powerd doesn't decrease CPU frequency in some cases
rpaulo at fnop.net
Mon Dec 24 15:46:23 PST 2007
At Mon, 24 Dec 2007 23:16:54 +0200,
Aragon Gouveia wrote:
> | By Rui Paulo <rpaulo at fnop.net>
> | [ 2007-12-24 14:43 +0200 ]
> > Isn't it better to teach est(4) to ignore values that differ in, say,
> > +/- 5Mhz ?
> I agree my patch isn't ideal. I was thinking about it today and it might
> be useful to implement something that ignores frequencies whose power
> ratings don't differ by more than X mW. In my case, both 2201 and 2200 are
> rated to draw 35000 mW. The question is, in these cases which one of the
> two should be ignored? Can't ignore both...
I think you can ignore one of them, which one doesn't really matter
because the power levels are the same. I suspect that, in these cases,
the 2001 comes after 2000 in the EST table, so if we ignore a value
already present, 2000 will remain and 2001 will be ignored.
> Sorry Andrey, I missed your patch. Was a bit overly excited when I saw
> someone else finally experiencing the same problem as me after receiving
> zero response a month ago when I posted about it. :)
> Something I asked in my post a month ago was where does
> dev.cpu.X.freq_levels get its data? I was thinking it might be something
> that can be addressed with a patched ACPI DSDT?
dev.cpu.0.freq_levels is the combiation of several power/speed
throttling sources, namely, est(4), acpi_throttle(4), etc. The API
that deals with this is cpufreq(8).
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