Date: Wed, 29 Dec 1999 06:39:27 -0800 (PST) From: Poul-Henning Kamp <phk@FreeBSD.org> To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/kern kern_ntptime.c Message-ID: <199912291439.GAA19053@freefall.freebsd.org>
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phk 1999/12/29 06:39:27 PST
Modified files:
sys/kern kern_ntptime.c
Log:
Don't use time_offset as a leaky bucket variable in hardpps(), this
resulted in vastly optimistic offset values reported to userland
(typically a factor 40+ too small). Apart from that, the code had
two sign-bugs.
Apply the hardpps() phase with the right sign with a simply
scaling by integration interval. (This may be too stiff at
long integration intervals, see below).
Allow pps_shiftmax to be reduced again.
Before this, the phase lock in hardpps() were broken, but due to
two bugs mostly cancelling out, it would end up basically working
with a large stochastic component. Now it behaves as one would
expect: smooth and quiet.
It seems that pps_shiftmax above 7..9 somewhere makes the phaselock
too weak to hold onto random walk phase errors from a HP-105 OCXO,
which basically means that it is too weak for real-life use with
such integration times. This is yet to be resolved.
Submitted to: Prof. Dave "NTP" Mills.
Tested by: Terje Mathisen <Terje.Mathisen@hda.hydro.com>
Revision Changes Path
1.30 +18 -15 src/sys/kern/kern_ntptime.c
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