Re: BFS vs. mainline scheduler benchmarks and measurements

From: Ingo Molnar
Date: Thu Sep 10 2009 - 16:43:10 EST



* Martin Steigerwald <Martin@xxxxxxxxxxxx> wrote:

> Am Donnerstag 10 September 2009 schrieb Ingo Molnar:
> > * Martin Steigerwald <Martin@xxxxxxxxxxxx> wrote:
> > > Am Mittwoch 09 September 2009 schrieb Peter Zijlstra:
> > > > On Wed, 2009-09-09 at 12:05 +0300, Nikos Chantziaras wrote:
> > > > > Thank you for mentioning min_granularity. After:
> > > > >
> > > > > echo 10000000 > /proc/sys/kernel/sched_latency_ns
> > > > > echo 2000000 > /proc/sys/kernel/sched_min_granularity_ns
> > > >
> > > > You might also want to do:
> > > >
> > > > echo 2000000 > /proc/sys/kernel/sched_wakeup_granularity_ns
> > > >
> > > > That affects when a newly woken task will preempt an already
> > > > running task.
> > >
> > > Heh that scheduler thing again... and unfortunately Col appearing
> > > to feel hurt while I am think that Ingo is honest on his offer on
> > > collaboration...
> > >
> > > While it makes fun playing with that numbers and indeed
> > > experiencing subjectively a more fluid deskopt how about just a
> > >
> > > echo "This is a f* desktop!" > /proc/sys/kernel/sched_workload
> >
> > No need to do that, that's supposed to be the default :-) The knobs
> > are really just there to help us make it even more so - i.e. you
> > dont need to tune them. But it really relies on people helping us
> > out and tell us which combinations work best ...
>
> Well currently I have:
>
> shambhala:/proc/sys/kernel> grep "" sched_latency_ns
> sched_min_granularity_ns sched_wakeup_granularity_ns
> sched_latency_ns:100000
> sched_min_granularity_ns:200000
> sched_wakeup_granularity_ns:0
>
> And this give me *a completely different* desktop experience.

what is /debug/sched_features - is NO_NEW_FAIR_SLEEPERS set? If not
set yet then try it:

echo NO_NEW_FAIR_SLEEPERS > /debug/sched_features

that too might make things more fluid.

Ingo
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