Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261375AbUJZRuA (ORCPT ); Tue, 26 Oct 2004 13:50:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261361AbUJZRs5 (ORCPT ); Tue, 26 Oct 2004 13:48:57 -0400 Received: from smtp1.Stanford.EDU ([171.67.16.123]:2232 "EHLO smtp1.Stanford.EDU") by vger.kernel.org with ESMTP id S261360AbUJZRrH (ORCPT ); Tue, 26 Oct 2004 13:47:07 -0400 Subject: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0 From: Fernando Pablo Lopez-Lezcano To: Lee Revell Cc: Rui Nuno Capela , Ingo Molnar , Florian Schmidt , "K.R. Foley" , linux-kernel@vger.kernel.org, mark_h_johnson@raytheon.com, Bill Huey , Adam Heath , Thomas Gleixner , Michal Schmidt , Alexander Batyrshin , Fernando Pablo Lopez-Lezcano In-Reply-To: <1098811515.10048.5.camel@krustophenia.net> References: <20041022155048.GA16240@elte.hu> <20041022175633.GA1864@elte.hu> <20041025104023.GA1960@elte.hu> <417CDE90.6040201@cybsft.com> <20041025111046.GA3630@elte.hu> <20041025121210.GA6555@elte.hu> <20041025152458.3e62120a@mango.fruits.de> <20041025132605.GA9516@elte.hu> <20041025160330.394e9071@mango.fruits.de> <20041025141008.GA13512@elte.hu> <20041025141628.GA14282@elte.hu> <33313.192.168.1.5.1098733224.squirrel@192.168.1.5> <1098759671.9166.10.camel@krustophenia.net> <1098767513.2926.3.camel@cmn37.stanford.edu> <1098811515.10048.5.camel@krustophenia.net> Content-Type: text/plain Organization: Message-Id: <1098812749.5615.15.camel@cmn37.stanford.edu> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 (1.2.2-5) Date: 26 Oct 2004 10:45:49 -0700 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2424 Lines: 53 On Tue, 2004-10-26 at 10:25, Lee Revell wrote: > On Mon, 2004-10-25 at 22:11 -0700, Fernando Pablo Lopez-Lezcano wrote: > > On Mon, 2004-10-25 at 20:01, Lee Revell wrote: > > > On Mon, 2004-10-25 at 20:40 +0100, Rui Nuno Capela wrote: > > > > OTOH, jackd -R xruns are awfully back, even thought I (re)prioritize the > > > > relevant IRQ thread handlers to be always higher than jackd's. > > > > > > Actually they should be lower, except the soundcard. I was only able to > > > get the xrun free behavior of T3 by setting all IRQ threads except the > > > soundcard to SCHED_OTHER. Especially important was setting ksoftirqd to > > > SCHED_OTHER, this actually may have been the only one necessary. > > > > > > The relative priorities of jackd and the soundcard irq do not matter as > > > these two should never contend (aka they are never both runnable at the > > > same time). > > > > What happens when one is blessed with a laptop where everything is > > sharing an interrupt? > > > > $ cat /proc/interrupts > > CPU0 > > 0: 2372239 XT-PIC timer 0/72239 > > 1: 5362 XT-PIC i8042 0/5362 > > 2: 0 XT-PIC cascade 0/0 > > 8: 1 XT-PIC rtc 0/1 > > 9: 616176 XT-PIC acpi, uhci_hcd, uhci_hcd, uhci_hcd, > > eth0, yenta, yenta, Intel 82801CA-ICH3, radeon@PCI:1:0:0 0/16176 > > 11: 37 XT-PIC sonypi 0/35 > > 12: 28392 XT-PIC i8042 0/28392 > > 14: 21078 XT-PIC ide0 0/21078 > > 15: 472 XT-PIC ide1 0/472 > > Ugh, why would _anyone_ design a laptop like that? You have 4 > perfectly good interrupts that you are not using at all. Is it really > cheaper to put everything on the same irq? Does this work better under > Windows or something? > > AFAIK there is nothing you can do - any other irq that fires on 9 will > mask out all the others until it completes. Yes, except I did not see all these xruns running 2.4.26 + lowlat + preempt (same machine). Things got better with 2.6.x up to, perhaps, S7, although I would have to retest to make sure. Now they seem to be worse than before. -- Fernando - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/