From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261623AbVGKN03 (ORCPT ); Mon, 11 Jul 2005 09:26:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261609AbVGKN02 (ORCPT ); Mon, 11 Jul 2005 09:26:28 -0400 Received: from clock-tower.bc.nu ([81.2.110.250]:29901 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S261623AbVGKN01 (ORCPT ); Mon, 11 Jul 2005 09:26:27 -0400 Subject: Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt From: Alan Cox To: Lee Revell Cc: Andrew Morton , arjan@infradead.org, azarah@nosferatu.za.org, cw@f00f.org, Linux Kernel Mailing List , torvalds@osdl.org, christoph@lameter.org In-Reply-To: <1120936561.6488.84.camel@mindpipe> References: <200506231828.j5NISlCe020350@hera.kernel.org> <20050708214908.GA31225@taniwha.stupidest.org> <20050708145953.0b2d8030.akpm@osdl.org> <1120928891.17184.10.camel@lycan.lan> <1120932991.6488.64.camel@mindpipe> <1120933916.3176.57.camel@laptopd505.fenrus.org> <1120934163.6488.72.camel@mindpipe> <20050709121212.7539a048.akpm@osdl.org> <1120936561.6488.84.camel@mindpipe> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1121088186.7407.61.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Mon, 11 Jul 2005 14:23:08 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > Because some machines exhibit appreciable latency in entering low power > > state via ACPI, and 1000Hz reduces their battery life. By about half, > > iirc. > > > Then the owners of such machines can use HZ=250 and leave the default > alone. Why should everyone have to bear the cost? They need 100 really it seems, 250-500 have no real effect and on the Dell I tried 250 didn't stop the wild clock slew from the APM bios either. I played with this a fair bit on a couple of laptops. I've not seen anything > 20% saving however so I've no idea who/why someone saw 50%