Re: CPU power management
On Fri, Feb 16, 2007 at 06:22:29PM +0100, Mattia Dongili wrote:
> On Thu, Feb 15, 2007 at 11:26:24PM +0200, Eddy Petri??or wrote:
> > I have installed Debian GNU/kFreeBSD and indeed, the levels are many
> > more than on Linux:
> > sysctl dev.cpu.0.freq_levels
> > Results in a list of frequencies down to 31 MHz. I tried some script I
> > found on the freebsd lists to test the speed of blowfish at various
> > speeds and observed that on my Core 2 Duo that:
> > In conclusion, it would be nice if this code would be ported to Linux, too.
> AFAICT they are mixing freq scaling and throttling.
> See /proc/acpi/processor/CPU/throttling, I have:
> state count: 8
> active state: T0
> *T0: 00%
> T1: 12%
> T2: 25%
> T3: 37%
> T4: 50%
> T5: 62%
> T6: 75%
> T7: 87%
> and the available frequency steps here are 1.83 GHz, 1.33 GHz, 1000 MHz
> This is a Core2 Duo T5600.
> so eg. at 1GHz I can throttle at 880, 750, 630, 500, 380, 250 and
> 130 MHz.
Oh, and let me add (even if probably aready mentioned): throttling
doesn't save any power, it just idles your cpu. Ok, less heat (no fans,
etc) but the real saving is probably unnoticeable.