Software name: powertop
Licence: GNU General Public License (GPL) version 2
Developed by: Intel
First of all i have to say i love using Ubuntu, but there are few things annoying me all the time – one of them is power usage.
I got my laptop 27 months ago. For the first 9 months i used Windows XP, which worked flawlessly; but then i started using Ubuntu, and my battery time decreased – ok, this could be the aging of the battery, but still.
Some time ago i found a tool – powertop – which tells you what exactly is eating your battery.
In Ubuntu (7.10 – gutsy) powertop is very easy to install and use – it is in the repositories. So all you have to do is:
sudo apt-get install powertop
and type root password when asked.
Powertop has to be run with root privileges, since it can not acquire all the information using regular privileges.
So open the terminal and write:
sudo powertop
As you can see powertop is far more than you a top utility – it is kind of its low level cousin.
User interface could be divided to 5 parts:
- Upper left part – processor states
The higher the number of the state, the less power is used, and in addition, more time in higher states, even less power is used. It is ideally to be in state 3 and 4 most of the time. Processor states names are: 0-running,1-halt,2-stop-clock,3-sleep. As you can see, the computer i’ve used to make some measurement isn’t doing very well.
– Upper right part – processor states – frequency modes
This processor can run at various frequencies – depending on the current load. I’m sure it is not needed to say this, but still: the lower the frequency, the lower the power usage…
– Main part
Number of wakeups per second and top causes for wakeups. As you can see most of the wakeups is caused by ethernet controller and grafic card driver – which is reasonable. In the time of the measurement, i was listening to internet radio and downloading few torrents 
– Lower part
Suggestions on how to lower your power usage – the suggestions seems logical and very useful, try it for your self!
P.S.:
I tried to install/run powertop on FreeBSD (since i use it on all servers), but it doesn’t seems to be working.
Correct my if I’m wrong…
Tags: Linux, power usage, powertop, unix
