linux-kernel - Re: PROBLEM: Celeron Core

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Message-ID: <Pine.LNX.4.64.0801201216520.28200@anakin>
Date:	Sun, 20 Jan 2008 12:18:40 +0100 (CET)
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	Matt Mackall <mpm@...enic.com>, Chodorenko Michail <misha@....by>,
	linux-kernel@...r.kernel.org
Subject: Re: PROBLEM: Celeron Core

On Sat, 19 Jan 2008, Andi Kleen wrote:
> > So while throttling may be less efficient in terms of watt seconds used
> > to compile something than running at full speed, it is incorrect to say
> > it uses less power. One machine running for an hour throttled to 50%
> > uses less power (and therefore less battery and cooling) than another
> > running at full speed for that same hour.
> 
> Not for the same unit of work. If you just run endless loops you 
> might be true, but most systems don't do that. 

So you mean energy (measured in J).
Power is energy/time unit (measured in W, i.e. J/s).

So I guess what you really want to say is: throttling decreases power
consumption, but on modern CPUs it increases the amount of energy needed
to perform the task.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds
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