From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030319AbXDZJyD (ORCPT ); Thu, 26 Apr 2007 05:54:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030323AbXDZJyB (ORCPT ); Thu, 26 Apr 2007 05:54:01 -0400 Received: from amsfep17-int.chello.nl ([62.179.120.12]:23635 "EHLO amsfep17-int.chello.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030319AbXDZJyB (ORCPT ); Thu, 26 Apr 2007 05:54:01 -0400 Subject: Re: recomended way to check longest period that interupts are disabled ? From: Peter Zijlstra To: Mike Mattie Cc: lkml In-Reply-To: <20070426021350.29ddfa0a@reforged> References: <20070426021350.29ddfa0a@reforged> Content-Type: text/plain Date: Thu, 26 Apr 2007 11:53:57 +0200 Message-Id: <1177581237.26937.105.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2007-04-26 at 02:13 -0700, Mike Mattie wrote: > Hello, > > I am still struggling to track down problems with audio playback. I get intermittent: > > Apr 26 02:01:40 reforged [13230.947879] cannot submit sync urb (err = -45) > > I have tackled the scheduler issues to where I really don't think the > driver is being starved at all. I am running audacious like so: > > schedtool -R -p 50 -n 1 -e audacious > > At this point the strongest correlation I can get is that starting > programs seems to trigger the stutter. I have suspected IO for > some time. > > My system image , / & /usr are on a libata (VIA PATA) driver. > I have disabled the write-cache , but I also have noatime set > on mount, for /usr > > My big suspicion is that one of my drivers, likely IO is > disabling interrupts for too long. > > I have looked but not found a tool for measuring the longest > period interrupts are disabled and pointing the finger at > the culprit, could anyone on this list recommend tools that > might help me pinpoint what is going on ? > > I would also be delighted for any sort of recommended latency > testing tools. > > pin-pointing this is going to be a "learning experience" but > every time I think I am about to have a bonding moment with > the kernel audio skips; I am highly motivated. The -rt kernel contains a full latency tracer. http://people.redhat.com/mingo/realtime-preempt/ Some hardware just isn't up to the job though...