Saving Battery Life in Ubuntu

21 06 2007

This post is available at my new blog The IT Report:




5 responses

21 06 2007

Nice article, thank you. I have a few things to add.

Step 1. about the governor applet, it seems that the “on demand” would be the best for power saving. At least, that’s what Intel thinks.

On step 2., there is a nice Gnome temperature applet for it. You can monitor CPU and hard disk temperature.

For your item 5. there is a typo 😉 it is not System -> Administrations -> Sessions, but Services at the end.

On the first link above, there are lots of information about what services drains power. CUPS is one of them 😉 so step 5 was a good advise! The patch and relevant kernel pointed on the Intel/PowerTop web site should all be included in Ubuntu Gutsy Gibbon. For the time being, if you are on Ubuntu 7.04, you can either deactivate the service if you do not use it, or quit it when not using it. A bit cumbersome, but it is only needed when you are on battery…

If you are interested with power management on Linux or Ubuntu, check the environment category on my blog. There are some useful resources, e.g. if you have a Dell laptop and want to dim the screen automatically…

21 06 2007

Huygens – thanks for the tips! I’ve updated my blog accordingly. You posted some good links, and they will definitely help us out!

You noted that Intel thinks we should use “on demand.” This is correct if you want the perfect balance between performance and battery because On Demand changes the frequency based on how heavy your processor is being used. When you’re running an intensive app, on demand will scale your CPU to a higher frequency, and when you are idle it will clock down. This is called SpeedStep in Intel terminology.

Thanks again for your helpful insight!

21 06 2007

Oopsie, I am sorry but that was the wrong link about on_demand 😉

I really meant that Intel was stating that on_demand was better also for power management, so not only for performance.
Check in the FAQ, the entry named: Why is “ondemand” kernel’s CPU governor more efficient than the “conservative” one (or than manually lowering CPU freq)?.
Their answer is:

At lower freqs, your CPU may take more time to execute heavy tasks, so will spend less time in idle (power saving) state. The “ondemand” governor solves this by elevating the CPU to full speed when needed, so it can go back to idle state quickly.

21 06 2007
Intel + Linux = More Performance, Better Battery Life? « Mohammad Azimi

[…] If you want to start increasing your battery life before Gutsy Gibbon is released, check out this blog. […]

4 07 2007

“Run Less Programs?” Perhaps you meant run *fewer* programs.

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