Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261220AbUJ3Rte (ORCPT ); Sat, 30 Oct 2004 13:49:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261224AbUJ3Rte (ORCPT ); Sat, 30 Oct 2004 13:49:34 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:55972 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S261220AbUJ3Rtc (ORCPT ); Sat, 30 Oct 2004 13:49:32 -0400 Subject: Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4] From: Lee Revell To: Ingo Molnar Cc: Florian Schmidt , Paul Davis , Thomas Gleixner , LKML , mark_h_johnson@raytheon.com, Bill Huey , Adam Heath , Michal Schmidt , Fernando Pablo Lopez-Lezcano , Karsten Wiese , jackit-devel , Rui Nuno Capela In-Reply-To: <20041030115808.GA29692@elte.hu> References: <20041029193303.7d3990b4@mango.fruits.de> <20041029172151.GB16276@elte.hu> <20041029172243.GA19630@elte.hu> <20041029203619.37b54cba@mango.fruits.de> <20041029204220.GA6727@elte.hu> <20041029233117.6d29c383@mango.fruits.de> <20041029212545.GA13199@elte.hu> <1099086166.1468.4.camel@krustophenia.net> <20041029214602.GA15605@elte.hu> <1099091566.1461.8.camel@krustophenia.net> <20041030115808.GA29692@elte.hu> Content-Type: text/plain Date: Sat, 30 Oct 2004 13:49:29 -0400 Message-Id: <1099158570.1972.5.camel@krustophenia.net> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1349 Lines: 31 On Sat, 2004-10-30 at 13:58 +0200, Ingo Molnar wrote: > * Lee Revell wrote: > > > Here is the dmesg output. It looks like the problem could be related > > to jackd's printing from the realtime thread. But, this has to be the > > kernel's fault on some level, because with an earlier version I get no > > xruns. > > with the earlier version these spinlocks were simply disabling > preemption, while now they will schedule away on contention. If that tty > lock is held for a long time by a lowprio task then that could delay the > highprio thread. We are starting to see priority inversion problems. > But, the core issue is doing tty printouts - does jackd do that > periodically, or only as a reaction to an already existing latency? > No, this cannot be the whole story, because unless verbose mode is specified, jackd will only prints anything if there is an xrun. So there is something else going on. This _really_ feels like a kernel bug. Are you saying that this could still be a jackd problem, even though T3 works perfectly with the exact same jackd binary? Lee - 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/