Re: [tip:sched/core] sched: Keep kthreads at default priority

From: Martin Steigerwald
Date: Sat Sep 12 2009 - 07:48:45 EST


Am Mittwoch 09 September 2009 schrieb Mike Galbraith:
> On Wed, 2009-09-09 at 19:06 +0200, Peter Zijlstra wrote:
> > On Wed, 2009-09-09 at 09:55 -0700, Dmitry Torokhov wrote:
> > > On Wed, Sep 09, 2009 at 03:37:34PM +0000, tip-bot for Mike Galbraith
wrote:
> > > > diff --git a/kernel/kthread.c b/kernel/kthread.c
> > > > index eb8751a..5fe7099 100644
> > > > --- a/kernel/kthread.c
> > > > +++ b/kernel/kthread.c
> > > > @@ -16,8 +16,6 @@
> > > > #include <linux/mutex.h>
> > > > #include <trace/events/sched.h>
> > > >
> > > > -#define KTHREAD_NICE_LEVEL (-5)
> > > > -
> > >
> > > Why don't we just redefine it to 0? We may find out later that we'd
> > > still prefer to have kernel threads have boost.
> >
> > Seems sensible, also the traditional reasoning behind this nice level
> > is that kernel threads do work on behalf of multiple tasks. Its a
> > kind of prio ceiling thing.
>
> True. None of our current threads are heavy enough to matter much.

Does it make sense to have this as a tunable? Where does it matter? Server
workloads?

(Oh no, not another tunable I can hear you yell;-).

--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7

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