[ltp] Re: Is 21W good or too much for a dual core duo thinkpad?

[Daniel Pittman]

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Marius Gedminas <mgedmin@b4net.lt> writes:
> On Tue, Oct 16, 2007 at 12:11:06AM -0700, Marc MERLIN wrote:
>
>> So now, I have to ask: is 21W expected for a T7200 CPU (dual core duo
>> 2Ghz) throttled down to 1Ghz 95%+ of the time (according to
>> powertop)?
>
> My T61 has a two-core T7100 (core 2 duo 1.8 GHz).  Normal daily use
> requires about 18W (2.5 hours of battery).  I got it down to a bit
> over 10W by following all powertop's suggestions, killing powernowd
> (and setting the cpu governor to ondemand), setting backlight to 10%
> with xbacklight, unplugging all USB devices (including built-in
> bluetooth) and replacing compiz with metacity.  Killing wifi didn't
> appear to have any effect to power usage.  Setting LCD backlight to
> 50% upped the power usage to 13.6W but made the laptop usable.
>
> My gut feeling for your 21W is "blame ATI" (my laptop has Intel GM965
> video).

The Intel video hardware seems to make a huge difference in power load.

The one question I have, since I don't yet have a dual-core machine, is
what difference it makes to disable one of the two CPU cores when you
are not needing the CPU power?

Rumor, in the form of comments from kernel developers in CPU hotplug
threads, has it that this can deliver a notable power saving.=20=20

Since I don't have a dual core CPU I have not even checked if this is
possible and since I am lazy I wonder if anyone else already knows?

Regards,
        Daniel
=2D-=20
Daniel Pittman <daniel@cybersource.com.au>           Phone: 03 9621 2377
Level 4, 10 Queen St, Melbourne             Web: http://www.cyber.com.au
Cybersource: Australia's Leading Linux and Open Source Solutions Company

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