From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on yquem.inria.fr X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=AWL autolearn=disabled version=3.1.3 X-Original-To: caml-list@yquem.inria.fr Delivered-To: caml-list@yquem.inria.fr Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by yquem.inria.fr (Postfix) with ESMTP id 141A5BB83 for ; Wed, 6 Sep 2006 17:16:07 +0200 (CEST) Received: from smtp1.adl2.internode.on.net (smtp1.adl2.internode.on.net [203.16.214.181]) by nez-perce.inria.fr (8.13.6/8.13.6) with ESMTP id k86FG5CT021748 for ; Wed, 6 Sep 2006 17:16:06 +0200 Received: from rosella (ppp14-47.lns2.syd7.internode.on.net [59.167.14.47]) by smtp1.adl2.internode.on.net (8.13.6/8.13.5) with ESMTP id k86FFQKQ018100; Thu, 7 Sep 2006 00:45:28 +0930 (CST) (envelope-from skaller@users.sourceforge.net) Subject: Re: [Caml-list] make[1]: warning: Clock skew detected. Your build may be incomplete. From: skaller To: Mattias Waldau Cc: caml-list@inria.fr In-Reply-To: <44FECEE6.50109@abc.se> References: <44FECEE6.50109@abc.se> Content-Type: text/plain Date: Thu, 07 Sep 2006 01:15:26 +1000 Message-Id: <1157555726.29547.15.camel@rosella.wigram> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit X-Miltered: at nez-perce with ID 44FEE635.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; mattias:01 waldau:01 ocaml:01 cygwin:01 ocaml:01 cmo':01 kernels:01 2006:98 sourceforge:01 wrote:01 caml-list:01 kernel:01 kernel:01 incomplete:03 fault:04 On Wed, 2006-09-06 at 15:36 +0200, Mattias Waldau wrote: > Hi, > > Got my new laptop with a Intel dual core. I get these funny messages. I > use Ocamlmakefile and ocaml under Cygwin on WinXP. > > Any ideas why? > > Anyone else getting these messages? > > make[1]: Warning: File `libraries/ocaml/date_helper.cmo' has > modification time 0.0041 s in the future Regularly? This is probably a kernel and/or motherboard fault. I had this problem with my dual core AMD64, only it wasn't wrong by 0.0041 s .. it was running almost double speed. The reason is related to the fact my board supports variable frequency CPU operation: when the load is low, it drops the CPU frequency, voltage, and fan speeds to conserve power and reduce noise. I had to disable this feature entirely. Both Windows and Linux seemed to suffer. On Linux the problem also went away using non-SMP kernel. Also, my Linux system (and probably Windows) uses network time server adjustment. Unfortunately, unlike old synchronisers, these modern ones just reset the clock, without worrying about screwing up file times (old ones would just speed up or slow down the clock marginally until the clock was right). I have no idea if this is your problem, but warn that time on some motherboard/SMP kernels is potentially bugged. It is possible the problem is software is using the CPU clock for timing, instead of the RTC, since RTC typically have only very coarse resolution. In that case, the software is using a clock which isn't regular. Check your bios, and try turning off variable frequency CPU operation, see if that fixes it? -- John Skaller Felix, successor to C++: http://felix.sf.net