Re: [patch 6/8] pull RT tasks

From: Steven Rostedt
Date: Fri Oct 19 2007 - 15:44:43 EST



--
On Fri, 19 Oct 2007, Peter Zijlstra wrote:

> > > +
> > > + if (likely(!atomic_read(&rt_overload)))
> > > + return 0;
> >
> > This seems to be the only usage of rt_overload. I'm not sure its worth
> > keeping it around for this.
>
> Ingo just brought up a good point. With large smp (where large is >64)
> this will all suck chunks.
>
> rt_overload will bounce around the system, and the rto_cpumask updates
> might already hurt.
>
> The idea would be to do this per cpuset, these naturally limit the
> migraiton posibilities of tasks and would thus be the natural locality
> to break this data structure.
>

That sounds like a good idea. RT balancing on >64 CPUs should be limited.
Having a bounding cpuset would help.

I'll try to come up with something.

Thanks!

-- Steve

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