From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264098AbTEOVQC (ORCPT ); Thu, 15 May 2003 17:16:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264237AbTEOVQC (ORCPT ); Thu, 15 May 2003 17:16:02 -0400 Received: from pc3-cmbg5-6-cust177.cmbg.cable.ntl.com ([81.104.203.177]:35570 "EHLO flat") by vger.kernel.org with ESMTP id S264098AbTEOVQB (ORCPT ); Thu, 15 May 2003 17:16:01 -0400 Date: Thu, 15 May 2003 22:29:45 +0100 From: cb-lkml@fish.zetnet.co.uk To: linux-kernel@vger.kernel.org Subject: O(1) scheduler questions + bug Message-ID: <20030515212945.GA617@fish.zetnet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi all I started writing this email a while ago, the Doom III trailer example/bug has prompted me to finish it. Firstly, in -mm MAX_SLEEP_AVG defaults to 10 seconds. This means that a new interactive task has a relatively low priority for nearly 5 seconds which feels too long in practise. (eg start ogg123, music starts, switch desktop, music skips) I think that MAX_SLEEP_AVG should be reduced to allow the scheduler to react quicker. Secondly, if there are (hypothetically) two interactive tasks, one repeatedly works for 10ms and then sleeps for 90ms, and the other works for 45ms and sleeps for 55ms, then they get the same maximum priority even though one is "more interactive" than the other (using 10% of CPU rather than 45%). Has this been considered in the design of the effective_prio function? Does it matter? Finally, playing the Doom III trailer with mplayer results in mplayer's priority slowly increasing to the maximum and therefore becoming non-interactive, which means a CPU hog (perl -e 'while (1) {}') can cause the audio/video playback to skip. Mplayer consumes about 25% of CPU, X consumes about 10%. (measured with top) I'm currently using 2.5.69-mm2, Celeron 333, pre-empt. Charlie