[ntp:questions] Time offset / Jitter under FreeBSD
Garrett Wollman
wollman at bimajority.org
Sun Dec 2 17:52:27 UTC 2007
In article <fitlnh$phn$1 at registered.motzarella.org>,
Bob <bobsjunkmail at bellsouth.net> wrote:
>I installed FreeBSD on a drive, and booted my windows machine from it. The
>FreeBSD port of ntpd shows a offsets in the 20-60 ms range. Issues with
>jitter, also.
How long did you leave it running? What drift value was reported?
My stratum-0, running FreeBSD 6.2, consistently reports offsets to
other stratum-0s within +/- 5 ms, and to its refclock within a couple
of microseconds with the nanokernel and kernel PPS. My stratum-1s,
likewise. These are all running the stock ntpd, which is 4.2.0-a.
$ ntpdc -c kerni ntp-0
pll offset: 1.314e-06 s
pll frequency: 68.119 ppm
maximum error: 0.012947 s
estimated error: 7e-06 s
status: 2107 pll ppsfreq ppstime ppssignal nano
pll time constant: 6
precision: 1e-09 s
frequency tolerance: 496 ppm
pps frequency: 68.119 ppm
pps stability: 0.022 ppm
pps jitter: 1.142e-06 s
calibration interval: 256 s
calibration cycles: 85694
jitter exceeded: 506860
stability exceeded: 0
calibration errors: 3
(The refclock here is an EndRun Technologies Praecis Ct.)
-GAWollman
--
Garrett A. Wollman | The real tragedy of human existence is not that we are
wollman at csail.mit.edu| nasty by nature, but that a cruel structural asymmetry
Opinions not those | grants to rare events of meanness such power to shape
of MIT or CSAIL. | our history. - S.J. Gould, Ten Thousand Acts of Kindness
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