From owner-freebsd-current Mon Jul 15 08:38:41 1996 Return-Path: owner-current Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id IAA18031 for current-outgoing; Mon, 15 Jul 1996 08:38:41 -0700 (PDT) Received: from halloran-eldar.lcs.mit.edu (halloran-eldar.lcs.mit.edu [18.26.0.159]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id IAA18024 for ; Mon, 15 Jul 1996 08:38:32 -0700 (PDT) Received: by halloran-eldar.lcs.mit.edu; (5.65/1.1.8.2/19Aug95-0530PM) id AA11824; Mon, 15 Jul 1996 11:38:02 -0400 Date: Mon, 15 Jul 1996 11:38:02 -0400 From: Garrett Wollman Message-Id: <9607151538.AA11824@halloran-eldar.lcs.mit.edu> To: sthaug@nethelp.no Cc: bde@zeta.org.au, current@freebsd.org Subject: xntpd stepping clock backwards? (was: Re: NFSv3 fixes for review) In-Reply-To: <20426.837433714@verdi.nethelp.no> References: <199607140805.SAA20603@godzilla.zeta.org.au> <20426.837433714@verdi.nethelp.no> Sender: owner-current@freebsd.org X-Loop: FreeBSD.org Precedence: bulk <> xntpd only does tiny adjustments which can't possibly make the clock >> go backwards. OTOH, ntpdate or ordinary `date' can set the clock back >> by years. > Then why does my syslog show the following? It sure looks to me like xntpd > sometimes steps the clock backwards. This is on 2.2-960612-SNAP. > Jul 7 14:57:36 verdi xntpd[84]: time reset (step) 0.151413 s > Jul 7 21:34:16 verdi xntpd[84]: time reset (step) 0.133152 s > Jul 9 17:32:48 verdi xntpd[84]: time reset (step) -0.135963 s > Jul 9 17:37:49 verdi xntpd[84]: time reset (step) 0.133687 s xntpd will fall back to stepping the clock if the difference is too great for adjtime(2) or adjtime doesn't appear to be working (which means the same thing). In your case, it looks very much like your machine is clock-hopping, a problem to which xntpd is extremely prone if you have lots of clocks and bad network connections to them. You can probably solve this problem by deleting the extra clocks from your ntp.conf file, or by choosing ones that are closer to you. -GAWollman -- Garrett A. Wollman | Shashish is simple, it's discreet, it's brief. ... wollman@lcs.mit.edu | Shashish is the bonding of hearts in spite of distance. Opinions not those of| It is a bond more powerful than absence. We like people MIT, LCS, ANA, or NSA| who like Shashish. - Claude McKenzie + Florent Vollant