From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263778AbTJ0XtH (ORCPT ); Mon, 27 Oct 2003 18:49:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263780AbTJ0Xs4 (ORCPT ); Mon, 27 Oct 2003 18:48:56 -0500 Received: from fw.osdl.org ([65.172.181.6]:41444 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S263778AbTJ0Xss (ORCPT ); Mon, 27 Oct 2003 18:48:48 -0500 Date: Mon, 27 Oct 2003 15:49:11 -0800 From: Dave Olien To: rwhron@earthlink.net, piggin@cyberone.com.au Cc: linux-kernel@vger.kernel.org, akpm@osdl.org Subject: Re: [BENCHMARK] I/O regression after 2.6.0-test5 Message-ID: <20031027234911.GA31491@osdl.org> References: <20031026103829.GA6549@rushmore> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="M9NhX3UHpAaciwkO" Content-Disposition: inline In-Reply-To: <20031026103829.GA6549@rushmore> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --M9NhX3UHpAaciwkO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sun, Oct 26, 2003 at 05:38:29AM -0500, rwhron@earthlink.net wrote: > 2.6.0-test8-mm1 doesn't have the AIM7 database regression > that 2.6.0-test8 has. The AIM7 fileserver and shared > workloads regression between test5-mm2 and test8-mm1 is > about 18%. Mainline regression was about 38% between test5 > and test8 on AIM7 fileserver and shared workloads. > Yes, I've noticed this as well. This has been the pattern since test5. Every mainline release (test6, test7, test8, AND test9) has a large regression in as-iosched vs deadline scheduler performance. The regression is considerably smaller when the mm[1-4] patches are applied. See the attachment for a collection of data points, collected running REAIM, an updated version of AIM7. In the mm[1-4] broken-out patches lists, there is an O_SYNC-SPEEDUP-2.patch that has been in all of the mm[1-4] patches since test5. The comments at the head of that patch says this patch reduces the blocking of writers on i_sem. This patch probably allows more writer concurrency. This benefits only O_SYNC writes. Reaim does O_SYNC writes. My guess this patch is what reduces the as-iosched regression for mm[1-4] patched kernels. I imagine the O_SYNC-SPEEDUP is unlikely to get into any more TEST kernels. But maybe it gives a hint is to what's going on with as-iosched. Letting in more concurrent writers seems to reduce as-iosched's peformance regression. --M9NhX3UHpAaciwkO Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename=reaim_as_vs_deadline Some data points (marked with XXX) haven't been collected yet. This data has been collected on the Scalable Test Platform (STP) 8-way machines at OSDL. REAIM is an updated version of AIM7. Information on REAIM and performance data collected on 2, 4, and 8 way machines can be found at http://developer.osdl.org/cliffw/ Hardware details of the STP 8-way machine are at the bottom of this page. More details on each test run can be viewed by construcing a URL from the STP ID #. For example, the first entry in the table can be seen at URL http://khack.osdl.org/279446 Maximum Jobs Per Minute Kernel Version IO Scheduler STP ID # Peak Load Quick Convergence 2.6.0-test5 Deadline 279446 8950 8542 As-iosched 279444 8785 8489 mm1 Deadline 279560 8303 7998 As-iosched 279558 8401 7935 mm2 Deadline 279929 8309 8063 As-iosched 281948 8224 7741 mm3 Deadline 281859 8438 8064 As-iosched 281813 8207 7879 mm4 Deadline 281814 8222 7991 As-iosched 281815 8417 7963 2.6.0-test6 Deadline 281816 8302 7949 **** As-iosched 281817 6934 6945 mm1 Deadline 281864 8375 7930 As-iosched 281863 8163 7923 mm2 Deadline 281948 8224 7741 As-iosched 281865 8309 7616 mm3 Deadline 281868 8280 8022 As-iosched 281867 8348 8017 mm4 Deadline 281870 8512 7868 As-iosched 281869 8307 7749 2.6.0-test7 Deadline 281231 8413 8002 **** As-iosched 282095 6957 6790 mm1 Deadline 281548 8567 8033 As-iosched 282181 8346 7755 2.6.0-test8 Deadline 281671 8294 8020 **** As-iosched 281669 7018 6926 mm1 Deadline 282183 8326 7997 As-iosched 282182 8347 XXX 2.6.0-test9 Deadline XXXX XXXX As-iosched 282310 6868 6045 **** --M9NhX3UHpAaciwkO--