[ltp] Speed stepping below 798000 Hz

[Noah Dain]

On 10/8/05, Alex Polite <notmyprivateemail@gmail.com> wrote:
> Hi again.
>
> Fiddling around with the config of my new X30.
>
> I've enabled speed stepping. Think I've got it all right in the
> kernel. I'm using powernowd to control the frequency. Problem is I
> never get below 798000 Hz, even when the processor is idling.
>
> cat /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state
> 1197000 152464
> 798000 1042210
>
> Is this the best I can hope for? Does the processor of the X30 only
> have two speed "stops", or can I get it to go slower than 798000 Hz.
>
> alex
>
> --
> Alex Polite
> http://flosspick.org - finding the right open source
> --
> The linux-thinkpad mailing list home page is at:
> http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad
>
what does:
$ cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq

tell you?  That should be the lowest speed supported (either by
hardware or kernel).

you can also check /sys/devices/system/cpu/cpu0/cpufreq/
    scaling_min_freq (should be the minimum)
    scaling_available_frequencies (should list all available speeds)

two ideas:
    1) you've buggered with the powernowd configuration
    2) possibly you have something eating cpu time, and thus keeping
the speed a step above idle(?)

or you can try this horrid little shell script i wrote to mess with
cpu speed without a user-space governor running.  Just running it
lists some info, and attempts to change nothing.


#!/bin/sh

GOVPATH=3D"/sys/devices/system/cpu/cpu0/cpufreq/"
GOVERNOR=3D"${GOVPATH}scaling_governor"
GOVSTAT=3D`cat ${GOVPATH}scaling_governor`
GOVAVAIL=3D`cat ${GOVPATH}scaling_available_governors`
FREQAVAIL=3D`cat ${GOVPATH}scaling_available_frequencies`

case "$1" in
    performance)
        echo $1 > $GOVERNOR
        echo "setting cpu governor to: `cat ${GOVPATH}scaling_governor`"
        ;;
    powersave)
        echo $1 > $GOVERNOR
        echo "setting cpu governor to: `cat ${GOVPATH}scaling_governor`"
        ;;
    ondemand)
        echo $1 > $GOVERNOR
        echo "setting cpu governor to: `cat ${GOVPATH}scaling_governor`"
        ;;
    userspace)
        echo $1 > $GOVERNOR
        echo "setting cpu governor to: `cat ${GOVPATH}scaling_governor`"
        ;;
    *)
        echo need option of: ${GOVAVAIL}
        echo
        echo current governor is: `cat ${GOVPATH}scaling_governor`
        echo current speed is: `cat ${GOVPATH}scaling_cur_freq`
        echo supported frequencies: ${FREQAVAIL}
        ;;
esac

# end script

--
Noah Dain
noahdain@gmail.com