Re: 2.6.28 - 2.6.29-rc6-git5 regression, p4-clockmod/cpufreq probably

From: Denys Fedoryschenko
Date: Mon Mar 02 2009 - 11:34:17 EST


On Monday 02 March 2009 18:26:21 Sitsofe Wheeler wrote:
> On Mon, Mar 02, 2009 at 06:15:56PM +0200, Denys Fedoryschenko wrote:
> > On Monday 02 March 2009 18:06:59 Matthew Garrett wrote:
> > > On Mon, Mar 02, 2009 at 05:04:59PM +0200, Denys Fedoryschenko wrote:
> > > > On 2.6.29-rc6 (git5 tested also) also shown in dmesg as available,
> > > > but i can't change anything.
> > >
> > > That's deliberate. p4-clockmod is for thermal management, not clock
> > > control (since it doesn't actually do any of that)
> >
> > I know very well it is just throttling, and not real CPU power
> > management. At the end it does job.
> >
> > In my case i used it for testing on "virtual" 113 Mhz video encoding to
> > find out bottleneck on ffmpeg and to compare performance with Blackfin.
>
> If it's just throttling you want can't you do that via
> /proc/acpi/processor/CPU<N>/throttling ...

CPUFreq infrastructure much more powerful.
-d --min <FREQ>
new minimum CPU frequency the governor may select.
-u --max <FREQ>
new maximum CPU frequency the governor may select.
-g --governor <GOV>
new cpufreq governor.

This things you cannot do over inserting values over ACPI. Sure you can
reinvent the wheel, but why?
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