[ntp:questions] Why is my precision=-15? I'm using a nano kernel.

David Taylor david-taylor at blueyonder.co.uk.invalid
Tue Jan 15 20:45:14 UTC 2013

On 15/01/2013 19:05, Chuck Swiger wrote:
> Hi--
> Out of ~100 emails from this group listing precisions in the modern format
> (ie, NTP-4.2.x), a histogram [1] of results is:
> 46 precision=-19
> 16 precision=-20
> 12 precision=-14
> 8  precision=-18
> 4  precision=-8
> 3  precision=-15
> 3  precision=-10
> 2  precision=-16
> 1  precision=-21
> 1  precision=-13
> 1  precision=-19
> 1  precision=-10
> One might do better using 'ntpq -crv' against published NTP servers or pool members to collect data.
> Regards,

For amusement, I knocked up a little DOS script and got the following:

FreeBSD 8.2 Intel Atom
PC Pixie
precision=-19, refid=PPS, system="FreeBSD/8.2-RELEASE-p6"
PC RasPi-1
precision=-18, refid=PPS, system="Linux/3.2.27-pps-g965b922-dirty"
PC RasPi-2
precision=-19, refid=PPS, system="Linux/3.2.27-pps-g965b922-dirty"
Windows Stratum-1
PC Alta Win-7/64
precision=-22, refid=PPS, system="Windows"
PC Bacchus Win-2000
precision=-18, refid=PPS, system="Windows"
PC Feenix Win-XP
precision=-18, refid=PPS, system="Windows"
Windows LAN-synced
PC Hydra Win-7/64
precision=-10, refid=, system="Windows"
PC Narvik Win-XP
precision=-21, refid=, system="Windows"
Windows Wi-Fi synced
PC Bergen Win-8
precision=-19, refid=, system="Windows"
PC Molde Win-7/64
precision=-10, refid=, system="Windows"
PC Ystad Win-7/32
precision=-10, refid=, system="Windows"

Hope that's of some interest.  The Windows systems without interpolation 
(Win-7) have a clock interval of about 1 ms, so precision=-10 seems 
correct.  PC Alta is Win-7/64, but has interpolation forced on.
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