From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262914AbTJ3XAV (ORCPT ); Thu, 30 Oct 2003 18:00:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262941AbTJ3XAV (ORCPT ); Thu, 30 Oct 2003 18:00:21 -0500 Received: from zcars04f.nortelnetworks.com ([47.129.242.57]:10454 "EHLO zcars04f.nortelnetworks.com") by vger.kernel.org with ESMTP id S262914AbTJ3XAS (ORCPT ); Thu, 30 Oct 2003 18:00:18 -0500 Message-ID: <3FA195BD.2040701@nortelnetworks.com> Date: Thu, 30 Oct 2003 17:50:37 -0500 X-Sybari-Space: 00000000 00000000 00000000 00000000 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.8) Gecko/20020204 X-Accept-Language: en-us MIME-Version: 1.0 To: root@chaos.analogic.com Cc: George Anzinger , Peter Chubb , Stephen Hemminger , Gabriel Paubert , john stultz , Joe Korty , Linus Torvalds , lkml , Andrew Morton Subject: Re: gettimeofday resolution seriously degraded in test9 References: <20031027234447.GA7417@rudolph.ccur.com> <1067300966.1118.378.camel@cog.beaverton.ibm.com> <20031027171738.1f962565.shemminger@osdl.org> <20031028115558.GA20482@iram.es> <20031028102120.01987aa4.shemminger@osdl.org> <20031029100745.GA6674@iram.es> <20031029113850.047282c4.shemminger@osdl.org> <16288.17470.778408.883304@wombat.chubb.wattle.id.au> <3FA1838C.3060909@mvista.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 Richard B. Johnson wrote: > There isn't any magic that can solve this problem. It turns out > that with later Intel CPUs, one can get CPU-clock resolution > from rdtsc. However, this is hardware-specific. If somebody > modifies the gettimeofday() and the POSIX clock routines to > use rdtsc when available, a lot of problems will go away. Its not just x86. PowerPC has a similar call, so does MIPS, and I'm sure most other modern cpus do too. The only problem with this stuff is that they usually slow down when the cpu does, so laptops and other power-managed chips cause complexities. Chris -- Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: cfriesen@nortelnetworks.com