Tuesday, July 21, 2009

Using PowerTop to save Battery Power (Part 1)

I was playing with PowerTop. Powertop is a tool to help you identify applications and programs that uses power even when the computer is idle. According to LessWatts.org, Powertop has these four basic goals:

  • Show how well your system is using the various hardware power-saving features
  • Show you the culprit software components that are preventing optimal usage of your hardware power savings
  • Help Linux developers test their application and achieve optimal behavior
  • Provide you with tuning suggestions to achieve low power consumption

So much for the introduction.
To install powertop, just use
# apt-get install powertop
# yum install powertop
It should be found in most distro.

# powertop
I'm pretty new to the powertop, so I follow the recommendation.
To make some of the recommedendation permanent, I've placed the configuration in the /etc/acpi/battery.d diretory and name is 16-optimisation.sh.

# cd /etc/acpi/battery.d # touch 16.optimsation.sh
# chmod 755 16.optimsation.sh
# vim 16-optimisation.sh

echo 1500 > /proc/sys/vm/dirty_writeback_centisecs
echo 5 > /proc/sys/vm/laptop_mode
iwpriv eth1 set_power 5

hal-disable-polling --device /dev/scd0

To continue Using PowerTop to save Battery Power (Part 2)


Kim said...

Great post! Thank you espescially for showing me how to make the changes permanent. But shouldn't one write a second script that reverses the changes once the laptop isn't running on battery power anymore? How would one do that?

kittycool said...

Hi Kim,

Thank you for the comments.

From my understanding, we can put some setting back at /etc/acpi/ac.d and reverses the changes once the laptop isn't running on battery power.