Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932324AbVLDTzE (ORCPT ); Sun, 4 Dec 2005 14:55:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932329AbVLDTzE (ORCPT ); Sun, 4 Dec 2005 14:55:04 -0500 Received: from omx3-ext.sgi.com ([192.48.171.20]:64426 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S932324AbVLDTzD (ORCPT ); Sun, 4 Dec 2005 14:55:03 -0500 Date: Sun, 4 Dec 2005 11:54:46 -0800 From: Paul Jackson To: Marcel Zalmanovici Cc: kernel@kolivas.org, linux-kernel@vger.kernel.org, mulix@mulix.org Subject: Re: Inconsistent timing results of multithreaded program on an SMP machine. Message-Id: <20051204115446.0a026538.pj@sgi.com> In-Reply-To: References: <20051124044313.6259092d.pj@sgi.com> Organization: SGI X-Mailer: Sylpheed version 2.1.7 (GTK+ 2.4.9; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 891 Lines: 21 Marcel wrote: > I think that the conclusion from this test is that the write-back algorithm > might be responsible for the oscillating results. Well ... if you suspect your storage/hardware, then try a different file system, such as network files or /dev/ramdisk. It's a few seconds worth of difference you're dealing with, so try playing around with printf's in the user code and printk's in the kernel at key points in the sequence of events, so you can see what happens when. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401 - 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/