From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263851AbUE1UA5 (ORCPT ); Fri, 28 May 2004 16:00:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263843AbUE1T7s (ORCPT ); Fri, 28 May 2004 15:59:48 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:42398 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S263826AbUE1T6y (ORCPT ); Fri, 28 May 2004 15:58:54 -0400 Message-ID: <40B799EB.8060000@pobox.com> Date: Fri, 28 May 2004 15:58:35 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040510 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Nivedita Singhvi CC: Arjan van de Ven , "Martin J. Bligh" , "Nakajima, Jun" , Andrew Morton , Anton Blanchard , linux-kernel@vger.kernel.org Subject: Re: CONFIG_IRQBALANCE for AMD64? References: <7F740D512C7C1046AB53446D372001730182BAE2@scsmsx402.amr.corp.intel.com> <40B7797F.2090204@pobox.com> <17750000.1085766378@flay> <20040528175724.GC9898@devserv.devel.redhat.com> <40B7984E.7040208@us.ibm.com> In-Reply-To: <40B7984E.7040208@us.ibm.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nivedita Singhvi wrote: > I see networking interrupts requiring fine granularity > balancing, to avoid the potential for dropped packets and > long latencies. That is, given a busy server that is > seeing a lot of interrupts, fair distribution of the > interrupts is required within a very small amount of time, > and we cannot require a user space daemon that parses the /proc > file system and applies a policy and then rebinds irqs > to different CPUs to run with that frequency. Network is one of the areas where you _don't_ want to be constantly pointing your NIC's irq to different CPUs. Cache affinity, packet re-ordering problems, and other fun ensue. Jeff