From owner-freebsd-questions@FreeBSD.ORG Thu May 15 19:30:30 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 19E1F1065683 for ; Thu, 15 May 2008 19:30:30 +0000 (UTC) (envelope-from rvm@CBORD.com) Received: from smssmtp.cbord.com (mx1.cbord.com [24.39.174.11]) by mx1.freebsd.org (Postfix) with ESMTP id CA8858FC25 for ; Thu, 15 May 2008 19:30:29 +0000 (UTC) (envelope-from rvm@CBORD.com) X-AuditID: ac1f0165-00000db4000002f4-be-482c8f1e66cc Received: from Email.cbord.com ([10.1.1.100]) by smssmtp.cbord.com with Microsoft SMTPSVC(6.0.3790.1830); Thu, 15 May 2008 15:29:34 -0400 X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Date: Thu, 15 May 2008 15:28:36 -0400 Message-ID: In-Reply-To: <20080515185758.GA12709@ikarus.thalreit> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: time drift Thread-Index: Aci2v1FqWOqZ4EpRSFmF9MMjCO+YtQAAZPBA References: <20080515185758.GA12709@ikarus.thalreit> From: "Bob McConnell" To: X-Brightmail-Tracker: AAAAAA== 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 19:30:30 -0000 -----Original Message----- From: owner-freebsd-questions@freebsd.org [mailto:owner-freebsd-questions@freebsd.org] On Behalf Of Volker Jahns Sent: Thursday, May 15, 2008 2:58 PM To: freebsd-questions@freebsd.org Cc: volker@thalreit.de Subject: time drift 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 FreeBSD 7.0 on an otherwise almost identical system has a time drift of a few millisecs every half hour. 15 May 10:35:00 ntpdate[7999]: adjust time server 192.53.103.108 offset 0.009963 sec 15 May 10:35:51 ntpdate[8007]: adjust time server 192.53.103.108 offset -0.004890 sec 15 May 10:50:00 ntpdate[8042]: adjust time server 192.53.103.108 offset 0.010734 sec 15 May 11:05:00 ntpdate[8088]: adjust time server 192.53.103.108 offset 0.004523 sec 15 May 11:20:01 ntpdate[8114]: adjust time server 192.53.103.108 offset 0.005800 sec The 6.2 system is a production system, has a uptime of almost 300 days and I don't want=20 to experiment a lot with acpi, battery or so.=20 What would be your suspicion on the large time drift of the FreeBSD 6.2 system? --=20 Volker Jahns, volker@thalreit.de ---------------------------------- It loses 28 seconds per hour 28/3600 =3D 0.0077777777777777777, or less than 1 percent slow. That is well within normal parts tolerances for a new computer, and the drift usually gets worse as the hardware ages. I believe you are also looking at the software clock, not the hardware clock. The latter may be a little more accurate, since the former may be slowed down by interrupts and software that disables them. Install ntpd and let it adjust the clock for you. Bob McConnell