Date: Mon, 22 Nov 2004 08:34:40 +0100 From: Christian Hiris <4711@chello.at> To: freebsd-questions@freebsd.org Cc: animecowboy@animecowboy.com Subject: Re: ntpd problem freebsd 5.3 [ and Re: I found your question about NTPd on Sep 27] Message-ID: <200411220834.56250.4711@chello.at> In-Reply-To: <200409250312.31974.4711@chello.at> References: <20040924202041.GM40647@therub.org> <200409250312.31974.4711@chello.at>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Monday 22 November 2004 03:40, animecowboy@animecowboy.com wrote: > I am having the same problem you mentioned here. > http://lists.freebsd.org/pipermail/freebsd-questions/2004-September/059279. > html > > I was wondering if you ever found out the cause and/or a way to correct the > problem. As this answer appears to be more complete, than my first one, I attached it to the original thread, just for the archives. I'm not a ntp specialist, so maybe there are some things that I misunderstood, but I think it's better than no answer. ;-) > Sep 23 17:13:41 panther ntpd[467]: kernel time sync enabled 2001 > Sep 23 21:29:44 panther ntpd[467]: kernel time sync enabled 6001 > Sep 23 21:46:48 panther ntpd[467]: kernel time sync enabled 2001 > Sep 24 01:11:39 panther ntpd[467]: kernel time sync enabled 6001 > Sep 24 01:45:47 panther ntpd[467]: kernel time sync enabled 2001 > Sep 24 02:19:59 panther ntpd[467]: kernel time sync enabled 6001 IMHO this isn't a problem - the messages are informational. ntpd just switches (kernel) clock discipline modes between PLL (Phase-Locked-Loop) and FLL (Frequency-Locked-Loop). I recently found a good documentation on ntpd PLL/FLL hybrid mode (including the differences between ntp v3/v4 PLL/FLL mode's handling): http://www.eecis.udel.edu/~mills/database/papers/allan.pdf I was pointed to the above link by http://www.freebsd.org/cgi/cvsweb.cgi/~checkout~/src/contrib/ntp/html/kern.html You also can find this document in /usr/src, if you have sources installed on your system. As I mentioned, there seems to be nothing wrong with messages 6001 and 2001. Kernel time discipline (and probably kernel time discipline messages) could be disabled via ntpdc control message's or ntpd config-file's "disable kernel" option. I think this also would disable nano-second clock-disciplining ability, so I would left it enabled. I never tried to disable kernel time discipline, so I can't imagine what would happen in real life ... http://www.freebsd.org/cgi/cvsweb.cgi/~checkout~/src/contrib/ntp/html/miscopt.html See also the option "tinker allan" option. This option allows you to change the seconds for minimum Allan intercept, which is a parameter of the PLL/FLL clock discipline algorithm. I left this at default value, too. http://www.freebsd.org/cgi/cvsweb.cgi/~checkout~/src/contrib/ntp/html/miscopt.html Loopfilter's implementation can be found at: http://www.freebsd.org/cgi/cvsweb.cgi/~checkout~/src/contrib/ntp/ntpd/ntp_loopfilter.c http://www.freebsd.org/cgi/cvsweb.cgi/~checkout~/src/sys/sys/timex.h Two simple examples of ntpd status decoding (see timex.h): Status message "time sync enabled 2001" tells us: STA_PLL 0x0001 [true] /* enable PLL updates (rw) */ STA_NANO 0x2000 [true] /* resolution (0 = us, 1 = ns) (ro) */ STA_MODE 0x4000 [false] /* mode (0 = PLL, 1 = FLL) (ro) * STA_CLK 0x8000 [false] /* clock source (0 = A, 1 = B) (ro) */ - ------------------------------------------------------------------ 0x2001 PLL upd. on, Resolution=ns, mode=PLL, clock-src=A Status message "time sync enabled 6001" tells us: STA_PLL 0x0001 [true] /* enable PLL updates (rw) */ STA_NANO 0x2000 [true] /* resolution (0 = us, 1 = ns) (ro) */ STA_MODE 0x4000 [true] /* mode (0 = PLL, 1 = FLL) (ro) * STA_CLK 0x8000 [false] /* clock source (0 = A, 1 = B) (ro) */ - ----------------------------------------------------------------- 0x6001 PLL upd. on, Resolution=ns, mode=FLL, clock-src=A Cheers, ch - -- Christian Hiris <4711@chello.at> | OpenPGP KeyID 0x3BCA53BE OpenPGP-Key at hkp://wwwkeys.eu.pgp.net and http://pgp.mit.edu -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFBoZag09WjGjvKU74RAoveAJ9vbuBz+wDK24VZL9+KSKL4GDvMcgCbBvzm 4Yd/BHzqkNicKibb+rlDky0= =SH5B -----END PGP SIGNATURE-----
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