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

[Peter Zijlstra <peterz@infradead.org>]

On Tue, 2008-04-01 at 13:40 +0200, Andi Kleen wrote:
> Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> writes:
> 
> > Using cpuset, now we can partition the system into multiple sched domains.
> > Then, how about providing different characteristics for each domains?
> 
> Did you actually see much improvement in any relevant workload
> from tweaking these parameters?  If yes what did you change?
> And how much did it gain?
> 
> Ideally the kernel should perform well without much tweaking
> out of the box, simply because most users won't tweak. Adding a 
> lot of such parameters would imply giving up on good defaults which 
> is not a good thing.

>From what I understand they need very aggressive idle balancing; much
more so than what is normally healty.

I can see how something like that can be useful when you have a lot of
very short running tasks. These could pile up on a few cpus and leave
others idle.