Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751351AbWJMAEY (ORCPT ); Thu, 12 Oct 2006 20:04:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751350AbWJMAEX (ORCPT ); Thu, 12 Oct 2006 20:04:23 -0400 Received: from mx1.redhat.com ([66.187.233.31]:42646 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S1751351AbWJMAEW (ORCPT ); Thu, 12 Oct 2006 20:04:22 -0400 Date: Thu, 12 Oct 2006 20:03:47 -0400 From: Dave Jones To: "Chen, Kenneth W" Cc: "'Zach Brown'" , "'Suparna Bhattacharya'" , "Lahaise, Benjamin C" , linux-kernel@vger.kernel.org, linux-aio Subject: Re: [patch] rearrange kioctx and aio_ring_info Message-ID: <20061013000347.GA8673@redhat.com> Mail-Followup-To: Dave Jones , "Chen, Kenneth W" , 'Zach Brown' , 'Suparna Bhattacharya' , "Lahaise, Benjamin C" , linux-kernel@vger.kernel.org, linux-aio References: <000101c6ee55$c3e121a0$db34030a@amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000101c6ee55$c3e121a0$db34030a@amr.corp.intel.com> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1073 Lines: 23 On Thu, Oct 12, 2006 at 04:25:54PM -0700, Chen, Kenneth W wrote: > The following patch is result of our kernel data latency analysis on a > large database setup (128 logical CPU, 1 TB memory, a couple thousand > disks). The analysis is done at an individual cache line level through > hardware performance monitor unit. What we did essentially is to collect > data access latency on every kernel memory address and look for top 50 > longest average access latency. The hardware performance unit also keeps > track of instruction address for each collected data access. This allows > us to further associate each of the top 50 cache lines to instruction > sequences that caused long latency. Do you have performance numbers of before/after this change ? How much is it worth? Dave -- http://www.codemonkey.org.uk - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/