From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755605Ab0IROxG (ORCPT ); Sat, 18 Sep 2010 10:53:06 -0400 Received: from mail.openrapids.net ([64.15.138.104]:39129 "EHLO blackscsi.openrapids.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755584Ab0IROxE (ORCPT ); Sat, 18 Sep 2010 10:53:04 -0400 Date: Sat, 18 Sep 2010 10:53:01 -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: <20100918145301.GA19879@Krystal> References: <201009162048.50941.ml_kernel@mortal-soul.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201009162048.50941.ml_kernel@mortal-soul.de> X-Editor: vi X-Info: http://www.efficios.com X-Operating-System: Linux/2.6.26-2-686 (i686) X-Uptime: 10:45:49 up 238 days, 17:22, 4 users, load average: 0.11, 0.08, 0.05 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 * 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). 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