Re: HELP: cpufreq on HT and/or SMP systems

From: Dominik Brodowski (linux@brodo.de)
Date: Wed Aug 06 2003 - 03:10:46 EST


On Tue, Aug 05, 2003 at 01:16:47PM +0200, Pavel Machek wrote:
> Hi!
>
> > > > AFAIK no SMP systems have voltage/frequency scaling (SpeedStep/PowerNow).
> > > > I've heard that ACPI P-states works on SMP, but if it's not doing
> > > > voltage/frequency scaling then I don't know what it's doing.
> > >
> > > I've got an ABit VP6 (VIA686, dual P3), and the processors speed and
> > > voltage can be set in the BIOS. Does it count ?
> >
> > I meant dynamic voltage/frequency scaling, so that doesn't count.
>
> If his bios can change voltage/frequency, kernel can probably do the
> same. So his hardware probably can be supported by cpufreq.

The cpufreq core supports SMP. But only a few SMP capable CPUs offer cpu
frequency and/or voltage scaling. Those who do (e.g. P4/Xeon, UltraSparc
variants, and some ARM processors, IIRC) are well supported by cpufreq.

        Dominik
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