From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266129AbUHRMZC (ORCPT ); Wed, 18 Aug 2004 08:25:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266147AbUHRMZB (ORCPT ); Wed, 18 Aug 2004 08:25:01 -0400 Received: from pD951734E.dip.t-dialin.net ([217.81.115.78]:49030 "EHLO undata.org") by vger.kernel.org with ESMTP id S266129AbUHRMX0 (ORCPT ); Wed, 18 Aug 2004 08:23:26 -0400 Subject: Re: [patch] voluntary-preempt-2.6.8.1-P2 From: Thomas Charbonnel To: Ingo Molnar Cc: Lee Revell , Florian Schmidt , linux-kernel , Felipe Alfaro Solana In-Reply-To: <20040816120933.GA4211@elte.hu> References: <20040816023655.GA8746@elte.hu> <1092624221.867.118.camel@krustophenia.net> <20040816032806.GA11750@elte.hu> <20040816033623.GA12157@elte.hu> <1092627691.867.150.camel@krustophenia.net> <20040816034618.GA13063@elte.hu> <1092628493.810.3.camel@krustophenia.net> <20040816040515.GA13665@elte.hu> <1092654819.5057.18.camel@localhost> <20040816113131.GA30527@elte.hu> <20040816120933.GA4211@elte.hu> Content-Type: text/plain Message-Id: <1092831726.5777.160.camel@localhost> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Wed, 18 Aug 2004 14:22:07 +0200 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote : > here's -P2: > > http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8.1-P2 > > Changes since -P1: > > - trace interrupted kernel code (via hardirqs, NMIs and pagefaults) > > - yet another shot at trying to fix the IO-APIC/USB issues. > > - mcount speedups - tracing should be faster > > Ingo > - The next problem I have relates to irq sharing. On my laptop I can't avoid it : 10: 1070631 XT-PIC yenta, yenta, uhci_hcd, Intel 82801CA-ICH3, hdsp, eth0 If I set the sound card's interrupt to be non threaded, then I get a rather long non preemptible section : http://www.undata.org/~thomas/irq_sharing.trace As a side note, and this has already been reported here several times, the SA_INTERRUPT flag set notably by the sound card drivers handlers is not honored on current kernels if the device is not the first one to be registered. A simple fix would be to add SA_INTERRUPT handlers at the beginning instead of the end of the irq queue in setup_irq. Similarly, when using SA_SAMPLE_RANDOM, all devices on the given irq contribute to the entropy, even those that have a predictable interrupt rate (e.g. sound cards), and/or for which the number of interrupts could outweight the number of interrupts of the original SA_SAMPLE_RANDOM driver. Thomas