Re: [PATCH v4] sched: automated per session task groups

Ingo Molnar
2010-11-29T18:03:55Z

* Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:

> On Mon, 2010-11-29 at 08:27 -0800, Linus Torvalds wrote:
> > On Mon, Nov 29, 2010 at 3:53 AM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> > >
> > > Well we totally re-wrote the cgroup load-balancer in -tip. The thing
> > > currently in -linus is a utter crap because its very strongly serialized
> > > across all cores (some people spend like 25% of their time in there).
> >
> > Well, it seems that the rewrite is more crap than the "utter crap" in
> > current -git. What does that make -tip? Super-utter-crap?
> >
> > Peter - getting the wrong answer quickly is not any better than strong
> > serialization.
>
> I know, from the testing so far we _thought_ it was fairly sane.
> Apparently there's still some work to do.

Btw., i think it shows the conceptual power of Mike's patch that this cgroups
scheduling suckage was exposed so clearly. Previously it took weeks (sometimes
months) for bugs to reach those who are using cgroups.

Thanks,

Ingo