From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261183AbVHBEu6 (ORCPT ); Tue, 2 Aug 2005 00:50:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261365AbVHBEu6 (ORCPT ); Tue, 2 Aug 2005 00:50:58 -0400 Received: from CYRUS.andrew.cmu.edu ([128.2.10.175]:39346 "EHLO mail-fe5.andrew.cmu.edu") by vger.kernel.org with ESMTP id S261183AbVHBEu4 (ORCPT ); Tue, 2 Aug 2005 00:50:56 -0400 Message-ID: <42EEFB9B.10508@andrew.cmu.edu> Date: Tue, 02 Aug 2005 00:50:35 -0400 From: James Bruce User-Agent: Debian Thunderbird 1.0.2 (X11/20050602) X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Theodore Ts'o" CC: David Weinehall , Lee Revell , Pavel Machek , Marc Ballarin , linux-kernel@vger.kernel.org Subject: Re: Power consumption HZ100, HZ250, HZ1000: new numbers References: <20050730195116.GB9188@elf.ucw.cz> <1122753864.14769.18.camel@mindpipe> <20050730201049.GE2093@elf.ucw.cz> <42ED32D3.9070208@andrew.cmu.edu> <20050731211020.GB27433@elf.ucw.cz> <42ED4CCF.6020803@andrew.cmu.edu> <20050731224752.GC27580@elf.ucw.cz> <1122852234.13000.27.camel@mindpipe> <20050801074447.GJ9841@khan.acc.umu.se> <42EE4B4A.80602@andrew.cmu.edu> <20050801204245.GC17258@thunk.org> In-Reply-To: <20050801204245.GC17258@thunk.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Theodore Ts'o wrote: > On Mon, Aug 01, 2005 at 12:18:18PM -0400, James Bruce wrote: >>The tradeoff is a realistic 4.4% power savings vs a 300% increase in >>the minimum sleep period. A user will see zero power savings if they >>have a USB mouse (probably 99% of desktops). On top of that, we can ^^^^^^^^ > Most laptops (including mine, a Thinkpad T40) use a PS/2 mouse. So in > the places where power consumption savins matters most, it's usually > quite possible to function without needing any USB devices. The 90% > figure isn't at all right; in fact, it may be that over 90% of the > laptops still use PS/2 mice and keyboards. Yes, laptops are mostly PS/2, which is why I only claimed a statistic for desktops. Desktops pretty much all use USB mice now. If 250Hz were only being sold as an option for laptops, we could leave it at that, yet its being pushed as a default that's "good for everyone". For desktops this is not currently true at all. By the time USB is fixed to do power saving, we'll probably have a working tick-skipping patch which makes the whole HZ argument moot. - Jim Bruce