From owner-cvs-all Tue Jan 14 17:18:10 2003 Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 84F5B37B405; Tue, 14 Jan 2003 17:18:08 -0800 (PST) Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id BC15643EB2; Tue, 14 Jan 2003 17:18:07 -0800 (PST) (envelope-from gallatin@cs.duke.edu) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.12.6/8.12.6) with ESMTP id h0F1I1ro003056 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Tue, 14 Jan 2003 20:18:01 -0500 (EST) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.11.6/8.9.1) id h0F1Huw74699; Tue, 14 Jan 2003 20:17:56 -0500 (EST) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15908.46788.141735.858350@grasshopper.cs.duke.edu> Date: Tue, 14 Jan 2003 20:17:56 -0500 (EST) To: Peter Wemm Cc: John Baldwin , Wilko Bulte , cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org, Nate Lawson Subject: Re: cvs commit: src/sys/dev/acpica acpi_cpu.c In-Reply-To: <20030114230057.81B422A89E@canning.wemm.org> References: <20030114173224.A74488@grasshopper.cs.duke.edu> <20030114230057.81B422A89E@canning.wemm.org> X-Mailer: VM 6.75 under 21.1 (patch 12) "Channel Islands" XEmacs Lucid Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Peter Wemm writes: > Andrew Gallatin wrote: > > John Baldwin [jhb@FreeBSD.org] wrote: > > > aggressive policies in the future. You could change the speed on > > > your desktop by changing the performance speed to be 6 (75%) using > > > the sysctl for example: > > > > The scary thing is that for my destop setup, I can turn my speed down > > to 25% on my P4 and not really feel a difference in xterms, editors > > and soforth. (I CAN see a difference, I just don't mind it much). > > > > Any idea about how much power this actually saves on a desktop? > > FWIW, we see a (measured) difference of about 50W on 2.2GHz P4's simply by > turning machdep.cpu_idle_hlt on and off. I expect the clock throttling > would make similar differences. For 1U rack-mount systems (especially in > California) this is a Big Deal. Yes, it is. 2 years ago, just as I was leaving Duke and the Enrons of the world were raping California consumers, some people in my research group were looking at doing energy-aware server load balancing. Eg, you suspend a server to save power if load is low, and at peak times you bring additional servers on line. We were using PIIIs and APM, waking with wake-on-lan. I bet everything we did would translate to P4's and ACPI... See http://www.cs.duke.edu/ari/publications/balance-of-power.ps (That's more of a pie-in-the-sky thing.. I don't know where the paper with the hard numbers went). Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message