From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 23 May 2002 10:05:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 23 May 2002 10:05:38 -0400 Received: from eventhorizon.antefacto.net ([193.120.245.3]:50914 "EHLO eventhorizon.antefacto.net") by vger.kernel.org with ESMTP id ; Thu, 23 May 2002 10:05:37 -0400 Message-ID: <3CECF70C.1060208@antefacto.com> Date: Thu, 23 May 2002 15:05:00 +0100 From: Padraig Brady User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0rc2) Gecko/20020510 X-Accept-Language: en-us, en MIME-Version: 1.0 To: will fitzgerald CC: linux-kernel@vger.kernel.org Subject: Re: Question:kernel profiling and readprofile In-Reply-To: <1864B06FE5DED9149A7F262BF4C5E5DE@william.fitzgerald6.beer.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org will fitzgerald wrote: > hi all, > > i stumbled accross a command called readprofile by accident and found > that by appening the line append="profile=2" to the lilo.conf file > and using thread profile command you can get statistics on functions > that spend a certain amount of time doing a job. > > i done some searching on this and can't find anything other than a > man page on readprofile. > > can anyone tell me what does the line append="profile=2" actually do > apart from creating the file profile in the proc directory, what is > the 2 for in this line? The level. see linux/Documentation/kernel-parameters.txt Also worth looking at is http://oss.sgi.com/projects/kernprof/ > next is this an accurate way to measure heady traffic load through > say a linux router? I presume you don't want to actually measure traffic throughput as there are obviously other ways to do this. > will it highlight all functions say for example > ip_forward, dev_queue_xmit etc etc that are being opverloaded due to > huge traffic loads being passed through the router. ie will it spot > bottlenecks with good accuracy? yes that's the idea. > any feedback is welcomed, > regards will. Also note CONFIG_NET_PROFILE=Y which writes more network specific profile data to /proc/net/profile, which you'll have to figure out how to parse. Also I think it was reported that there were some problems with profiling (missing symbols) around 2.5.8? I don't know whether it's been fixed. Also I don't think you can profile modules, but there was a patch... http://marc.theaimsgroup.com/?l=linux-kernel&m=101663078100596&w=2 Padraig.