Re: scheduler vs hardware? (was Re: another i7 (linux) bug?)

Luca Zini
2010-01-22T20:15:07Z

vanilla 33-rc5 runs ok:
with nice set to -20
real 0m8.649s
user 0m8.600s
sys 0m0.030s

with nice set to 19:
real 0m8.658s
user 0m8.600s
sys 0m0.040s

thank you!
Luca

On Friday 22 January 2010 08:19:18 am Mike Galbraith wrote:
> > if I run a cpu intensive process with the lowest priority (19
> > from man nice) I obtain much better performance that with the
> > highest priority available (-20 from man nice).
> >
> > For example the same file is processed by lame in 8.7 seconds
> > at the lowest priority, and in 12 seconds at the highest
> > priority. Before posting a bug I wold like to understand if
> > this is a problem related to the i7 mobile (my processor is a
> > i7 Q720).
> >
> > As far as I tested on the same laptop series (dell studio 15),
> > with the same kernel this problem does not exists.
>
> So you only see this on the i7. That's odd. Can you try 33-rc5?
>
> Posting a reliable reproducer would be nice. It'd also be nice to see
> what all is running when you see this, and where.
>
> -Mike
>