Re: BFS vs. mainline scheduler benchmarks and measurements

From: Mike Galbraith
Date: Thu Sep 10 2009 - 07:42:45 EST


On Thu, 2009-09-10 at 13:35 +0200, Jens Axboe wrote:
> On Thu, Sep 10 2009, Mike Galbraith wrote:
> > On Thu, 2009-09-10 at 13:24 +0200, Jens Axboe wrote:
> > > On Thu, Sep 10 2009, Mike Galbraith wrote:
> >
> > > > xmodmap doesn't seem to be running in this sample.
> > >
> > > That's weird, it was definitely running. I did:
> > >
> > > sleep 1; xmodmap .xmodmap-carl
> > >
> > > in one xterm, and then switched to the other and ran the sched_debug
> > > dump. I have to do it this way, as X will not move focus once xmodmap
> > > starts running. It could be that xmodmap is mostly idle, and the real
> > > work is done by Xorg and/or xfwm4 (my window manager).
> >
> > Hm. Ok, I'll crawl over it, see if anything falls out.
>
> That seems to be confirmed with the low context switch rate of the perf
> stat of xmodmap. If I run perf stat -a to get a system wide collection
> for xmodmap, I get:
>
> Performance counter stats for 'xmodmap .xmodmap-carl':
>
> 20112.060925 task-clock-msecs # 1.998 CPUs
> 629360 context-switches # 0.031 M/sec
> 8 CPU-migrations # 0.000 M/sec
> 13489 page-faults # 0.001 M/sec
> <not counted> cycles
> <not counted> instructions
> <not counted> cache-references
> <not counted> cache-misses
>
> 10.067532449 seconds time elapsed
>
> And again, system is idle while this is happening. Can't rule out that
> this is some kind of user space bug of course.

All I'm seeing so far is massive CPU usage for dinky job.

-Mike

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