From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757375Ab0CaWbL (ORCPT ); Wed, 31 Mar 2010 18:31:11 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:40504 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756619Ab0CaWbI (ORCPT ); Wed, 31 Mar 2010 18:31:08 -0400 Date: Thu, 1 Apr 2010 00:31:06 +0200 From: Michael Grzeschik To: linux-kernel@vger.kernel.org Cc: rsc@pengutronix.de Subject: Issues with Patch: "sched: Improve latencies and throughput" Message-ID: <20100331223106.GJ10342@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 21:22:48 up 11 days, 8:12, 23 users, load average: 1.72, 2.70, 2.49 User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: 2001:6f8:1178:2:215:17ff:fe12:23b0 X-SA-Exim-Mail-From: mgr@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We are using an arm mx31 embedded cpu with the v2.6.34 Kernelrelease and realized some issues with the scheduling behaviour the patch "sched: Improve latencies and throughput" [1] by Mike Galbraith introduced to the kernel. When we used the alsa utility aplay to pipe some audio through an usbaudio device and put some scheduling overhead on the device, the amount of underruns, due to the not fast enough refilled ring buffer, was noticable increased with that patch [1] applied. Until we reverse applied the patch the amount of underruns was appreciable lower. That in fact is the opposite behaviour to its actual meaning. [1] 0ec9fab3d186d9cbb00c0f694d4a260d07c198d9 mgr -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |