Re: question on sched-rt group allocation cap: sched_rt_runtime_us

From: Mike Galbraith
Date: Mon Sep 07 2009 - 04:24:22 EST


On Mon, 2009-09-07 at 09:59 +0200, Peter Zijlstra wrote:
> On Sun, 2009-09-06 at 08:32 +0200, Mike Galbraith wrote:
> > On Sat, 2009-09-05 at 19:32 -0700, Ani wrote:
> > > On Sep 5, 3:50 pm, Lucas De Marchi <lucas.de.mar...@xxxxxxxxx> wrote:
> > > >
> > > > Indeed. I've tested this same test program in a single core machine and it
> > > > produces the expected behavior:
> > > >
> > > > rt_runtime_us / rt_period_us % loops executed in SCHED_OTHER
> > > > 95% 4.48%
> > > > 60% 54.84%
> > > > 50% 86.03%
> > > > 40% OTHER completed first
> > > >
> > >
> > > Hmm. This does seem to indicate that there is some kind of
> > > relationship with SMP. So I wonder whether there is a way to turn this
> > > 'RT bandwidth accumulation' heuristic off.
> >
> > No there isn't..
>
> Actually there is, use cpusets to carve the system into partitions.

Yeah, I stand corrected. I tend to think in terms of the dirt simplest
configuration only.

-Mike

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