Before selecting and configuring a CPUfreq governor, you need to add the appropriate CPUfreq driver first.
Procedure 3.1. How to Add a CPUfreq Driver
Use the following command to view which CPUfreq drivers are available for your system:
modprobe to add the appropriate CPUfreq driver.
When using the above command, be sure to remove the
.ko filename suffix.
When choosing an appropriate CPUfreq driver, always choose
p4-clockmod. While using the
p4-clockmod driver reduces the clock frequency of a CPU, it does not reduce the voltage.
acpi-cpufreq, on the other hand, reduces voltage along with CPU clock frequency, allowing less power consumption and heat output for each unit reduction in performance.
Once the CPUfreq driver is set up, you can view which governor the system is currently using with:
You can also view which governors are available for use for a specific CPU using:
Some CPUfreq governors may not be available for you to use. In this case, use
modprobe to add the necessary kernel modules that enable the specific CPUfreq governor you wish to use. These kernel modules are available in
Procedure 3.2. Enabling a CPUfreq Governor
If a specific governor is not listed as available for your CPU, use
modprobe to enable the governor you wish to use. For example, if the
ondemand governor is not available for your CPU, use the following command:
Once a governor is listed as available for your CPU, you can enable it using:
[governor] > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor