Save Power with Linux

Intel has created a new website helping Linux users to reduce the power consumption of a computer (especially useful for laptops): Flash Electricity On this page many tips and tools helping to save electricity (and therefore get longer battery life) are provided. During the next days (weeks?) I will do some tests and improvements on my laptop and tell you about the results.

Today I would like to start with the installation of PowerTOP, a tool helping to find out how badly the computer is configured and which software is consuming most of the power. It can be downloaded from Unfortunately it has not yet been integrated into the Ubuntu package system and there are currently no .deb files available. Thus you have to download and compile it yourself to install it – but that’s easy:

  1. Download it.
  2. Unpack it by typing tar -xzf powertop-1.8.tar.gz in a terminal.
  3. Enter the folder: cd powertop-1.8
  4. On Debian/Ubuntu install sudo apt-get install libncursesw5-dev
  5. Type make. The program compiles, this is done in a few seconds. If you get the following error
    /usr/bin/ld: cannot find -lncursesw
    collect2: ld returned 1 exit status
    make: *** [powertop] Error 1

    you have forgotten to install libncursesw5-dev in the previous step. Do it and retype make.
  6. Type sudo make install (it is important that this be done as root/sudo!).
  7. Start PowerTop sudo powertop

After being started, the program will tell you how often the CPU is woken up per second and give suggestions how you can improve the situation. In my case there are currently between 400 and 600 wakeups per second – in the best case three (3) are enough. Thus, my computer is wasting a lot of energy.
To achieve good results, a kernel of version 2.6.21 or later has to be installed. This also activates all functionalities of PowerTop.

In the next post we will install the new kernel on Ubuntu Feisty.

One Response to “Save Power with Linux”

  1. clem sagt:

    Hello Dominik,
    as always, your posts about the Linux world are interesting. As soon as I have some time, I’ll try this out.

    By the way, I tried to install Ubuntu Feisty on my cousin’s laptop, which is a very recent HP Pavillion. Unfortunately, I encountered many problems: the two main drawbacks are the wifi, which is not recognised, and the graphic card, whose resolution is not set correctly (even after installing the new nvidia drivers). I was rather frustrated by these problems, because I never encountered anything like this with my laptop. I think that they may be caused by the hardware of his laptop, which is very recent and thus probably not yet supported by Linux. Hopefully, it’ll be better with the new Ubuntu release, which is due on October 18 (if I am not wrong).

    Well, wish you all the best in Montréal! See you!

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