From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267804AbUHRVaB (ORCPT ); Wed, 18 Aug 2004 17:30:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267800AbUHRVaA (ORCPT ); Wed, 18 Aug 2004 17:30:00 -0400 Received: from ultra7.eskimo.com ([204.122.16.70]:59141 "EHLO ultra7.eskimo.com") by vger.kernel.org with ESMTP id S267799AbUHRV3e (ORCPT ); Wed, 18 Aug 2004 17:29:34 -0400 Date: Wed, 18 Aug 2004 14:29:11 -0700 From: Elladan To: Florian Schmidt Cc: Ingo Molnar , Lee Revell , Thomas Charbonnel , linux-kernel , Felipe Alfaro Solana Subject: Re: [patch] voluntary-preempt-2.6.8.1-P3 Message-ID: <20040818212911.GA26965@eskimo.com> References: <1092628493.810.3.camel@krustophenia.net> <20040816040515.GA13665@elte.hu> <1092654819.5057.18.camel@localhost> <20040816113131.GA30527@elte.hu> <20040816120933.GA4211@elte.hu> <1092716644.876.1.camel@krustophenia.net> <20040817080512.GA1649@elte.hu> <20040818141231.4bd5ff9d@mango.fruits.de> <20040818122703.GA17301@elte.hu> <20040818150148.4d2c56ec@mango.fruits.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040818150148.4d2c56ec@mango.fruits.de> User-Agent: Mutt/1.5.6+20040523i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 18, 2004 at 03:01:48PM +0200, Florian Schmidt wrote: > On Wed, 18 Aug 2004 14:27:03 +0200 > Ingo Molnar wrote: > > > > > Btw: one question: at one point in time the IRQ handlers were in the > > > SCHED_FIFO scheduling class. Why has this changed? > > > > so that they dont starve the audio threads by default - the audio IRQ > > has to get another priority anyway. Maybe we could try a default > > SCHED_FIFO prio lower than the typical rt_priority of jackd - e.g. 30? > > Oh, upon rereading the chrt manpage i found out why i failed to set them > to SCHED_FIFO manually. So it was my error. I thought the > scheduling of the IRQ handlers was not changable at runtime. Thus my > question to make them SCHED_FIFO by default. > > Well, i still think they should be SCHED_FIFO by default, so no user > process that is not itself SCHED_FIFO can starve them [X11 was able to > starve mouse irq's on my system with the defualt IRQ handlers > running SCHED_OTHER FWIW]. To make starving of user-SCHED_FIFO processes > unprobably maybe use a default static prio of 0. > > Afaik jackd uses priorities > 0 for its audio threads when runing > SCHED_FIFO anyways.. > > But since the user will have to tweak his IRQ handlers manually anyways > [set soundcard irq higher prio than the rest, etc..], it doesn't really > make a difference. This doesn't take into account SCHED_RR processes, which expect to behave just like SCHED_FIFO unless there's another SCHED_RR process of the same priority... -J