From owner-freebsd-current Wed Dec 27 13:03:25 1995 Return-Path: owner-current Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id NAA16620 for current-outgoing; Wed, 27 Dec 1995 13:03:25 -0800 (PST) Received: from halloran-eldar.lcs.mit.edu (halloran-eldar.lcs.mit.edu [18.26.0.159]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id NAA16610 for ; Wed, 27 Dec 1995 13:03:20 -0800 (PST) Received: by halloran-eldar.lcs.mit.edu; (5.65/1.1.8.2/19Aug95-0530PM) id AA17279; Wed, 27 Dec 1995 16:03:05 -0500 Date: Wed, 27 Dec 1995 16:03:05 -0500 From: "Garrett A. Wollman" Message-Id: <9512272103.AA17279@halloran-eldar.lcs.mit.edu> To: peter@haywire.dialix.com (Peter Wemm) Cc: freebsd-current@freebsd.org Subject: Re: Tick, tock, adjust the clock In-Reply-To: <4bqdc4$8h2$1@haywire.DIALix.COM> References: <199512261708.LAA14134@miller.cs.uwm.edu> <4bqdc4$8h2$1@haywire.DIALix.COM> Sender: owner-current@freebsd.org Precedence: bulk < I've had the same problem for quite some time.. On all the > FreeBSD machines I have access to, the xntpd oscilates very very badly > (like you've shown) and eventually logs "not logging any more time > steps" or something like that. I'm curious to know whether the clock speed is correctly diagnosed on these machines... This sounds like the sort of thing I would expect to happen if the clock-speed-diagnosis code doesn't come up with an answer that's reasonably close. My 60-MHz machine is diagnosed as 59.99-MHz, and xntpd reports its frequency error as about 7.6 seconds per day. You might try making i586_ctr_rate tunable via sysctl(8), and fiddling the value a little bit to see if you can come up with something more correct. That would be a very good feature to have, and I may get around to adding it sometime soon since PHK's sysctl is able to deal with variables that are only conditionally defined in a reasonable way. (It's a fixed-point number with I586_CTR_RATE_SHIFT bits of fractional precision.) > The really depressing part, is the SVR4 machines (you know, the ones > with the horrible 10ms clock resolution) sitting right next to the > FreeBSD machines with their super-high-res clocks are locking right in > and staying very stable (xntpd getting to 1024 poll and very low > dispersion), while the FreeBSD machines are constantly wobbling all > over the place. :-( My machine looks like this: remote refid st t when poll reach delay offset disp ============================================================================== +catfish.lcs.mit rackety.udel.ed 2 u 294 1024 357 2.24 5.002 1.25 +amsterdam.lcs.m ncar.ucar.edu 2 u 540 1024 377 2.09 5.686 4.17 eiffel.lcs.mit. tock.usno.navy. 2 - 38m 512 0 2.93 3.993 16000.0 pepper.lcs.mit. catfish.lcs.mit 3 u 654 1024 377 4.50 5.002 1.46 *pooch.osf.org .WWV. 1 u 69 1024 377 10.24 4.069 4.06 halloran-eldar. catfish.lcs.mit 3 u 815 512 324 3.97 6.322 4.65 hergotha.lcs.mi catfish.lcs.mit 3 u 417 1024 252 0.87 4.868 7.98 NTP.MCAST.NET 0.0.0.0 16 u - 64 0 0.00 0.000 16000.0 -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