Re: BFS vs. mainline scheduler benchmarks and measurements

From: Jens Axboe
Date: Thu Sep 10 2009 - 06:28:43 EST


On Thu, Sep 10 2009, Jens Axboe wrote:
> On Thu, Sep 10 2009, Ingo Molnar wrote:
> >
> > * Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:
> >
> > > On Thu, Sep 10 2009, Ingo Molnar wrote:
> > > >
> > > > * Ingo Molnar <mingo@xxxxxxx> wrote:
> > > >
> > > > > > However, the interactivity problems still remain. Does that
> > > > > > mean it's not a latency issue?
> > > > >
> > > > > It means that Jens's test-app, which demonstrated and helped us
> > > > > fix the issue for him does not help us fix it for you just yet.
> > > >
> > > > Lemme qualify that by saying that Jens's issues are improved not
> > > > fixed [he has not re-run with latest latt.c yet] but not all things
> > > > are fully fixed yet. For example the xmodmap thing sounds
> > > > interesting - could that be a child-runs-first effect?
> > >
> > > I thought so too, so when -tip failed to boot I pulled the patches
> > > from Mike into 2.6.31. It doesn't change anything for xmodmap,
> > > though.
> >
> > Note, you can access just the pristine scheduler patches by checking
> > out and testing tip:sched/core - no need to pull them out and apply.
> >
> > Your crash looks like clocksource related - that's in a separate
> > topic which you can thus isolate if you use sched/core.
>
> I'm building sched/core now and will run the xmodmap test there.

No difference. Then I tried switching NO_NEW_FAIR_SLEEPERS on, and then
I get:

Performance counter stats for 'xmodmap .xmodmap-carl':

9.009137 task-clock-msecs # 0.447 CPUs
18 context-switches # 0.002 M/sec
1 CPU-migrations # 0.000 M/sec
315 page-faults # 0.035 M/sec
<not counted> cycles
<not counted> instructions
<not counted> cache-references
<not counted> cache-misses

0.020167093 seconds time elapsed

Woot!

--
Jens Axboe

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