Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753130AbZIRHZB (ORCPT ); Fri, 18 Sep 2009 03:25:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751288AbZIRHZA (ORCPT ); Fri, 18 Sep 2009 03:25:00 -0400 Received: from james.oetiker.ch ([213.144.138.195]:35117 "EHLO james.oetiker.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751220AbZIRHZA (ORCPT ); Fri, 18 Sep 2009 03:25:00 -0400 Date: Fri, 18 Sep 2009 09:24:59 +0200 (CEST) From: Tobias Oetiker To: linux-kernel@vger.kernel.org Subject: announce: fsopbench - filesystem operations benchmark Message-ID: User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2627 Lines: 61 Hi, As explained in a mail earlier this week I am in the process of optimizing interactive performance for a file-server under high write load. To help in this venture, I have written a benchmark for measuring the response time of filesystem operations. http://oss.oetiker.ch/optools/wiki/fsopbench The benchmark program is able to generate a artificial filesystem tree with a file size distribution similar to a home directory tree. To simulate the write load it can fork of several writer processes in the background. It shows similar results on all configurations I have tested. In the example below you see: * lstat: 10 times slower * reading the first byte of a file: 80 times slower * reading a directory entry: 16 times slower * read rate: 40 times lower On top of that the standard deviation of the measurments goes way up with extreme maximal wait times in the 1 second range. Some numbers form 2.6.31 with cfq on an Areca HW Raid6 (the results from single disks are similar but less pronounced) Reading Only - Mode 30s Interval ----------------------------------------------------------------- A read dir cnt 29512 min 0.001 ms max 14.273 ms mean 0.081 ms stdev 0.694 B lstat file cnt 27797 min 0.006 ms max 12.471 ms mean 0.071 ms stdev 0.571 C open file cnt 22644 min 0.013 ms max 0.390 ms mean 0.019 ms stdev 0.012 D rd 1st byte cnt 22644 min 0.114 ms max 23.614 ms mean 0.591 ms stdev 1.464 E read rate 71.492 MB/s In-Competition with 6 Writers - Mode 30s Interval ----------------------------------------------------------------- A read dir cnt 625 min 0.001 ms max 167.049 ms mean 1.355 ms stdev 11.462 B lstat file cnt 589 min 0.006 ms max 182.580 ms mean 0.503 ms stdev 7.747 C open file cnt 479 min 0.014 ms max 0.134 ms mean 0.021 ms stdev 0.011 D rd 1st byte cnt 479 min 0.180 ms max 1114.885 ms mean 40.708 ms stdev 143.536 E read rate 1.566 MB/s I have been testing some patches provided by Corrado Zoccolo but no solution has been found yet. cheers tobi -- Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland http://it.oetiker.ch tobi@oetiker.ch ++41 62 775 9902 / sb: -9900 -- 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/