From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755238AbYIEQT1 (ORCPT ); Fri, 5 Sep 2008 12:19:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753813AbYIEQTS (ORCPT ); Fri, 5 Sep 2008 12:19:18 -0400 Received: from g1t0026.austin.hp.com ([15.216.28.33]:4833 "EHLO g1t0026.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753591AbYIEQTR (ORCPT ); Fri, 5 Sep 2008 12:19:17 -0400 Message-ID: <48C15C02.7060504@hp.com> Date: Fri, 05 Sep 2008 12:19:14 -0400 From: "Alan D. Brunelle" User-Agent: Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: "linux-kernel@vger.kernel.org" CC: Jens Axboe Subject: Benchmarking results: DSS elapsed time values w/ rq_affinity=0/1 - Jens' for-2.6.28 tree Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some DSS results from a 32-way ia64 machine set up to try and analyze Oracle OLTP & DSS loads (128GB RAM, >200 disks). The data collected was the elapsed time for DSS runs w/ 128 MBRs and 128 Readers, running on a kernel generated from Jens Axboe's origin/for-2.6.28 tree. I alternated runs, setting rq_affinity to 0 and 1 for all disks at the beginning of each run. There are a total of 68 data points for each alternative, and the overall results show a decided improvement for this type of load with rq_affinity set to 1: rq=0: min=27.440000 avg=27.980500 max=28.500000 sdev=0.296827 rq=1: min=26.900000 avg=27.071500 max=27.480000 sdev=0.125169 Not only do we see about a 3.25% improvement in reduced average time, we also see that the run-to-run deviations are much smaller as well. For a pictorial representation, check out the graph @ http://free.linux.hp.com/~adb/jens/08-09-05/dss.png The red and green areas illustrate the delta from the average for all the data points with that rq_affinity setting. (Red being rq_affinity=0, green being rq_affinity=1.) I collected some vmstat & iostat data, and will be evaluating that as well, and perhaps looking into lockstat & profiling data (time permitting). The system has been set up as part of a collaboration between HP & Red Hat's Linux performance teams, and we've been using it to analyze performance characteristics of Oracle loads on large-ish systems, as well as for evaluating potential code changes. Alan D. Brunelle HP Linux Kernel Technology Team