From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262294AbVFUWkk (ORCPT ); Tue, 21 Jun 2005 18:40:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262421AbVFUWji (ORCPT ); Tue, 21 Jun 2005 18:39:38 -0400 Received: from mxfep02.bredband.com ([195.54.107.73]:60610 "EHLO mxfep02.bredband.com") by vger.kernel.org with ESMTP id S262294AbVFUWPl (ORCPT ); Tue, 21 Jun 2005 18:15:41 -0400 Message-ID: <42B8919A.1080109@bredband.net> Date: Wed, 22 Jun 2005 00:15:54 +0200 From: =?ISO-8859-1?Q?Patrik_H=E4gglund?= User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206) X-Accept-Language: en-us, en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: Steven Rostedt , Chris Friesen Subject: Re: SCHED_RR/SCHED_FIFO and kernel threads? References: <42B199FF.5010705@bredband.net> <42B19F65.6000102@nortel.com> <42B26FF8.6090505@bredband.net> <1119011872.4846.12.camel@localhost.localdomain> <42B3D7E2.2070600@bredband.net> In-Reply-To: <42B3D7E2.2070600@bredband.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Well, Ingo's patch didn't made any difference for my problem with kernel starvation. As expected, the workaround of raising the priority of the 'events' kernel thread made it possible to switch VT or switch windows in X (as described in my first mail), when running a simple infinite loop. When running arbitrary programs, I expect that all kernel threads needs higher priority. I guess that the point with kernel threads is to push heavy kernel requests "backwards in the queue", thereby lowering the mean latency for SHED_OTHER processes. Therefore, using high priorities for kernel threads was not an option. However, this comes at the price of breaking SCHED_FIFO/SCHED_RR. The only clean solution is probably to have priorities that are reserved for kernel threads. I saw that kernel threads in LynxOS may use a priority of 1/2 above of the user-space tasks it serves. This seems like a good solution to the problem. Any other patches out there, ready for a test? /Patrik Hägglund