Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764436AbXEUPLi (ORCPT ); Mon, 21 May 2007 11:11:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764163AbXEUPLR (ORCPT ); Mon, 21 May 2007 11:11:17 -0400 Received: from sceptre.pobox.com ([207.106.133.20]:54796 "EHLO sceptre.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764149AbXEUPLP (ORCPT ); Mon, 21 May 2007 11:11:15 -0400 Message-ID: <4651B68E.6050308@hp.com> Date: Mon, 21 May 2007 11:11:10 -0400 From: "Alan D. Brunelle" Reply-To: Alan.Brunelle@hp.com User-Agent: Thunderbird 1.5.0.10 (X11/20070403) MIME-Version: 1.0 To: Jens Axboe Cc: linux-kernel@vger.kernel.org, vtaras@openvz.org Subject: Re: CFQ IO scheduler patch series - AIM7 DBase results on a 16-way IA64 References: <4635D59C.4050300@hp.com> <20070430122753.GL21015@kernel.dk> <46372C8B.7090901@hp.com> <20070501121139.GA4653@kernel.dk> <46518D8A.10609@hp.com> <20070521121944.GU14746@kernel.dk> In-Reply-To: <20070521121944.GU14746@kernel.dk> 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 Content-Length: 2633 Lines: 72 Jens Axboe wrote: > On Mon, May 21 2007, Alan D. Brunelle wrote: > >> Jens Axboe wrote: >> >>> On Tue, May 01 2007, Alan D. Brunelle wrote: >>> >>> >>>> Jens Axboe wrote: >>>> >>>> >>>>> On Mon, Apr 30 2007, Alan D. Brunelle wrote: >>>>> >>>>> >>>>>> The results from a single run of an AIM7 DBase load on a 16-way ia64 >>>>>> box (64GB RAM + 144 FC disks) showed a slight regression (~0.5%) by >>>>>> adding in this patch. (Graph can be found at >>>>>> http://free.linux.hp.com/~adb/cfq/cfq_dbase.png ) It is only a single >>>>>> set of runs, on a single platform, but it is something to keep an eye >>>>>> on as the regression showed itself across the complete run. >>>>>> >>>>>> >>>>> Do you know if this regression is due to worse IO performance, or >>>>> increased system CPU usage? >>>>> >>>>> >>>> We performed two point runs yesterday (20,000 and 50,000 tasks) and here >>>> are the results: >>>> >>>> Kernel Tasks Jobs per Minute %sys (avg) >>>> ------ ----- --------------- ---------- >>>> 2.6.21 20000 60,831.1 39.83% >>>> CFQ br 20000 60,237.4 40.80% >>>> -0.98% +2.44% >>>> >>>> 2.6.21 50000 60,881.6 40.43% >>>> CFQ br 50000 60,400.6 40.80% >>>> -0.79% +0.92% >>>> >>>> So we're seeing a slight IO performance regression with a slight >>>> increase in %system with the CFQ branch. (A chart of the complete run >>>> values is up on http://free.linux.hp.com/~adb/cfq/cfq_20k50k.png ). >>>> >>>> >>> Alan, can you repeat that same run with this patch applied? It >>> reinstates the cfq lookup hash, which could account for increased system >>> utilization. >>> >>> >> Hi Jens - >> >> This test was performed over the weekend, results are updated on >> >> http://free.linux.hp.com/~adb/cfq/cfq_dbase.png >> > > Thanks a lot, Alan! So the cfq hash does indeed improve things a little, > that's a shame. I guess I'll just reinstate the hash lookup. > > You're welcome Jens, but remember: It's one set of data; from one benchmark; on one architecture; on one platform...don't know if you should scrap the whole thing for that! :-) At the very least, I could look into trying it out on another architecture. Let me see what I can dig up... Alan - 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/