Re: [PATCH 0/5] x86,smp: make ticket spinlock proportional backoffw/ auto tuning

From: Ingo Molnar
Date: Thu Jan 24 2013 - 08:28:36 EST



* Mike Galbraith <bitbucket@xxxxxxxxx> wrote:

> On Thu, 2013-01-10 at 10:31 -0500, Rik van Riel wrote:
> > On 01/10/2013 10:19 AM, Mike Galbraith wrote:
> > > On Tue, 2013-01-08 at 17:26 -0500, Rik van Riel wrote:
> > >
> > >> Please let me know if you manage to break this code in any way,
> > >> so I can fix it...
> > >
> > > I didn't break it, but did let it play with rq->lock contention. Using
> > > cyclictest -Smp99 -i 100 -d 0, with 3 rt tasks for pull_rt_task() to
> > > pull around appears to have been a ~dead heat.
> >
> > Good to hear that the code seems to be robust. It seems to
> > help prevent performance degradation in some workloads, and
> > nobody seems to have found regressions yet.
>
> I had hoped for a bit of positive, but a wash isn't surprising
> given the profile. I tried tbench too, didn't expect to see
> anything at all there, and got that.. so both results are
> positive in that respect.

Ok, that's good.

Rik, mind re-sending the latest series with all the acks and
Reviewed-by's added?

Thanks,

Ingo
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