How to change the cpufreq as User with Gnome Cpu-Frequency-Scaling-Monitor Applet

by Thomas Janssen — last modified Mar 13, 2008 07:24 AM

— filed under: Laptop

I like to change my CPU Frequency with the 'CPU Frequency Scaling Monitor' Applet in Gnome. I dont like to do su -c cpufreq-set -g powersave all the time. To do this as User we have to change and to add a little bit.

Applicable to Fedora Versions

Fedora 8+

Requirements

AMD Mobile CPU (here it is working with Athlon XP-M 2500)
The 'CPU Frequency Scaling Monitor' Applet loaded in the Gnome-panel (Right klick -> add to panel)

Doing the Work

You will install Software, check your CPU and do the necessary changes to your System. Open a Terminal and become root (su -)

Install the package acpitool:

yum install acpitool

Check if your CPU will support CPU-Frequency-Scaling:

acpitool --cpu

The output should show something like this:
[root@dementia ~]# acpitool --cpu
  CPU type               : mobile AMD Athlon(tm) XP-M 2500+ 
  Min/Max frequency      : 663/1857 MHz
  Current frequency      : 796 MHz
  Frequency governor     : ondemand 
  Freq. scaling driver   : powernow-k7 
  Cache size             : 512 KB
  Bogomips               : 1593.05 
  Processor ID           : 0
  Bus mastering control  : yes
  Power management       : yes
  Throttling control     : no
  Limit interface        : no
  Active C-state         : C0
  C-states (incl. C0)    : 3
  Usage of state C1      : 13320324 (15.9 %)
  Usage of state C2      : 70321617 (84.1 %)

Make the cpufreq-selector useable for Users to change the Frequency governor:

chmod a+s /usr/bin/cpufreq-selector

Check what governors are already loaded:

lsmod | grep freq

The output here is:
cpufreq_ondemand       10317  1 
cpufreq_powersave       5825  0

To get you the same governors on the fly:

modprobe cpufreq_ondemand
modprobe cpufreq_powersave

To make the governors loaded at boot add the following to /etc/rc.local :

modprobe cpufreq_powersave
modprobe cpufreq_ondemand

After the next reboot, you have control over the governors as User without anything to do. No more
su -c 'cpufreq-set -g powersave' in Terminal.

Troubleshooting

How to test

If you left-klick on the 'CPU Frequency Scaling Monitor' Applet, it should look like this:

cpufreqmon-screenshot

Disclaimer

We test this stuff on our own machines, really we do. But you may run into problems, if you do, come to #fedora on irc.freenode.net

Personal tools