From owner-freebsd-questions@FreeBSD.ORG Thu Mar 13 19:01:33 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id A394DF44 for ; Thu, 13 Mar 2014 19:01:33 +0000 (UTC) Received: from st11p05mm-asmtp002.mac.com (st11p05mm-asmtp002.mac.com [17.172.108.250]) by mx1.freebsd.org (Postfix) with ESMTP id 78C80FB for ; Thu, 13 Mar 2014 19:01:33 +0000 (UTC) Received: from [17.149.233.5] (unknown [17.149.233.5]) by st11p05mm-asmtp002.mac.com (Oracle Communications Messaging Server 7u4-27.08(7.0.4.27.7) 64bit (built Aug 22 2013)) with ESMTPSA id <0N2D005YDZE2KQ40@st11p05mm-asmtp002.mac.com> for freebsd-questions@freebsd.org; Thu, 13 Mar 2014 18:01:16 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.11.87,1.0.14,0.0.0000 definitions=2014-03-13_07:2014-03-13,2014-03-13,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=1 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1402240000 definitions=main-1403130096 Content-type: text/plain; charset=us-ascii MIME-version: 1.0 (Mac OS X Mail 7.2 \(1874\)) Subject: Re: ntp frequent time resets - battery dead? From: Charles Swiger In-reply-to: <201403121926.s2CJQXbQ078112@mech-cluster241.men.bris.ac.uk> Date: Thu, 13 Mar 2014 11:01:14 -0700 Content-transfer-encoding: quoted-printable Message-id: References: <201403121926.s2CJQXbQ078112@mech-cluster241.men.bris.ac.uk> To: mexas@bris.ac.uk X-Mailer: Apple Mail (2.1874) Cc: FreeBSD - X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 13 Mar 2014 19:01:33 -0000 Hi-- On Mar 12, 2014, at 12:26 PM, Anton Shterenlikht = wrote: >> Yes, it looks to be about ~1 second per hour. That's 1:1000 ratio, >> which is getting close to the typical kernel limit on adjtime(). >>=20 >> Tweaking the step threshold might help. Or look into tickadj / = ntptime. >=20 > Sorry, I don't understand this. > Please elaborate. OK. ntpd has two ways of adjusting the clock; either it gradually slews = the time via adjtime() or it jumps the clock via settimeofday() and logs the = "time reset" lines you've noted. Which method is chosen is based upon the step threshold, which defaults = to 128 ms (aka .128 seconds). Increasing the step threshold will have ntpd try to = slew the clock even for the larger corrections your case seems to need. Regards, --=20 -Chuck