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, 14 Nov 2002 12:54:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 14 Nov 2002 12:54:50 -0500 Received: from [195.223.140.107] ([195.223.140.107]:31121 "EHLO athlon.random") by vger.kernel.org with ESMTP id ; Thu, 14 Nov 2002 12:54:48 -0500 Date: Thu, 14 Nov 2002 19:01:17 +0100 From: Andrea Arcangeli To: Andi Kleen Cc: John Alvord , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: module mess in -CURRENT Message-ID: <20021114180117.GM31697@dualathlon.random> References: <20021114184049.A28183@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20021114184049.A28183@wotan.suse.de> User-Agent: Mutt/1.3.27i X-GPG-Key: 1024D/68B9CB43 X-PGP-Key: 1024R/CB4660B9 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 14, 2002 at 06:40:49PM +0100, Andi Kleen wrote: > > Owens' kbuild-2.5 handled it a different way and didn't need exact > > timings. That is especially important since nanosecond time accuracy is > > You may not believe it, but there are projects other than the kernel > that do use make too. > > > impossible if you are handling a collection of machines doing the > > work. NTP is accurate, but not that accurate. > > The patch does not actually implement nanosecond resolution, but > jiffies resolution (1ms on 2.5), which is easily reachable with NTP. 1msec still leave a reasonable window open IMHO. this problem would need sequence numbers updated atomically to be solved correctly without regard to the timing that may vary depending on the hardware IMHO (so that it could still work on a 1Thz cpu even if it's not a pratical matter for at least this decade). Andrea