CPU Frequency Scaling Framework

The Linux kernel supports CPU performance scaling by means of the CPUFreq (CPU Frequency scaling) subsystem. Changing the CPU frequency can save power consumption (when decreased) or boost performance (when increased). This subsystem navigates through predefined Power-performance states (P-states) and therefore VDDCPU is modified when the CPU frequency is adjusted.

The following governors are available to control the CPU frequency:

To read the governor setting:
# cat /sys/devices/system/cpu/cpufreq/policy0/scaling_governor 
The set of predefined frequencies used by the governor policies is listed in the file system:
# cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies
90000 250000 600000 800000 1000000