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

by thomasj last modified Mar 13, 2008 07:24 AM
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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+


  1. AMD Mobile CPU (here it is working with Athlon XP-M 2500)
  2. 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 -)

  1. Install the package acpitool:
  2. yum install acpitool
  3. Check if your CPU will support CPU-Frequency-Scaling:
  4. 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 %)

  5. Make the cpufreq-selector useable for Users to change the Frequency governor:
  6. chmod a+s /usr/bin/cpufreq-selector
  7. Check what governors are already loaded:
  8. lsmod | grep freq

    The output here is:
    cpufreq_ondemand 10317 1
    cpufreq_powersave 5825 0

  9. To get you the same governors on the fly:
  10. modprobe cpufreq_ondemand
    modprobe cpufreq_powersave
    They will show up immediately on the CPU Frequency Scaling Monitor Applet

  11. To make the governors loaded at boot add the following to /etc/rc.local :
  12. 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.


How to test

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



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

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