From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266552AbUAOLok (ORCPT ); Thu, 15 Jan 2004 06:44:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266558AbUAOLoj (ORCPT ); Thu, 15 Jan 2004 06:44:39 -0500 Received: from [160.218.214.150] ([160.218.214.150]:4224 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S266552AbUAOLoe (ORCPT ); Thu, 15 Jan 2004 06:44:34 -0500 Date: Thu, 15 Jan 2004 12:43:46 +0100 From: Pavel Machek To: Joe Korty Cc: Arjan van de Ven , Ethan Weinstein , linux-kernel@vger.kernel.org, William Lee Irwin III Subject: Re: 2.6.1 and irq balancing Message-ID: <20040115114346.GB9265@elf.ucw.cz> References: <40008745.4070109@stinkfoot.org> <1073814681.4431.5.camel@laptop.fenrus.com> <20040111165012.GA24746@tsunami.ccur.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040111165012.GA24746@tsunami.ccur.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > Greetings all, > > > > > > I upgraded my server to 2.6.1, and I'm finding I'm saddled with only > > > interrupting on CPU0 again. 2.6.0 does this as well. This is the > > > Supermicro X5DPL-iGM-O (E7501 chipset), 2 Xeons@2.4ghz HT enabled. > > > /proc/cpuinfo is normal as per HT, displaying 4 cpus. > > > > you should run the userspace irq balance daemon: > > http://people.redhat.com/arjanv/irqbalance/ > > I have long wondered what is so evil about most interrupts going to > CPU 0 that we felt we had to have a pair of irqdaemons in 2.6. From my > (admittedly imperfect) experience, the APIC will route an interrupt to > CPU 1 if CPU 0 is busy with another interrupt, to CPU 2 if 0 and 1 are > so occupied, and so on. I see no harm in this other than the strangely > lopsided /proc/interrupt displays, which I can live with. Well, imagine 8 CPU machine with high interrupt load. Poor process that gets scheduled on CPU#0 does little progress, but is shown as eating one whole CPU. Pavel -- When do you have a heart between your knees? [Johanka's followup: and *two* hearts?]