Re: Sched_autogroup and niced processes

From: Ingo Molnar
Date: Fri May 13 2011 - 05:05:53 EST



* Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:

> On Fri, 2011-05-13 at 10:22 +0200, Ingo Molnar wrote:
> > * Mike Galbraith <efault@xxxxxx> wrote:
> >
> > > > > time make -j12 # with seti@home running
> > > > > real 4m16.753s
> > > > > user 10m33.770s
> > > > > sys 1m39.710s
> > > > >
> > > > > time make -j12 # without seti@home running
> > > > > real 2m12.480s
> > > > > user 10m11.580s
> > > > > sys 1m39.980s
> >
> > I think the practical question here is to make seti@home run more idle.
> >
> > Are there some magic cgroup commands you could recommend for that?
>
> Yong already did.

Oh, indeed, stupid me. This teaches me to not stop at the first paragraph of
interesting looking emails ;-)

Could we somehow automate this:

> echo 19 > /proc/'pid of seti@home'/autogroup

and split off nice 19 tasks into separate groups and lower the group's
priority?

That would fit into the general principle of auto-sched as well.

Another thing we could do is to lower the priority of a cgroup if it *only*
runs reniced tasks. I.e. track the 'maximum priority' of cgroups and propagate
that to their weight.

This way renicing within cgroups will be more powerful and people do not have
to muck with cgroup details.

Thanks,

Ingo
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