Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751818AbWJADmT (ORCPT ); Sat, 30 Sep 2006 23:42:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751824AbWJADmT (ORCPT ); Sat, 30 Sep 2006 23:42:19 -0400 Received: from tomts40-srv.bellnexxia.net ([209.226.175.97]:18650 "EHLO tomts40-srv.bellnexxia.net") by vger.kernel.org with ESMTP id S1751818AbWJADmS (ORCPT ); Sat, 30 Sep 2006 23:42:18 -0400 Date: Sat, 30 Sep 2006 23:42:12 -0400 From: Mathieu Desnoyers To: Nicholas Miell Cc: Martin Bligh , "Frank Ch. Eigler" , Masami Hiramatsu , prasanna@in.ibm.com, Andrew Morton , Ingo Molnar , Paul Mundt , linux-kernel , Jes Sorensen , Tom Zanussi , Richard J Moore , Michel Dagenais , Christoph Hellwig , Greg Kroah-Hartman , Thomas Gleixner , William Cohen , ltt-dev@shafik.org, systemtap@sources.redhat.com, Alan Cox , Jeremy Fitzhardinge , Karim Yaghmour , Pavel Machek , Joe Perches , "Randy.Dunlap" , "Jose R. Santos" Subject: Re: Performance analysis of Linux Kernel Markers 0.20 for 2.6.17 Message-ID: <20061001034212.GB13527@Krystal> References: <20060930180157.GA25761@Krystal> <1159642933.2355.1.camel@entropy> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <1159642933.2355.1.camel@entropy> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.4.32-grsec (i686) X-Uptime: 23:31:55 up 39 days, 40 min, 1 user, load average: 0.24, 0.21, 0.20 User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2240 Lines: 70 * Nicholas Miell (nmiell@comcast.net) wrote: > On Sat, 2006-09-30 at 14:01 -0400, Mathieu Desnoyers wrote: > > Hi, > > > > Following the huge discussion thread about tracing/static vs dynamic > > instrumentation/markers, a consensus seems to emerge about the need for a > > marker system in the Linux kernel. The main issues this mechanism addresses are: > > > > - Identify code important to runtime data collection/analysis tools in tree so > > that it follows the code changes naturally. > > - Be visually appealing to kernel developers. > > - Have a very low impact on the system performance. > > - Integrate in the standard kernel infrastructure : use C and loadable modules. > > > > The time has come for some performance measurements of the Linux Kernel Markers, > > which follows. I attach a PDF with tables and charts which condense these > > results. > > Has anyone done any performance measurements with the "regular function > call replaced by a NOP" type of marker? > Here it is (on the same setup as the other tests : Pentium 4, 3 GHz) : * Execute an empty loop - Without marker NR_LOOPS : 10000000 time delta (cycles): 15026497 cycles per loop : 1.50 - With 5 NOPs NR_LOOPS : 100000 time delta (cycles): 300157 cycles per loop : 3.00 added cycles per loop for nops : 3.00-1.50 = 1.50 * Execute a loop of memcpy 4096 bytes - Without marker NR_LOOPS : 10000 time delta (cycles): 12981555 cycles per loop : 1298.16 - With 5 NOPs NR_LOOPS : 10000 time delta (cycles): 12983925 cycles per loop : 1298.39 added cycles per loop for nops : 0.23 If we compare this approach to the jump-over-call markers (in cycles per loop) : NOPs Jump over call generic Jump over call optimized empty loop 1.50 1.17 2.50 memcpy 0.23 2.12 0.07 Mathieu OpenPGP public key: http://krystal.dyndns.org:8080/key/compudj.gpg Key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - 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/