From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763095AbXGFVtT (ORCPT ); Fri, 6 Jul 2007 17:49:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760450AbXGFVtJ (ORCPT ); Fri, 6 Jul 2007 17:49:09 -0400 Received: from smtp3.Stanford.EDU ([171.67.20.26]:56100 "EHLO smtp3.stanford.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757996AbXGFVtI (ORCPT ); Fri, 6 Jul 2007 17:49:08 -0400 Subject: Re: v2.6.21.5-rt19 From: Fernando Lopez-Lezcano To: Rui Nuno Capela Cc: Thomas Gleixner , LKML , RT-Users , Ingo Molnar , Steven Rostedt , "jcaceres@ccrma.Stanford.EDU" , Carsten Emde In-Reply-To: <9609.194.65.103.1.1183731007.squirrel@www.rncbc.org> References: <1183582155.3291.160.camel@chaos> <9609.194.65.103.1.1183731007.squirrel@www.rncbc.org> Content-Type: text/plain Date: Fri, 06 Jul 2007 14:49:04 -0700 Message-Id: <1183758545.20747.34.camel@cmn3.stanford.edu> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-4.fc4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2007-07-06 at 15:10 +0100, Rui Nuno Capela wrote: > Hi, > > On Wed, July 4, 2007 21:49, Thomas Gleixner wrote: > > I'm pleased to announce the v2.6.21.5-rt19 kernel on behalf of Ingo. > > > > > > It can be downloaded from the usual place: > > > > http://people.redhat.com/mingo/realtime-preempt/ > > > > More info about the -rt patch set can be found in the RT wiki: > > > > http://rt.wiki.kernel.org > > > > Changes since 2.6.21.5-rt18: > > > > - Fixed a nasty and hard to track down slowness / boot problem on SMP > > machines with CONFIG_NOHZ enabled. The problem was caused by the timer > > wheel base lock held during the get_next_timer_interrupt() call in the > > idle path, which eventually led to a bogus PI boosting of the idle task > > and in consequence a stale wrong scheduler selection for the affected idle > > task. > > > > Kudos to Carsten Emde, who patiently and meticulously isolated the > > problem and provided the traces, which allowed to identify the root cause. > > > > Problem solution: Prevent idle task boosting > > > > - back port of the ntp / clock_was_set fix > > > > - integration of the processor_idle fix from Venki Pallipadi, which > > resolves boot issues on some platforms > > > > - ep93xx clock events fix from Manfred Gruber > > > > Maybe someone remember me whining about troubles with 2.6.21-rt2..18 on my > Core2 T7200 laptop (fujitsu-siemens amilo i1520). > > Althought I'm still with my fingers crossed, I can tell the good news are > that 2.6.21.5-rt19 (and -rt20) does behave far better now on the very same > box. Yes, it works much better indeed... Ingo: is there a place where I can read about the changes in different rtxx releases? What is new/better/fixed in rt20? (I see scheduler stuff in a diff from rt19 to rt20 but I don't really know what it means). -- Fernando > I've more than 8 hours up and running now, without a single glimpse of the > bad symptoms, which used to show in a matter of minutes if not earlier > during init time. > > Congratulations. I'm not sure whether this problem can be closed for good, > though, just because you mention the slowness fix applies to CONFIG_NOHZ=Y > and I'm quite sure my badness surged either way. > > But at least -rt is usable again here and that just makes me happier :) > > Cheers.