Re: BFS vs. mainline scheduler benchmarks and measurements

From: Jens Axboe
Date: Thu Sep 10 2009 - 07:24:51 EST


On Thu, Sep 10 2009, Mike Galbraith wrote:
> On Thu, 2009-09-10 at 13:09 +0200, Jens Axboe wrote:
> > On Thu, Sep 10 2009, Mike Galbraith wrote:
> > > On Thu, 2009-09-10 at 12:28 +0200, Jens Axboe wrote:
> > >
> > > > 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!
> > >
> > > Something is very seriously hosed on that box... clock?
> >
> > model name : Genuine Intel(R) CPU T2400 @ 1.83GHz
> >
> > Throttles down to 1.00GHz when idle.
> >
> > > Can you turn it back on, and do..
> >
> > I guess you mean turn NEW_FAIR_SLEEPERS back on, correct?
> >
> > > while sleep .1; do cat /proc/sched_debug >> foo; done
> > > ..on one core, and (quickly;) xmodmap .xmodmap-carl, then send me a few
> > > seconds worth (gzipped up) to eyeball?
> >
> > Attached.
>
> 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).

--
Jens Axboe

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