From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 27 May 2001 13:18:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 27 May 2001 13:18:49 -0400 Received: from penguin.e-mind.com ([195.223.140.120]:25376 "EHLO penguin.e-mind.com") by vger.kernel.org with ESMTP id ; Sun, 27 May 2001 13:18:34 -0400 Date: Sun, 27 May 2001 19:18:22 +0200 From: Andrea Arcangeli To: "David S. Miller" Cc: mingo@elte.hu, linux-kernel@vger.kernel.org, Linus Torvalds , Alan Cox , Alexey Kuznetsov Subject: Re: [patch] severe softirq handling performance bug, fix, 2.4.5 Message-ID: <20010527191822.J676@athlon.random> In-Reply-To: <15120.16986.610478.279574@pizda.ninka.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <15120.16986.610478.279574@pizda.ninka.net>; from davem@redhat.com on Sat, May 26, 2001 at 04:55:06PM -0700 X-GnuPG-Key-URL: http://e-mind.com/~andrea/aa.gnupg.asc X-PGP-Key-URL: http://e-mind.com/~andrea/aa.asc Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 26, 2001 at 04:55:06PM -0700, David S. Miller wrote: > And looking at the x86 code, I don't even understand how your fixes > can make a difference, what about the do_softirq() call in > arch/i386/kernel/irq.c:do_IRQ()??? That should be taking care of all > these "error cases" right? Yes, except when a softirq is marked running again under do_sofitrq (it is mostly an issue when the machine is otherwise idle that means we will waste cpu if we don't run the sofitrq immediatly, this problem was noticed by Manfred last month, but that is just a special case of the generic case of a softirq marked running again under do_softirq), and all those cases are supposed to be taken care by ksoftirqd. Andrea