From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750961AbVHQHxt (ORCPT ); Wed, 17 Aug 2005 03:53:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750959AbVHQHxt (ORCPT ); Wed, 17 Aug 2005 03:53:49 -0400 Received: from ylpvm15-ext.prodigy.net ([207.115.57.46]:7567 "EHLO ylpvm15.prodigy.net") by vger.kernel.org with ESMTP id S1750759AbVHQHxs (ORCPT ); Wed, 17 Aug 2005 03:53:48 -0400 X-ORBL: [67.117.73.34] Date: Wed, 17 Aug 2005 00:53:21 -0700 From: Tony Lindgren To: Con Kolivas Cc: vatsa@in.ibm.com, tuukka.tikkanen@elektrobit.com, akpm@osdl.org, johnstul@us.ibm.com, linux-kernel@vger.kernel.org, ak@muc.de, george@mvista.com Subject: Re: [ck] [PATCH] dynamic-tick patch modified for SMP Message-ID: <20050817075320.GC16992@atomide.com> References: <20050812201946.GA5327@in.ibm.com> <200508160230.52860.kernel@kolivas.org> <20050816131942.GD8608@in.ibm.com> <200508162323.33333.kernel@kolivas.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200508162323.33333.kernel@kolivas.org> User-Agent: Mutt/1.5.6+20040907i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Con Kolivas [050816 06:23]: > 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. Sounds good! I only got the APIC stuff working properly on P3, but not on P4. Tony