There are plenty of things that I love about Linux, but when it comes to maximizing battery life performance, there is very little to desire. On the frontend, you might be running very few applications, but unknown to you, there are actually plenty of applications running in the backend that are quietly draining away your battery. Compiz, workspace, dock are few such examples. As a result, a battery that used to last 3 hours can only last for 2 hours (or less) now.
So what can you do about it?
PowerTOP is an application that allows you to view information about programs that are misbehaving while your computer is idle. With this information, you can then make changes and optimize your computer to squeeze more juice out of your laptop battery.
For Ubuntu and Debian based system
sudo apt-get install powertop
In the terminal, type
PowerTOP runs itself inside the terminal, so don’t expect a fanciful GUI here.
On the top of the screen, you can see the two columns showing the C-states and P-states.
The C-state refers to the idle state where your CPU is not doing anything. The higher C-state the CPU is running at, the better it is.
On the other hand, the P-state shows the operational state, or the frequency the CPU is running at most of the time. The lower frequency the CPU runs, the lesser power it will require. From the screenshot above, you can see that my laptop is running at C3 and 800MHz most of the time. (More info on the C-states and P-states can be found here)
At the bottom half is where you can see the applications that are actively running in the background. The number of wakeup refers to the number of time the application refreshes itself to check for instruction. The fewer wakeup an application makes, the better it is.
It is pretty useless if you know the cause of the problem, but not the solution to it. One thing that impresses me in PowerTOP is that it provides improvement suggestions as well as the instruction to implement the solution. It even comes with a shortcut key for those who are not familiar with the command line.
For example, in my laptop, PowerTOP detects that the USB drive is taking up plenty of resources and it suggested me to enable the USB auto-suspend mode. Even though I have completely no idea on how to do that in the terminal, I can simply press U on my keyboard and get PowerTOP to do the job for me.
Isn’t that cool!
Once you have resolved one issue, PowerTOP will continue to prompt you for the next issue, until it resolves all the issues that it can find.
If you are already power-managing your laptop, PowerTOP might not be able to improve your battery life to a great extent, but for those casual users who have paid no attention to such detail in the past, I am sure PowerTOP will be able to help you to get the most out of your battery; provided your battery is still functional.