From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 1 Jun 2002 13:06:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 1 Jun 2002 13:06:40 -0400 Received: from mailout08.sul.t-online.com ([194.25.134.20]:30640 "EHLO mailout08.sul.t-online.com") by vger.kernel.org with ESMTP id ; Sat, 1 Jun 2002 13:06:39 -0400 To: Mike Kravetz Cc: linux-kernel@vger.kernel.org, icollinson@imerge.co.uk, andrea@suse.de Subject: Re: realtime scheduling problems with 2.4 linux kernel >= 2.4.10 In-Reply-To: <20020531112847.B1529@w-mikek2.des.beaverton.ibm.com> From: Andi Kleen Date: 01 Jun 2002 19:05:47 +0200 Message-ID: User-Agent: Gnus/5.070095 (Pterodactyl Gnus v0.95) Emacs/20.7 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Mike Kravetz writes: > This works fine for me on 2.4.17 with a SERIAL console. Could this > be related to some differences (new features) in the VGA console? > I am totally ignorant of how the consoles work. One possibility is that something relies on schedule_task() - keventd doesn't run with realtime priority and can be starved. Seems to be the case indeed: /usr/src/linux/drivers/char% grep schedule_task *.c console.c: schedule_task(&console_callback_tq); ... the console switch does. Fixing it would require boosting keventd's priority either globally or temporarily. E.g. if the original reporter could put this (untested/uncompiled) at the beginning of kernel/context.c:context_thread(): current->policy = SCHED_RR; current->rt_priority = 99; it could fix his problem. -Andi