Reading battery consumes a lot of CPU

Reading battery consumes a lot of CPU

[Jan Rychter]

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I've reported this a number of times (using various hardware, in fact)
over the last year or so. Thought I'd resend.

Reading the battery status seems to consume a disproportionate amount of
CPU time, such that running battery applets (wmacpi, etc) becomes
impractical. If I use them in their normal mode, the CPU rarely slows
down for me using cpudynd.

To give you an example, my wmacpi that updates the information every 30
seconds (!) has consumed 8 minutes and 10 seconds of CPU time over the
last 12 or so hours of laptop use.

jwr       6826  2.6  0.1  2668  436 ?        S    05:58   8:10 wmacpi

This makes it impractical to run battery monitors.

I'm using Linux-2.4.25 on a Sharp Mebius PC-MT2-H1 (and previously over
the last year all kinds of kernels and patches on this laptop and on a
Sharp Mebius PC-MT1-H5).

--J.

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Re: Reading battery consumes a lot of CPU

[Pavel Machek]

Hi!

> I've reported this a number of times (using various hardware, in fact)
> over the last year or so. Thought I'd resend.

Reading battery status is inherently slow, because battery hw is
connected over slow bus (i2c) and driven from acpi without
interrupts.

								Pavel
-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]


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