Re: [PATCH] 2.6.0 batch scheduling, HT aware

[Con Kolivas <kernel@kolivas.org>]

On Tue, 23 Dec 2003 14:15, Con Kolivas wrote:
> On Tue, 23 Dec 2003 13:57, Nick Piggin wrote:
> > Con Kolivas wrote:
> > >On Tue, 23 Dec 2003 12:36, Nick Piggin wrote:
> > >>Con Kolivas wrote:
> > >>>I discussed this with Ingo and that's the sort of thing we thought of.
> > >>>Perhaps a relative crossover of 10 dynamic priorities and an absolute
> > >>>crossover of 5 static priorities before things got queued together.
> > >>> This is really only required for the UP HT case.
> > >>
> > >>Well I guess it would still be nice for "SMP HT" as well. Hopefully the
> > >>code can be generic enough that it would just carry over nicely.
> > >
> > >I disagree. I can't think of a real world scenario where 2+ physical
> > > cpus would benefit from this.
> >
> > Well its the same problem. A nice -20 process can still lose 40-55% of
> > its performance to a nice 19 process, a figure of 10% is probably too
> > high and we'd really want it <= 5% like what happens with a single
> > logical processor.
>
> I changed my mind just after I sent that mail. 4 physical cores running
> three nice 20 and one nice -20 task gives the nice -20 task only 25% of the
> total cpu and 25% to each of the nice 20 tasks.

Err that should read 4 logical cores.

Con