Ubuntu CPU Frequency Management

Having changed the CPU frequency to ‘Performance’ I decided to go back to ‘On Demand’ so that the processor would not get so hot. My laptop’s Intel Centrino 1.7Ghz processor was heating up to 81 degrees celcius! Intel say that the maximun operating temperature for this processor is 100 degrees, but I think I would rather keep it cool for longer to increase not only the battery life whilst unplugged, but also to increase the lifetime of the processor itself.

It took quite a while to find these commands. One of the reasons I decided to start documenting these Ubuntu tweeks myself 🙂

Modes:

Continuous maximum frequency

sudo cpfreq-selector -g performance

Increases the CPU frequency slowly if needed, and then decreases quickly.

sudo cpfreq-selector -g conservative

Increases and decreases the CPU frequency quickly, on-demand

sudo cpfreq-selector -g ondemand

Powersave sais it all

sudo cpfreq-selector -g powersave

I do not recall how the following operates

sudo cpfreq-selector -g userspace

It is also possible to set particular frequencies manually with multipliers such as 10000 or 12000 but I do not think this is necessary given the options above, not to mention far less intrusive.

Changing the permissions of the cpufreq-selector binary by doing a:

$sudo chmod +s /usr/bin/cpufreq-selector

will allow me to left mouse click on the ‘Frequency Monitor’ and select a mode and speed from a drop-down menu. Very convenient.

However, you can set the suid of the cpufreq-selector executable by running the following in the terminal and confirming upon prompt.

$ sudo dpkg-reconfigure gnome-applets

I will not recommend this as It caused me problems with my own setup. In short, my CPU frequency got stuck on 800Mhz (46%). I recommend using the safer ‘Modes’ posted at the start of this post to control how you wish to use your CPU.