Re: [patch] Re: scheduler oddity [bug?]

From: Peter Zijlstra
Date: Mon Mar 09 2009 - 09:46:50 EST


On Mon, 2009-03-09 at 14:37 +0100, Mike Galbraith wrote:
> On Mon, 2009-03-09 at 14:16 +0100, Mike Galbraith wrote:
> > On Mon, 2009-03-09 at 12:04 +0100, Peter Zijlstra wrote:
> >
> > > OK, talked a bit with Ingo, the reason you're doing is that avg_overlap
> > > can easily grow stale.. I can see that happen indeed.
> > >
> > > So the 'perfect' thing would be a task-runtime decay, barring that the
> > > preemption thing seems a sane enough hart-beat of a task.
> > >
> > > How does the below look to you?
> >
> > Other than the fact that the test for sync reject is currently
> > avg_overlap > sysctl_sched_migration_cost, looks fine to me. Having it
> > capped at the boundary is probably the better way to go.
>
> Heh, doesn't _quite_ work though. The little bugger now hovers just
> under :-/

> se.avg_overlap : 0.499993

Right, update_avg()'s >>3 and the off-by-one you spotted.

I recon stuff works better with a 2* added? After that I guess its
praying sysbench still works.. :-)

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