From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262310AbVHCPVz (ORCPT ); Wed, 3 Aug 2005 11:21:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262314AbVHCPVy (ORCPT ); Wed, 3 Aug 2005 11:21:54 -0400 Received: from ms-smtp-02-smtplb.ohiordc.rr.com ([65.24.5.136]:60358 "EHLO ms-smtp-02-eri0.ohiordc.rr.com") by vger.kernel.org with ESMTP id S262310AbVHCPUg (ORCPT ); Wed, 3 Aug 2005 11:20:36 -0400 Date: Wed, 03 Aug 2005 11:20:29 -0400 From: ambx1@neo.rr.com Subject: Re: Power consumption HZ100, HZ250, HZ1000: new numbers To: "Theodore Ts'o" Cc: James Bruce , David Weinehall , Lee Revell , Pavel Machek , Marc Ballarin , linux-kernel@vger.kernel.org Message-id: MIME-version: 1.0 X-Mailer: iPlanet Messenger Express 5.2 HotFix 2.04 (built Feb 8 2005) Content-type: text/plain; charset=us-ascii Content-language: en Content-transfer-encoding: 7BIT Content-disposition: inline X-Accept-Language: en Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- From: Theodore Ts'o Date: Monday, August 1, 2005 4:42 pm Subject: Re: Power consumption HZ100, HZ250, HZ1000: new numbers > 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 > throw in > > Con's disturbing AV benchmark results (1). As a result, some of > us > > don't think 250HZ is a great tradeoff to make > _for_the_default_value_. > 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. > > - Ted Also, my understanding was that when we properly support usb suspend, this won't be an issue anyway for much usb hardware. I think it's possible to put some mice to sleep when there isn't any motion and then wakeup later. 4.4% savings may not be much, but these things do add up. For a laptop's workload, I think this is worth it. Thanks, Adam