From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755598Ab0IRPJq (ORCPT ); Sat, 18 Sep 2010 11:09:46 -0400 Received: from mail.openrapids.net ([64.15.138.104]:57299 "EHLO blackscsi.openrapids.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751014Ab0IRPJp (ORCPT ); Sat, 18 Sep 2010 11:09:45 -0400 Date: Sat, 18 Sep 2010 11:09:43 -0400 From: Mathieu Desnoyers To: Matthias Dahl Cc: Linux Kernel Mailing List , Ingo Molnar , Linus Torvalds Subject: Re: [PATCH] sched: Improve latencies under load by decreasing minimum Message-ID: <20100918150943.GA2562@Krystal> References: <201009162048.50941.ml_kernel@mortal-soul.de> <20100918145301.GA19879@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100918145301.GA19879@Krystal> X-Editor: vi X-Info: http://www.efficios.com X-Operating-System: Linux/2.6.26-2-686 (i686) X-Uptime: 11:09:18 up 238 days, 17:46, 4 users, load average: 0.01, 0.03, 0.04 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Mathieu Desnoyers (mathieu.desnoyers@efficios.com) wrote: > * Matthias Dahl (ml_kernel@mortal-soul.de) wrote: > > Hi. > > > > I don't know if this is relevant but I just tried this ontop 2.6.35.4 while > > investigating a different problem and it was quite easy to produce audio > > buffer underruns while doing some compile job in the background. > > > > To be exact: I had vlc (1.1 git) play back several flac files and was compiling > > qt 4.7 in the background as a test w/ -j5 on an i7 860 . The result was that w/ > > the decreased granularity it caused noticeable audio buffer underruns while it > > worked just fine w/ the default granularity (nothing else touched). > > > > Just wanted to report this early on and hope it helps. > > Hi Matthias, > > Thanks for reporting this. I have a few more questions: > > Can you provide: > > you full kernel .config > > The config values of your sound card: > > cat /proc/asound/card0/pcm0p/sub0/hw_params > cat /proc/asound/card0/pcm0c/sub0/hw_params > > while you play your audio. (could be other than pcm0p, try to get one which is > not "Closed" while you play) Also providing the dmesg output showing which sound > card driver you are using might help. > > Also the output of: > cat /proc/cpuinfo > > Also, can you try reproducing the problem with different players ? With > non-git-bleeding-edge vlc versions too ? Can you reproduce this problem while > using "aplay" (a much simpler player) to play wav files ? (I've got an > instrumented version hooked on my tracer that traces underruns in here). Also, do you use pulseaudio, alsa directly, or go through OSS ? Mathieu > > Thanks ! > > Mathieu > > > > > So long, > > matthias. > > > > PS. Please cc' as I am not subscribed. Thanks a lot. > > -- > Mathieu Desnoyers > Operating System Efficiency R&D Consultant > EfficiOS Inc. > http://www.efficios.com -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com