Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753626AbYATLTk (ORCPT ); Sun, 20 Jan 2008 06:19:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752714AbYATLTb (ORCPT ); Sun, 20 Jan 2008 06:19:31 -0500 Received: from hoefnix.telenet-ops.be ([195.130.132.54]:52250 "EHLO hoefnix.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752149AbYATLTa (ORCPT ); Sun, 20 Jan 2008 06:19:30 -0500 Date: Sun, 20 Jan 2008 12:18:40 +0100 (CET) From: Geert Uytterhoeven To: Andi Kleen Cc: Matt Mackall , Chodorenko Michail , linux-kernel@vger.kernel.org Subject: Re: PROBLEM: Celeron Core In-Reply-To: <20080119042750.GA24481@one.firstfloor.org> Message-ID: References: <3ed23423adebae08e8f75b6a6a7ce7ff@one.by> <1200702477.25782.41.camel@cinder.waste.org> <20080119011506.GA23798@one.firstfloor.org> <1200715842.25782.95.camel@cinder.waste.org> <20080119042750.GA24481@one.firstfloor.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1309 Lines: 32 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@linux-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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/