Re: Power consumption HZ100, HZ250, HZ1000: new numbers

Lee Revell
2005-07-30T18:06:13Z

On Sat, 2005-07-30 at 12:06 +0200, Marc Ballarin wrote:
> On Fri, 29 Jul 2005 19:15:42 -0400
> Lee Revell <rlrevell@joe-job.com> wrote:
>
> >
> > What kind of results do you get with a more realistic setup, like
> > running KDE or Gnome OOTB?
> >
>
> Here are results with KDE running.
>
> - no peripherals attached, i.e. truly mobile setup.
> - all modules loaded
> - klaptopdaemon disabled in order to eliminate competition in polling the
> already slow battery controller
> - furthermore, I found that artsd prevents entering C3 and generally
> increases power consumption (ALSA, snd_intel8x0)
> - voltage is 16.5V

> HZ=100: HZ=1000: DIFF:
>
> 1) averages:
>
> backlight off, arstd off:
> 637.17 679.67 42.5

> backlight off, artsd on:
> 799.46 806.13 6.67

So it looks like artsd wastes way more power DMAing a bunch of silent
pages to the sound card than HZ=1000.

There's nothing the ALSA layer can do about this, it's a KDE bug.

I think this is a good argument for leaving HZ at 1000 until some of
these userspace bugs are fixed.

Lee