From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755804AbXFXVri (ORCPT ); Sun, 24 Jun 2007 17:47:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752303AbXFXVr3 (ORCPT ); Sun, 24 Jun 2007 17:47:29 -0400 Received: from mga07.intel.com ([143.182.124.22]:11967 "EHLO azsmga101.ch.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751352AbXFXVr2 (ORCPT ); Sun, 24 Jun 2007 17:47:28 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.16,456,1175497200"; d="scan'208";a="242720462" Message-ID: <467EE609.9050908@linux.intel.com> Date: Sun, 24 Jun 2007 14:45:45 -0700 From: Arjan van de Ven User-Agent: Thunderbird 1.5 (Windows/20051201) MIME-Version: 1.0 To: Justin Piszcz CC: linux-kernel@vger.kernel.org, Alan Piszcz Subject: Re: IRQ Balance Question for Single but Multi-Core Processors References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Justin Piszcz wrote: > Question regarding the IRQ balance daemon and the 2.6.x kernel. > > For a single-processor but dual or quad core CPU, should one be running > the IRQ balancing daemon, will it result in increased performance? it's a tradeoff. for cores/threads that share cache, there's no point to run a daemon all the time, they share so many resources that things don't really matter..... irqbalance will, as a result, set up a one time static mapping and then exit on such systems; this will give a "reasonable" spread of interrupts, but won't cost you any cpu after that. On "real" smp systems, the performance and power tradeoffs are different and there irqbalance will keep an eye on things over time...