Re: CFS Bandwidth Control - Test results of cgroups tasks pinned vsunpinnede

From: Srivatsa Vaddagiri
Date: Tue Sep 13 2011 - 14:35:17 EST


* Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> [2011-09-13 20:30:46]:

> On Tue, 2011-09-13 at 23:58 +0530, Srivatsa Vaddagiri wrote:
> > * Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> [2011-09-13 20:19:55]:
> >
> > > On Tue, 2011-09-13 at 23:24 +0530, Srivatsa Vaddagiri wrote:
> > > > We saw considerably high migration count on latest tip compared to
> > > > previous kernels. Kamalesh, can you please post the migration count
> > > > data?
> > >
> > > Hrmm, yes this looks horrid.. even without cgroup crap, something's funny.
> >
> > Yes ..we could visualize that very much in top o/p .. A task's cpu would keep
> > changing *every* screen refresh (refreshed every 0.5 sec that too!).
> >
> > We didn't see that with older kernels ..Kamalesh is planning to do a
> > git bisect and see which commit lead to this "mad" hopping ..
>
> Awesome, thanks! Btw, what is 'older'? 3.0?

We went back all the way upto 2.6.32! I think 2.6.38 and 2.6.39 were
pretty stable ..I don't have the migration count data with me readily. I
will let Kamalesh post that info soon.

- vatsa

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