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Re: [gpsd-dev] Clarifications needed for the time-service HOWTO


From: Hal Murray
Subject: Re: [gpsd-dev] Clarifications needed for the time-service HOWTO
Date: Thu, 24 Oct 2013 11:27:36 -0700

>> ntpd looks at it only once per second anyway.
> No, nptd looks at it once per minpoll.

Depends upon what you mean by "look".

I've said this before.  Looks like I'm not the only one suffering from email 
overload.

ntpd has a 2 step process.  It looks at the SHM slot every second.  If there 
is a sample available, it gets copied to a buffer/fifo.  Every polling 
interval, ntpd takes the whole buffer, discards outliers, averages the rest, 
then feeds that answer to the main timekeeping logic.

Note that you said "minpoll".  The polling interval can be anywhere between 
minpoll and maxpoll.  (There is a global min/maxpoll as well as one for each 
refclock instance.  I'd have to check the details to see how they interact.)


-- 
These are my opinions.  I hate spam.






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