Re: BFS vs. mainline scheduler benchmarks and measurements

[Ingo Molnar]

* Bret Towe <magnade@xxxxxxxxx> wrote:

> On Thu, Sep 10, 2009 at 9:26 AM, Ingo Molnar <mingo@xxxxxxx> wrote:
> >
> > * Bret Towe <magnade@xxxxxxxxx> wrote:
> >
> >> On Thu, Sep 10, 2009 at 9:05 AM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> >> > On Thu, 2009-09-10 at 09:02 -0700, Bret Towe wrote:
> >> >>
> >> >> thanks to this thread and others I've seen several kernel tunables
> >> >> that can effect how the scheduler performs/acts
> >> >> but what I don't see after a bit of looking is where all these are
> >> >> documented
> >> >> perhaps thats also part of the reason there are unhappy people with
> >> >> the current code in the kernel just because they don't know how
> >> >> to tune it for their workload
> >> >
> >> > The thing is, ideally they should not need to poke at these.
> >> > These knobs are under CONFIG_SCHED_DEBUG, and that is exactly
> >> > what they are for.
> >>
> >> even then I would think they should be documented so people can
> >> find out what item is hurting their workload so they can better
> >> report the bug no?
> >
> > Would be happy to apply such documentation patches. You could also
> > help start adding a 'scheduler performance' wiki portion to
> > perf.wiki.kernel.org, if you have time for that.
> 
> time isn't so much the issue but not having any clue as to what 
> any of the options do

One approach would be to list them in an email in this thread with 
question marks and let people here fill them in - then help by 
organizing and prettifying the result on the wiki.

Asking for clarifications when an explanation is unclear is also 
helpful - those who write this code are not the best people to judge 
whether technical descriptions are understandable enough.

	Ingo
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