From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262283AbVGXBHx (ORCPT ); Sat, 23 Jul 2005 21:07:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262284AbVGXBHx (ORCPT ); Sat, 23 Jul 2005 21:07:53 -0400 Received: from outpost.ds9a.nl ([213.244.168.210]:49378 "EHLO outpost.ds9a.nl") by vger.kernel.org with ESMTP id S262283AbVGXBHb (ORCPT ); Sat, 23 Jul 2005 21:07:31 -0400 Date: Sun, 24 Jul 2005 03:07:30 +0200 From: bert hubert To: Paul Jackson , rostedt@goodmis.org, relayfs-devel@lists.sourceforge.net, richardj_moore@uk.ibm.com, varap@us.ibm.com, karim@opersys.com, linux-kernel@vger.kernel.org, zanussi@us.ibm.com Subject: diskstat 0.1: simple tool to study io patterns via relayfs Message-ID: <20050724010730.GA22104@outpost.ds9a.nl> Mail-Followup-To: bert hubert , Paul Jackson , rostedt@goodmis.org, relayfs-devel@lists.sourceforge.net, richardj_moore@uk.ibm.com, varap@us.ibm.com, karim@opersys.com, linux-kernel@vger.kernel.org, zanussi@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org It is with distinct lack of pride that I release version 0.1 of diskstat 'Geeks in Black Thorn', a tool that allows you to generate the kinds of graphs as presented in my OLS talk 'On faster application startup times: Cache stuffing, seek profiling, adaptive preloading'. The lack of pride is because this release is more a promise of what is to come than how things should be. The presentation, paper, and software can be found on http://ds9a.nl/diskstat and http://ds9a.nl/diskstat/diskstat-0.1.tar.gz >>From the README: The quality of this code is abysmal, for which I squarely blame the fun people at OLS who've been keeping me from my code! (...) The next version will be based on k/jprobes, and will make better use of relayfs features. This also means you won't have to patch your kernel anymore, as long as you compiled with kprobes support. Sample command lines: # mkdir /relay # mount -t relayfs none /relay # ./dumpdiskstat /relay/diskstat0 > dump This will output something like: I think we skipped at 90867, ret=0 I think we hit end at 143016, ret=-1 I think we hit the break again 90867, ret=0 Process the stats. $ ./dswalk < dump It will print out huge latencies encountered: > Large latency 163.352 on line 14146 Total read started: 33888768, total ended: 33888768 Total write started: 1372160, total ended: 1372160 Waiting time: 10.695 seconds Make pretty plots gnuplot plot 'startplaces.dat', 'headplaces.dat' plot 'inflight.dat' Continue reading on http://ds9a.nl/diskstat/README -- http://www.PowerDNS.com Open source, database driven DNS Software http://netherlabs.nl Open and Closed source services