[ntp:questions] ATOM falseticker with flag3 enabled

David Lord snews at lordynet.org
Sun Apr 1 03:19:06 UTC 2012


A C wrote:
>> I'm not sure which value you are referring to. From the
>> "ntpq -p" billboard over a day, I see values of jitter
>> of the GPS as low as 0.002
> 
> Yes, it's that jitter however there's a minimum computed value below 
> which it never goes (varies per system).  On my system it used to be 
> computed at 0.061 (and all the configured clocks would report that as an 
> initial jitter until some data came in).  On the same system with 4.2.7 
> the value is now computed to be 0.122.
> 
> In any case apparently according to David Hart the code has indeed 
> changed so the computations are different.


Even after warm restarts I don't concern myself with  the
level of jitter until ntpd has had time to stabilise. After
an update to ntpd or kernel, and without a pps source, it
can be a day or more until a stable value for drift has
been established.

Has using 4.2.7 solved the problem with the type 20 and 22
drivers both being marked as falsetickers?

Were you able to determine a reasonable fudge time value
for the type 20 driver by using noselect for the type 20
driver and having several good internet sources?


David



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