From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261253AbVGGJyf (ORCPT ); Thu, 7 Jul 2005 05:54:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261265AbVGGJyf (ORCPT ); Thu, 7 Jul 2005 05:54:35 -0400 Received: from mf01.sitadelle.com ([212.94.174.68]:7902 "EHLO smtp.cegetel.net") by vger.kernel.org with ESMTP id S261253AbVGGJye (ORCPT ); Thu, 7 Jul 2005 05:54:34 -0400 Message-ID: <42CCFBA1.1090807@lifl.fr> Date: Thu, 07 Jul 2005 11:53:37 +0200 From: Eric Piel Organization: LIFL User-Agent: Mozilla Thunderbird 1.0.2-3mdk (X11/20050322) X-Accept-Language: en, fr, ja, es MIME-Version: 1.0 To: Sheo Shanker Prasad Cc: "David S. Miller" , linux-kernel@vger.kernel.org Subject: Re: Disturbing wide variation in execution time References: <200507062344.53615.ssp@creativeresearch.org> <20050707.001038.71088533.davem@davemloft.net> <200507070103.25563.ssp@creativeresearch.org> In-Reply-To: <200507070103.25563.ssp@creativeresearch.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org (please do not top-post) 07.07.2005 10:03, Sheo Shanker Prasad wrote/a écrit: > Dear David, > > The program is an atmospheric chemistry-transport modeling code that computes > the distributions of atmospheric species (e.g., ozone) as a function of > latitude and altitude and how that changes with time. Well, to let us examine your problem, you need to describe what *technicaly* does your program. ie: lots of disk access, lots of networks acces, lots of CPU access, allocate huge memory... in particular, is it CPU bound or I/O bound? You should also mention how tasks/thread is your program composed of. It's good to describe your hardware: cluster of NUMA computers or just one x86? How much memory, what kind of network, how many hard disks, which exact version of the kernel.... Cherry on the top, you could include a *small* program which exhibit the same problem. > > Thanks for taking time to think about my problem. I greatly appreciate it. > To answer briefly your question, _in general_ a program which takes more than a few seconds to execute should take roughly the same time to execute all the times. Eric