[ltp] battery life on X60 Kubuntu vs XP

[Igor V. Rafienko]

on May 18, 2007, 19:01, Uwe Brauer wrote:

[ ... ]

> I just bought the extended battery for the X60s, however the Kubuntu 
> energy monitor tells me I have 4 hours with full battery while in XP I 
> have 5 hours. I have not checked so far, but could it be that the energy 
> saving method is much better in XP than in Kubuntu?


It's close to impossible to tell what the reason for this may be, since 
you have not told anything that may help narrowing down the topic:

* Are you measuring XP and Kubuntu with roughly the same workload? (e.g.
   idle with no powerhungry services running)
* Regardless of what XP and Kubuntu are telling you, what is the *exact*
   power draw given that same workload? (on linux, tp-smapi is your friend.
   Check the stats in /sys/devices/platform/smapi/BAT0/power_now

Now, assuming that it *is* actually the case that the power drain in 
Kubuntu is 20% higher:

* Is the CPU in the lowest possible C-state on battery? (C4, I believe).
* Are you using the powersave governor when on battery?
* Do you have wifi on? If so, are you using power saving features for the
   wireless card?
* Is USB (uhci_hcd primarily) preventing the cpu from reaching C4?
* Have you tried powertop (<URL: http://linuxpowertop.org/>> to flesh out
   the prospective culprit?
* Which frequency is the cpu running on? Is the second core active? (not
   sure that the latter makes a difference, though)





ivr
-- 
VB, by comparison, treats you like a secretary pecking on MS Office.
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