Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262071AbUIOIzi (ORCPT ); Wed, 15 Sep 2004 04:55:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263540AbUIOIzi (ORCPT ); Wed, 15 Sep 2004 04:55:38 -0400 Received: from natnoddy.rzone.de ([81.169.145.166]:59788 "EHLO natnoddy.rzone.de") by vger.kernel.org with ESMTP id S262071AbUIOIzh (ORCPT ); Wed, 15 Sep 2004 04:55:37 -0400 Date: Wed, 15 Sep 2004 10:54:50 +0200 From: Dominik Brodowski To: George Anzinger Cc: Christoph Lameter , john stultz , Albert Cahalan , lkml , tim@physik3.uni-rostock.de, Ulrich.Windl@rz.uni-regensburg.de, Len Brown , David Mosberger , Andi Kleen , paulus@samba.org, schwidefsky@de.ibm.com, jimix@us.ibm.com, keith maanthey , greg kh , Patricia Gaughen , Chris McDermott Subject: Re: [RFC][PATCH] new timeofday core subsystem (v.A0) Message-ID: <20040915085450.GA5242@dominikbrodowski.de> Mail-Followup-To: Dominik Brodowski , George Anzinger , Christoph Lameter , john stultz , Albert Cahalan , lkml , tim@physik3.uni-rostock.de, Ulrich.Windl@rz.uni-regensburg.de, Len Brown , David Mosberger , Andi Kleen , paulus@samba.org, schwidefsky@de.ibm.com, jimix@us.ibm.com, keith maanthey , greg kh , Patricia Gaughen , Chris McDermott References: <1094700768.29408.124.camel@cog.beaverton.ibm.com> <413FDC9F.1030409@mvista.com> <1094756870.29408.157.camel@cog.beaverton.ibm.com> <4140C1ED.4040505@mvista.com> <1095114307.29408.285.camel@cog.beaverton.ibm.com> <41479369.6020506@mvista.com> <4147F774.6000800@mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4147F774.6000800@mvista.com> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1047 Lines: 22 On Wed, Sep 15, 2004 at 01:04:04AM -0700, George Anzinger wrote: > >One could do this but we want to have a tickless system. The tick is only > >necessary if the time needs to be adjusted. > > I really think a tickless system, for other than UML systems, is a loosing > thing. The accounting overhead on context switch (which increases as the > number of switchs per second) will cause more overhead than a periodic > accounting tick once a respectable load appears. ^^^^^^^^^^^^^^^^ On a largely idle system (like notebooks on battery power in typical use) the accounting overhead will be less a problem. However, the CPU being woken up each millisecond will cause an increased battery usage. So if the load is less than a certain threshold, tickless systems do make much sense. Dominik - 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/