From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262192AbTE0BCl (ORCPT ); Mon, 26 May 2003 21:02:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262195AbTE0BCl (ORCPT ); Mon, 26 May 2003 21:02:41 -0400 Received: from deviant.impure.org.uk ([195.82.120.238]:14506 "EHLO deviant.impure.org.uk") by vger.kernel.org with ESMTP id S262192AbTE0BCJ (ORCPT ); Mon, 26 May 2003 21:02:09 -0400 Date: Tue, 27 May 2003 02:16:20 +0100 From: Dave Jones To: Andrea Arcangeli Cc: "David S. Miller" , akpm@digeo.com, davidsen@tmr.com, haveblue@us.ibm.com, habanero@us.ibm.com, mbligh@aracnet.com, linux-kernel@vger.kernel.org Subject: Re: userspace irq balancer Message-ID: <20030527011620.GB7135@suse.de> Mail-Followup-To: Dave Jones , Andrea Arcangeli , "David S. Miller" , akpm@digeo.com, davidsen@tmr.com, haveblue@us.ibm.com, habanero@us.ibm.com, mbligh@aracnet.com, linux-kernel@vger.kernel.org References: <20030527000639.GA3767@dualathlon.random> <20030526.171527.35691510.davem@redhat.com> <20030527004115.GD3767@dualathlon.random> <20030526.174841.116378513.davem@redhat.com> <20030527010903.GF3767@dualathlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030527010903.GF3767@dualathlon.random> User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 27, 2003 at 03:09:03AM +0200, Andrea Arcangeli wrote: > > So I'm asking you, again, how are you going to measure softirq load in > > making hardware IRQ load balancing decisions? Watching the scheduling > > rdtsc could do it very well, irqs and softirqs can't be rescheduled so > you can tick measure how long you take in each cpu On CPUs that vary frequency, this will break, unless TSC scales with frequency. You cannot assume that this will be the case. Dave