From owner-freebsd-questions@FreeBSD.ORG Thu May 15 20:37:14 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1550C1065670 for ; Thu, 15 May 2008 20:37:14 +0000 (UTC) (envelope-from volker@thalreit.de) Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.187]) by mx1.freebsd.org (Postfix) with ESMTP id A1D508FC1D for ; Thu, 15 May 2008 20:37:13 +0000 (UTC) (envelope-from volker@thalreit.de) Received: from thalreit.de (p5496D19C.dip.t-dialin.net [84.150.209.156]) by mrelayeu.kundenserver.de (node=mrelayeu6) with ESMTP (Nemesis) id 0ML29c-1JwkCO1KFB-0004xA; Thu, 15 May 2008 22:37:12 +0200 Received: from localhost ([127.0.0.1] helo=ikarus.thalreit) by thalreit.de with esmtp (Exim 4.63 (FreeBSD)) (envelope-from ) id 1JwkCe-0003kR-Vb; Thu, 15 May 2008 22:37:29 +0200 Received: (from volker@localhost) by ikarus.thalreit (8.13.6/8.13.6/Submit) id m4FKbSTD014410; Thu, 15 May 2008 22:37:28 +0200 (CEST) (envelope-from volker) Date: Thu, 15 May 2008 22:37:28 +0200 From: Volker Jahns To: Volker Jahns Message-ID: <20080515203728.GA14284@ikarus.thalreit> References: <20080515185758.GA12709@ikarus.thalreit> <597571FB-C72D-4603-B379-A59A435843BE@mac.com> <20080515195302.GA13531@ikarus.thalreit> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080515195302.GA13531@ikarus.thalreit> User-Agent: Mutt/1.4.2.3i X-Provags-ID: V01U2FsdGVkX1/lXCA6kRlll0nW8RxQdSoxrQm56UvD7AaLPXJ NEd5Y5Q+VXk6nwFyaT+8Se3wflmJuaB7Wie7lGF8u2vtYml8uR eh34uEpX2z8HPY3iUmWiA== Cc: freebsd-questions@freebsd.org Subject: Re: time drift X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 May 2008 20:37:14 -0000 On Thu, May 15, 2008 at 09:53:02PM +0200, Volker Jahns wrote: > On Thu, May 15, 2008 at 12:18:57PM -0700, Chuck Swiger wrote: > > On May 15, 2008, at 11:57 AM, Volker Jahns wrote: > > >FreeBSD 6.2 running on X86 hardware (FSC) shows a remarkable time > > >drift > > > > > >running ntpdate every half hour shows that the system looses about > > >10-14 sec each time. > > >15 May 10:06:48 ntpdate[7200]: step time server 192.53.103.108 > > >offset -13.799602 sec > > >15 May 10:36:48 ntpdate[7515]: step time server 192.53.103.108 > > >offset -12.813941 sec > > >15 May 11:06:48 ntpdate[7879]: step time server 192.53.103.108 > > >offset -13.651921 sec > > >15 May 11:36:50 ntpdate[8079]: step time server 192.53.103.108 > > >offset -11.109298 sec > > >15 May 12:06:50 ntpdate[8289]: step time server 192.53.103.108 > > >offset -11.836499 sec > > > > You should also take a look at the output of "sysctl > > kern.timecounter", and possibly switch to a different mechanism, if > > the existing choice doesn't work out well for your machine... > Thanks for the hint. A few years ago a time drift problem had been observed by a German freebsd user (http://www.freebsd.de/rachive/de-bsd-questions.200304/0643.html). Time drift 15 sec every half hour, ntpd dies away running on his machine. Setting kern.timecounter.hardware to TSC had been recommended as a solution. -- Volker Jahns, volker@thalreit.de