Subject: Re: [patch] Re: scheduler oddity [bug?]
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Mike Galbraith <efault@gmx.de>
Cc: Ingo Molnar <mingo@elte.hu>, Balazs Scheidler <bazsi@balabit.hu>,
       linux-kernel@vger.kernel.org, Willy Tarreau <w@1wt.eu>
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Date: Mon, 09 Mar 2009 14:46:29 +0100
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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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