From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753720AbYI1U4l (ORCPT ); Sun, 28 Sep 2008 16:56:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752037AbYI1U4e (ORCPT ); Sun, 28 Sep 2008 16:56:34 -0400 Received: from pih-relay08.plus.net ([212.159.14.20]:45517 "EHLO pih-relay08.plus.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752006AbYI1U4d (ORCPT ); Sun, 28 Sep 2008 16:56:33 -0400 Message-ID: <48DFEF8A.3000502@yahoo.com> Date: Sun, 28 Sep 2008 21:56:42 +0100 From: Sitsofe Wheeler User-Agent: Thunderbird 2.0.0.16 (Macintosh/20080707) MIME-Version: 1.0 To: Ingo Molnar CC: linux-kernel@vger.kernel.org, Peter Zijlstra , Arjan van de Ven , Steven Rostedt Subject: Re: How how latent should non-preemptive scheduling be? References: <48D39312.9000400@yahoo.com> <20080922115749.GE14301@elte.hu> <48D88DB4.9020003@yahoo.com> <20080923115323.GA27240@elte.hu> <48D919A9.5000708@yahoo.com> <48D9460C.5040504@yahoo.com> <48D96725.1080909@yahoo.com> <20080927204834.GA31650@elte.hu> In-Reply-To: <20080927204834.GA31650@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Plusnet-Relay: 441ecf478467fd0cb2beace28f47524b Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > does it get better if you have CONFIG_PREEMPT_VOLUNTARY=y enabled? That CONFIG_PREEMPT_VOLUNTARY=y has always been enabled in these results. > _should_ break up this section neatly. If it doesnt then please add a > might_sleep() check to kernel/kernel/semaphore.c's down_timeout() > function - that is called a number of times in this trace. I added might_sleep() to the start of down_timeout() but it neither printed anything to dmesg nor changed the latency issue... Strangely stalling only seems to turn up in linux-tip kernels with very little debugging options set within them. I have a linux-tip that has lots of extra debugging options set and this problem doesn't show up... I've also asked about this on the ACPI mailing list and had a huge amount of help from finding a good point for a cond_resched - http://marc.info/?l=linux-acpi&m=122236450105747&w=2 . Certain things (like games) still stutter when the battery is read but it's enough to play back sound in rhythmbox without stuttering. Any ideas why the issue would go away with a debug kernel though? -- Sitsofe | http://sucs.org/~sits/