Matthias asked me the other day if I could do a longitudinal study of power consumption of Fedora. I used my new T61 with Intel graphics for the study as this is the machine I use every day. Anything older than F8 failed to boot (SATA?) and so the results are a little short. I will repeat the same test on some older hardware when I have a spare couple of hours next week.
So, what can you take from this graph:
- When suspend works well, it uses hardly any power
- Playing high fps-movies fullscreen is bad for your battery.
- Anything involving large amounts of hard-drive and CDROM accesses will drain your battery.
- You can save about 4W by turning your brightness down, and 10W by turning the panel off completely.
- As a trend, linux seems to be getting better at this powersaving thing.
Note: F9 starts with the brightness less than 100% due to a kernel/hal/userspace bug.
So my personal 400ft conclusions:
- We should dim on idle by default, and turn this option on even when on AC power
- We should make suspend and resume faster so we can automatically sleep and resume when idle.
I’ve also been playing with other powersaving techniques like knobbling dirty writeback, noatime, ALPM, changing the screen refresh rate and also powering down cores on a CPU. I’ll blog about these later.
If you are interested in this sort of stuff, I’m presenting at the Red Hat summit next week in Boston with a paper titled “Laptop power management”.