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Re: Battery use. was Re: Scary IDE message and a hang in fresh Etch installation

On Wed, Jan 03, 2007 at 04:54:05PM +0000, Ken Moffat wrote:
>  I think I'm seeing a reduced sleep time with on an ibook
> G4 (7447A cpu).  At first I assumed the battery was showing it's
> age, but I've just run some tests and I think there _is_ heavier
> battery usage.
>  My test was somewhat simplistic (charge while sleeping, open,
> record battery information, sleep for approx 6 hours, open, record,
> calculate).  It's important to sleep for a similar time on each test,
> from a full charge, because the battery use reported is not linear.
>  With (compiled with gcc-4.1.1) I saw the charge decline by
> 240 units (mA?) in 21551 seconds, or an average time-per-unit of
> 89.8 seconds.  With (compiled with gcc-4.0.2, running on a
> different partition) I saw a decline of only 193 units in 21532
> seconds (111.5 seconds per unit).
 I now think that in something did not sleep as deeply as in
earlier, or later, kernels.  Current kernels seem to sleep well, so I
guess the occasional "thirsty" one isn't too bad.  The data I
accumulated follow (one run per kernel, apart from when I mistimed
the sleep, but most seem consistent):

kernel		gcc	units	seconds	secs/unit	4.0.2	193	21532	111.565	4.1.1	240	21551	 89.7958	4.0.2	189	21621	114.397	4.1.1	130	14441	111.085
 and after more sleep	216	21506	 99.5648	4.1.1	198	22348	112.869	4.1.1	190	21663	114.016
2.6.20-rc4	4.1.1	192	21715	113.099

 I guess, based on when I woke it up too soon, and then put it to
sleep for the remaining time, that the wake up and restarting X uses
a significant amount of power.

das eine Mal als Tragödie, das andere Mal als Farce

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