[ntp:questions] NTPD_USE_INTERP_DANGEROUS was ARRGH!!! I woke up to a 50 SECOND clock error.
Ron Frazier (NTP)
timekeepingntplist at c3energy.com
Sun Mar 18 14:17:28 UTC 2012
I'm forking the subject line, which didn't really seem relevant any more.
On 3/18/2012 7:01 AM, David J Taylor wrote:
> "Ron Frazier (NTP)" <timekeepingntplist at c3energy.com> wrote in message
> news:4F65006D.4090205 at c3energy.com...
>> Come to think of it, my comment about the polling interval not
>> increasing may only apply to a local refclock, not a local server.
> You may be right - all the servers on this test system are Internet
>> Can you elaborate more about what NTPD_USE_INTERP_DANGEROUS does?
> Overnight results are here:
> As you can see, jitter is under a millisecond, with the local
> (noselect) server showing about half a millisecond of jitter, and the
> Internet servers between about 3 and just over 6 milliseconds.
From my point of view, those look pretty good. Those peerstats graphs
come in pretty handy.
> NTPD_USE_INTERP_DANGEROUS if set, forces interpolation on Windows.
> With Windows XP or earlier, Interpolation works well, but not on Vista
> or later, so under certain conditions, NTP disables interpolation as
> mentioned here:
> You can enable interpolation, and you may get better results. If not,
> jitters will have a floor of about 0.977 milliseconds.
What's the dangerous part? Are we just talking lots of CPU churning?
If so, can I just shut down NTP and tweak it?
(PS - If you email me and don't get a quick response, don't be concerned.
I get about 300 emails per day from alternate energy mailing lists and
such. I don't always see new messages very quickly. If you need a
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timekeepingdude AT c3energy.com
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