Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269369AbUIIINh (ORCPT ); Thu, 9 Sep 2004 04:13:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269370AbUIIINh (ORCPT ); Thu, 9 Sep 2004 04:13:37 -0400 Received: from gateway-1237.mvista.com ([12.44.186.158]:52476 "EHLO av.mvista.com") by vger.kernel.org with ESMTP id S269369AbUIIINW (ORCPT ); Thu, 9 Sep 2004 04:13:22 -0400 Message-ID: <41400FAD.4050802@mvista.com> Date: Thu, 09 Sep 2004 01:09:17 -0700 From: George Anzinger Reply-To: george@mvista.com Organization: MontaVista Software User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20030225 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jesse Barnes CC: john stultz , Christoph Lameter , Albert Cahalan , lkml , tim@physik3.uni-rostock.de, Ulrich.Windl@rz.uni-regensburg.de, Len Brown , linux@dominikbrodowski.de, 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) References: <1094159238.14662.318.camel@cog.beaverton.ibm.com> <1094700768.29408.124.camel@cog.beaverton.ibm.com> <413FDC9F.1030409@mvista.com> <200409082337.30961.jbarnes@engr.sgi.com> In-Reply-To: <200409082337.30961.jbarnes@engr.sgi.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1147 Lines: 27 Jesse Barnes wrote: > On Wednesday, September 8, 2004 9:31 pm, George Anzinger wrote: > >>a.) resolution. If you don't put a limit on this you will invite timer >>storms. Currently, by useing 1/HZ resolution, all timer "line up" on ticks >>and reduce the interrupt overhead that would occure if we actually tried to >>give "exactly" what was asked for. This is a matter of math and can be >>handled (assuming we resist the urge to go shopping :)) > > > This can be bad though if lots of CPUs hit it at the same time or nearly so if > they're all trying to write the same cacheline or two. I think that most of the SMP issues your talking about have gone away with 2.6 where we have seperate timer lists for each cpu. -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml - 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/