Re: CFS review

From: Matt Mackall
Date: Thu Aug 02 2007 - 23:04:43 EST


On Wed, Aug 01, 2007 at 01:22:29PM +0200, Ingo Molnar wrote:
>
> * Roman Zippel <zippel@xxxxxxxxxxxxxx> wrote:
>
> > [...] e.g. in this example there are three tasks that run only for
> > about 1ms every 3ms, but they get far more time than should have
> > gotten fairly:
> >
> > 4544 roman 20 0 1796 520 432 S 32.1 0.4 0:21.08 lt
> > 4545 roman 20 0 1796 344 256 R 32.1 0.3 0:21.07 lt
> > 4546 roman 20 0 1796 344 256 R 31.7 0.3 0:21.07 lt
> > 4547 roman 20 0 1532 272 216 R 3.3 0.2 0:01.94 l
>
> Mike and me have managed to reproduce similarly looking 'top' output,
> but it takes some effort: we had to deliberately run a non-TSC
> sched_clock(), CONFIG_HZ=100, !CONFIG_NO_HZ and !CONFIG_HIGH_RES_TIMERS.

..which is pretty much the state of play for lots of non-x86 hardware.

--
Mathematics is the supreme nostalgia of our time.
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