[time-nuts] PPS jitter - Oncore VP w/NTP
timenuts at jcmco.com
Wed Jun 22 14:58:52 EDT 2005
Thanks for the quick replies, everybody! My comments below:
On Jun 22, 2005, at 2:39 PM, Poul-Henning Kamp wrote:
>>> pll offset: 1.106e-06 s
>>> pll frequency: 80.865 ppm
> This is not indicative of good hardware.
OK. What sort of numbers would I look for on a good system? An order
of magnitude difference from these?
> What does
> sysctl kern.timecounter
> say ?
% sysctl kern.timecounter
kern.timecounter.choice: TSC(800) i8254(0) dummy(-1000000)
> The jitter warning thing is very likely if you load on the
> machine which might disable interrupts for any amount of time.
It is a 200Mhz Pentium dedicated to the NTP role and doing nothing
other than ntpd and my login shells.
I will try some other motherboard/cpu combinations and compare the
results. Should I look at other platforms (Sun, etc) for better
Do you have some ntptime or kerninfo output from a "good" piece of
hardware that I can use as a goal? I'm mostly guessing at this point
what is good performance and what is bad but increasing error
counters most always seem bad. :-)
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