From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030363AbXCLPSk (ORCPT ); Mon, 12 Mar 2007 11:18:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030370AbXCLPSk (ORCPT ); Mon, 12 Mar 2007 11:18:40 -0400 Received: from zrtps0kn.nortel.com ([47.140.192.55]:51611 "EHLO zrtps0kn.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030363AbXCLPSj (ORCPT ); Mon, 12 Mar 2007 11:18:39 -0400 Message-ID: <45F56F37.6090407@nortel.com> Date: Mon, 12 Mar 2007 09:18:15 -0600 From: "Chris Friesen" User-Agent: Mozilla Thunderbird 1.0.2-6 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Con Kolivas CC: Robert Love , Ingo Molnar , Linus Torvalds , Linux kernel , Andrew Morton Subject: Re: resend: KERNEL BUG: nice level should not affect SCHED_RR timeslice References: <45EF4890.6020806@nortel.com> <200703122027.17219.kernel@kolivas.org> In-Reply-To: <200703122027.17219.kernel@kolivas.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 12 Mar 2007 15:18:19.0281 (UTC) FILETIME=[AA559010:01C764B9] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Con Kolivas wrote: > Indeed we do change timeslice with nice on rt_tasks in mainline at the moment. > Truth is most rt programming couldn't care less about timeslices, but your > point about it deviating from the standard is valid. RSDL does not change > timeslice with nice on SCHED_RR tasks so it's sort of getting addressed by > proxy. Unfortunately we have some vendor-supplied software that does care about timeslices. It's a crazy thing with multiple SCHED_RR kernel threads that don't really self-manage very well. They're spawned by a SCHED_OTHER task and inherit its nice level. We modified the startup for the spawning task to run it at a lower nice level and were fairly surprised when the latency of message handling went way up. Chris