Re: [git pull] scheduler fixes

Andrew Morton
2009-01-17T04:41:49Z

On Wed, 14 Jan 2009 21:24:07 +0100 Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:

> On Wed, 2009-01-14 at 12:15 -0800, Andrew Morton wrote:
> > On Sun, 11 Jan 2009 15:43:05 +0100
> > Ingo Molnar <mingo@elte.hu> wrote:
> >
> > > Please pull the latest sched-fixes-for-linus git tree
> >
> > In http://bugzilla.kernel.org/show_bug.cgi?id=12309 the reporters have
> > identified what appears to be a sched-related performance regression.
> > A fairly long-term one - post-2.6.18, perhaps.
> >
> > Testcase code has been added today. Could someone please take a look
> > sometime?
>
> There appear to be two different bug reports in there. One about iowait,
> and one I'm not quite sure what it is about.
>
> The second thing shows some numbers and a test case, but I fail to see
> what the problem is with it.

I had no problem seeing the problem: a gigantic performance regression
in two CPU-scheduler intensive workloads.

I can see some other problems, too.