From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750796AbWDQNKd (ORCPT ); Mon, 17 Apr 2006 09:10:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750815AbWDQNKc (ORCPT ); Mon, 17 Apr 2006 09:10:32 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:17359 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1750796AbWDQNKc (ORCPT ); Mon, 17 Apr 2006 09:10:32 -0400 Subject: Re: irqbalance mandatory on SMP kernels? From: Arjan van de Ven To: "Robert M. Stockmann" Cc: linux-kernel@vger.kernel.org, Randy Dunlap , Linus Torvalds , Andrew Morton , Andre Hedrick , Manfred Spraul , Alan Cox , Kamal Deen In-Reply-To: References: Content-Type: text/plain Date: Mon, 17 Apr 2006 15:10:22 +0200 Message-Id: <1145279422.2847.44.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > [jackson:stock]:(/usr/src/linux)$ cat /proc/interrupts > CPU0 CPU1 > 0: 3139568 0 IO-APIC-edge timer > 1: 8923 0 IO-APIC-edge i8042 > 3: 10 0 IO-APIC-edge serial > 4: 37 0 IO-APIC-edge serial > 8: 0 0 IO-APIC-edge rtc > 9: 240 0 IO-APIC-level acpi > 12: 75316 0 IO-APIC-edge i8042 > 14: 64291 0 IO-APIC-edge ide0 > 15: 64291 0 IO-APIC-edge ide1 > 16: 235408 0 IO-APIC-level HiSax, nvidia > 17: 15823 0 IO-APIC-level libata, AMD AMD8111 > 19: 241 0 IO-APIC-level ohci_hcd, ohci_hcd, ohci1394 > 24: 50761 0 IO-APIC-level eth0 > NMI: 89 28 > LOC: 3139042 3139125 > ERR: 0 > MIS: 0 > [jackson:stock]:(/usr/src/linux)$ this may or may not be a problem depending on how long a time you used to collect this. Based on your timer tick count it really looks like your irq rates are so low that it really doesn't matter much > > Only when firing up the irqbalance util at boot time will activate > true SMP, distributing IRQ's across CPU's. Is this on purpose? > Because afaik a Linux SMP kernel, 2.4.xx or 2.6.xx should always > result in distributed IRQ loads across CPU's. that is a chipset feature if it happens; not all chipsets do this (and most that do, do it badly). I'm not sure what your actual problem is btw, the irqbalance tool is supposed to automatically start at boot, did it not do that ? (and no the kernel doesn't need to do everything, something like this can perfectly well be done in userspace as irqbalance shows)