From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chirag Jog Subject: Re: Fwd: -rt and PowerPC Date: Mon, 31 Dec 2007 09:56:23 +0530 Message-ID: <20071231042623.GA8421@linux.vnet.ibm.com> References: <200712241140.00738.sripathik@in.ibm.com> <562556514-1198501255-cardhu_decombobulator_blackberry.rim.net-1487612076-@bxe137.bisx.prod.on.blackberry> <20071226042325.GA23220@hells-kitchen.in.ibm.com> <1198859012.12074.0.camel@sven.thebigcorporation.com> Reply-To: Chirag Jog Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Cc: Sripathi Kodi , linux-rt-users@vger.kernel.org To: Sven-Thorsten Dietrich Return-path: Received: from E23SMTP06.au.ibm.com ([202.81.18.175]:36931 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752437AbXLaE2I (ORCPT ); Sun, 30 Dec 2007 23:28:08 -0500 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.18.234]) by e23smtp06.au.ibm.com (8.13.1/8.13.1) with ESMTP id lBV4S0RW006777 for ; Mon, 31 Dec 2007 15:28:00 +1100 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id lBV4QpKd2678918 for ; Mon, 31 Dec 2007 15:26:51 +1100 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id lBV4QYai019727 for ; Mon, 31 Dec 2007 15:26:35 +1100 Content-Disposition: inline In-Reply-To: <1198859012.12074.0.camel@sven.thebigcorporation.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: Hi, * Sven-Thorsten Dietrich [2007-12-28 08:23:32]: > On Wed, 2007-12-26 at 09:53 +0530, Chirag Jog wrote: > > * sven@thebigcorporation.com [2007-12-24 13:00:30]: > > > > Hi, > > Sorry for top-posting the last email. Have not learned how to inline on > the Blackberry. > > Comments below. > > > > Do you have DEBUG and LOCKDEP configured? > > CONFIG_PREEMPT_DEBUG is enabled > > but LOCKDEP is not. > > > > > > -----Original Message----- > > > From: Sripathi Kodi > > > > > > We are trying to get a ppc64 box booted with the -rt kernel. > > > > > > Tried the latest 2.6.24-rc5-rt1 kernel. > > > > > > Everything goes well [ kernel boots up etc] until the services > > > start coming up. > > > It takes a lot of time at Starting udev. > > > After which either services take too long to start or we get > > > SEGFAULT. > > I have seen this exact behavior with lockdep enabled on earlier x86-SMP > Kernels. I saw the issue predominantly on larger SMP machines, but it > behaved much like a race. This was observed on 2.6.21 Kernels, I will > try and verify whether .23 has the same behavior. > > We eventually bisected it down to CONFIG_PROVE_LOCKING, but I wasn't > totally convinced whethere the root cause was in lockdep, or > elsewhere. > > > > > > > This is easily reproducible. Also if we get a chance to login; > > > simple commands like ls, vi etc take either too long or get > > > SEGFAULT. > > > > > > > Booting the kernel with maxcpus=1 or turning off SMP, doesn't > > > solve the problem. > > > > > Hmmm, so have you COMPILED-out SMP, or just booted with nosmp? > > It might help narrowing this down to compile a UP Kernel. We have tried both options, compiled out SMP and boot with maxcpus=1. Similar results. Sripathi also tried with turning off HIGH_RES_TIMERS but didn't seem to help. The system took forever to come up. > > Thanks > > Sven -- Cheers, Chirag Jog