Re: [patch 2/3] sched: fix minimum power returned byupdate_cpu_power()
From: Suresh Siddha
Date: Mon Aug 16 2010 - 13:38:32 EST
On Mon, 2010-08-16 at 00:50 -0700, Peter Zijlstra wrote:
> On Fri, 2010-08-13 at 12:45 -0700, Suresh Siddha wrote:
> > plain text document attachment (fix_update_cpu_power.patch)
> > Default cpu_power needs to be multiples of SCHED_LOAD_SCALE and not '1'.
> > Fix it.
> >
> > Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
> > ---
> > kernel/sched_fair.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > Index: tree/kernel/sched_fair.c
> > ===================================================================
> > --- tree.orig/kernel/sched_fair.c
> > +++ tree/kernel/sched_fair.c
> > @@ -2309,7 +2309,7 @@ static void update_cpu_power(struct sche
> > power >>= SCHED_LOAD_SHIFT;
> >
> > if (!power)
> > - power = 1;
> > + power = SCHED_LOAD_SCALE;
> >
>
> smt_power freq_power rt_power
> power = SCHED_LOAD_SCALE * ---------- * ---------- * ----------
> LOAD_SCALE LOAD_SCALE LOAD_SCALE
>
> Which, in the above case ends up being 0, so how does resetting it back
> to LOAD_SCALE make sense?
hmm, true, but I thought I saw some load balancing code which was
depending on SCHED_LOAD_SCALE value. Ignore this for now. Will get back
to you if this indeed is a problem.
thanks,
suresh
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