Re: [PATCH 0/2] fix the itimer regression (BZ 12618)

From: Lin Ming
Date: Mon Feb 09 2009 - 01:48:58 EST


On Fri, 2009-02-06 at 23:18 +0800, Ingo Molnar wrote:
> * Zhang, Yanmin <yanmin_zhang@xxxxxxxxxxxxxxx> wrote:
>
> > On Thu, 2009-02-05 at 13:06 +0100, Ingo Molnar wrote:
> > > * Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> > >
> > > > This should hopefully address all the itimer borkage.
> > >
> > > Applied to tip:timers/urgent, thanks Peter!
> > >
> > > Yanmin: could you check hacbench_pth with latest tip/master, do
> > > these fixes resolve that 3% regression you reported?
> >
> > Lin Ming tested it and hackbench_pth/volanoMark regression all disappear.
> > But oltp has a regression. We think oltp new regression isn't related to
> > the patch. Ming is investigating it.
>
> Potential suspects for oltp regression would be:
>
> 3d39870: sched_rt: don't use first_cpu on cpumask created with cpumask_and
> a571bbe: sched: fix buddie group latency
> a9f3e2b: sched: clear buddies more aggressively
> 1596e29: sched: symmetric sync vs avg_overlap
> d942fb6: sched: fix sync wakeups

I tested the latest tip-master branch.
After reverting "d942fb6: sched: fix sync wakeups", the oltp regression
on the 8cores Stockley machine is mostly fixed.

On another 4*4 cores Tigerton machine, oltp has more than 10% regression
with 2.6.29-rc4 compared with 2.6.29-rc3.

Lin Ming

>
> Ingo

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