Re: [PATCH] i386 No-Idle-Hz aka Dynamic-Ticks 3

Tony Lindgren
2005-08-04T07:29:36Z

* Con Kolivas <kernel@kolivas.org> [050804 00:16]:
> On Thu, 4 Aug 2005 05:04 pm, Con Kolivas wrote:
> > On Thu, 4 Aug 2005 04:59 pm, Jim MacBaine wrote:
> > > I just borrowed a power meter to see (or not to see) real effects of
> > > dyntick. The difference between static 1000 HZ and dynamic HZ is much
> > > less than I expected, only a very little about noise. With dyntick
> > > disabled at 1000 HZ my laptop needs 31,3 W. With dyntick enabled I
> > > get 29.8 W, the pmstats-0.2 script shows me that the system is at
> > > 35-45 HZ when it is idle.
> > >
> > > The power consumption difference between 250 HZ static and dyntick is
> > > below the noise, so maybe hardly worth all the struggle.
> >
> > That's not the point. We want the power savings without sacrificing the
> > extra ticks if we need them.
>
> Oh but thank you very much for confirming the power savings are around the 5%
> mark. If we don't measure we won't know (and everything else is mental
> masturbation according to Linus ;)).

Dyntick on it's own does not do much. But it allows adding better PM code
later on.

Tony