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    SubjectRe: [linux-pm] Power Management framework proposal
    Hi!

    > > let me give you a real world example then, and the numbers I'm using are
    > > ballpark the same as you'll find in a (mobile) core 2 duo datasheet, I
    > > just rounded them a little so that the math works out nice.
    > >
    > > power at full speed: 34W
    > > power at half speed: 24W
    > > power at idle: 1W
    >
    > I have usually seen different numbers, for example:
    >
    > http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/30430.pdf

    Trust Arjan, modern cpus work as he describes.

    > Although this paper speaks about thermal design power instead of power
    > consumption, i suppose that it should be roughly equal.
    >
    > For example Athlon 64 3700 (ADA3700AEP5AR):
    >
    > 2.4 GHz, 1.5 V -> 89 W
    > 2.2 GHz, 1.4 V -> 72 W
    > 2.0 GHz, 1.3 V -> 53 W
    > 1.8 GHz, 1.2 V -> 39 W
    > 1.0 GHz, 1.1 V -> 22 W

    I guess that means athlon 64 is 'old'.

    > Even my measurement on PC (Athlon X2, VIA K8T890) of complete PC power
    > consumption shows that it is more efficient to be busy for 2 time units
    > on 1 GHz than be busy for 1 time unit and be idle for 1 time unit
    > on 2 GHz.
    >
    > 1 GHz:
    > both cores idle: 48 W
    > one core busy: 57 W
    > two cores busy: 66 W

    2 sec decoding video at both cores: 132J

    > 2 GHz:
    > both cores idle: 54 W
    > one core busy: 78 W
    > two cores busy: 95 W

    1 sec decode @ 2GHz + 1 sec idle @ 1GHz: 143J

    So even on your hw difference is not too big... and take a look at
    numbers from core2duo.

    Actually...

    4 sec decode @ 1 core @ 1GHz: 57*4=228J
    1 sec decode @ 2 cores @ 2GHz, then idle: 95 + 48*3 = 142+95 = 235J...

    Ok, so it is still win, but even smaller one..
    Pavel
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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