Changing the CPU Frequency to Conserve Power

The Linux kernel CPUFreq subsystem provides dynamic CPU frequency scaling (also known as CPU throttling) where a processor is run at less than the maximum frequency to conserve power.

To change the CPU frequency of the DT78xx module, you must edit the file /etc/default/cpufequtils (or create it if it does not exist) by performing the following steps:

1. Open the network configuration file using an editor of your choosing. The following example uses the vi editor:

# vi /etc/default/cpufrequtils

2. Specify the governor to use at boot time with the GOVERNOR variable. Valid values (found in /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors) are as follows:

• userspace  - Allows you can set or get the CPU frequency using cpufreq=set or cpufreq-info.

• conservative - Gradually increases or decreases the CPU frequency depending on the current usage.

• powersave - Sets the CPU frequency to the minimum value to save power.

• ondemand - Rapidly increases or decreases the CPU frequency based on the usage.

• performance - Sets the CPU frequency to the maximum value.

 The following example sets the CPU frequency to the minimum value to save power:

 GOVERNOR="powersave"

3. Save and close the file.