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

[Paul Jackson <pj@sgi.com>]

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@sgi.com> 1.940.382.4214