EST (Enhanced Intel SpeedStep(R) Technology) on amd64

Alexander Motin mav at
Fri Jan 9 15:55:27 PST 2009

Gabriel Lavoie wrote:
> Another question. Any reason why powerd doesn't use
> dev.est.0.freq_settings when it is available instead of
> dev.cpu.0.freq_levels?
> On my system:
> dev.cpu.0.freq_levels: 2500/88000 2187/77000 2000/47608 1750/41657
> 1600/44616 1400/39039 1200/41800 1050/36575 900/31350 750/26125
> 600/20900 450/15675 300/10450 150/5225
> dev.est.0.freq_settings: 2500/88000 2000/47608 1600/44616 1200/41800

dev.cpu.0.freq_levels is just a mix of est and p4tcc levels. By default 
powerd uses all of them. If you really wish, you can disable p4tcc with:
then dev.cpu.0.freq_levels will be equal to dev.est.0.freq_settings.

> If I don't lower the polling time of powerd to 100ms, my system
> becomes way too much unresponsive because powerd takes too much time
> to increase the frequency, step by step and there are a lot of
> settings with dev.est.0.freq_settings (14). With
> dev.est.0.freq_settings, the minimal setting is high enough so the
> system stays responsive and powerd would bring it up to max frequency
> quickly enough, even if the polling time is still kept at 500ms. This
> would work more like Windows or Linux where the lowest frequency at
> which the CPU will drop is the lowest EIST gives (here 1200 MHz).

I have just merged updated powerd to 7-STABLE to address this issue.

Alexander Motin

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