[ntp:questions] how long does it take ntpd to sync up

David J Taylor david-taylor at blueyonder.co.uk.invalid
Sun Aug 28 05:42:08 UTC 2011

"unruh" <unruh at wormhole.physics.ubc.ca> wrote in message 
news:slrnj5imoe.2fi.unruh at wormhole.physics.ubc.ca...
> See the last two graphs on www.theory.physics.ubc.ca/chrony/chrony.html
> which are the response of ntp to a rate change from about215PPM to
> 168PPM The "halving time" for the offset is about .04 days, which is
> about 1 hr. Thus it depends on how far off you clock is. Also this graph
> is for the poll interval of 16 sec. ( a gps receiver) For longer poll
> intervals the time will be proportionately longer.


The bottom of that page mentions ntp versions 4.2.0 and 4.2.4, which are 
not current.

In practice, even on a portable PC running Windows over Wi-Fi ntp is 
usually synced to within a few milliseconds as soon as the system is 
booted.  Look at the daily boots of PC Puffin:



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