesitate to object to them.

--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@xxxxxxx> 1.940.382.4214
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