CPU Frequency Governors / Power Schemes in LINUX

This feature is available since 3.4 Kernel.
To see the current speed.
watch grep \"cpu MHz\" /proc/cpuinfo
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq

CPU POWER SCHEMES

Performance   - Full throttle CLOCK
Powersave     - Run the cpu at the minimum frequency
Userspace     - User Specified CLOCK
Ondemand      - Dynamically switch between CPU(s) available if at 95% cpu load
Conservative  - Dynamically switch between CPU(s) available if at 75% load

More Info
https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
https://wiki.archlinux.org/index.php/CPU_Frequency_Scaling

To See current power scheme, below is the command. To modify the current scheme just write the new scheme name to the each CPU scale_governor files.

# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
ondemand
# cat /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
ondemand