From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965213AbVHPNYz (ORCPT ); Tue, 16 Aug 2005 09:24:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965212AbVHPNYz (ORCPT ); Tue, 16 Aug 2005 09:24:55 -0400 Received: from mail15.syd.optusnet.com.au ([211.29.132.196]:58768 "EHLO mail15.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S965213AbVHPNYz (ORCPT ); Tue, 16 Aug 2005 09:24:55 -0400 From: Con Kolivas To: vatsa@in.ibm.com Subject: Re: [ck] [PATCH] dynamic-tick patch modified for SMP Date: Tue, 16 Aug 2005 23:23:32 +1000 User-Agent: KMail/1.8.2 Cc: tony@atomide.com, tuukka.tikkanen@elektrobit.com, akpm@osdl.org, johnstul@us.ibm.com, linux-kernel@vger.kernel.org, ak@muc.de, george@mvista.com References: <20050812201946.GA5327@in.ibm.com> <200508160230.52860.kernel@kolivas.org> <20050816131942.GD8608@in.ibm.com> In-Reply-To: <20050816131942.GD8608@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508162323.33333.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 16 Aug 2005 23:19, Srivatsa Vaddagiri wrote: > On Tue, Aug 16, 2005 at 02:30:51AM +1000, Con Kolivas wrote: > > Time definitely was lost the longer the machine was running. > > I think I found the reason for time drift. Basically cur_timer->mark_offset > doesnt expect to be called from non-timer interrupt handler. Hence it drops > one jiffy from the lost count. I fixed this in some "crude" fashion and > time has not drifted so far or is pretty much close to what it was in > pre-smp version. Will find a neat way to fix this and post a patch soon. > > > You mean disable it at runtime or not compile it in at all? Disabling it > > at runtime caused what I described to you as PIT mode (long stalls etc). > > I think I have recreated this on a machine here. Disabling > CONFIG_DYN_TICK_APIC at compile-time didnt seem to make any difference. > Will look at this problem next. Excellent. Mind you the APIC dyntick never really worked well on the pre-smp version on any hardware I tried it on so if you get both the APIC and PIT version working well you're doing great. Thanks! Con