[ntp:questions] NTP server with Garmin GPS 18 LVC

unruh unruh at invalid.ca
Thu Dec 19 01:18:19 UTC 2013

On 2013-12-18, Adrian P <ntp at pascalau.ro> wrote:
> Everywhere is written that FreeBSD is the best OS for time keeper,
> since its kernel supports nanosecond accuracies. However, if GPS 18x

So does Linux. 
But the interrupt processing ( and eventhe clock reading times) are
nowhere near that accurate. The interrupt processing is on the order of
1-2us accuracy, with possible delays of up to 10us occasionally (because
other interrupts do not allow themselved to be interrupted for example).

> LVC PPS signal has only microsecond accuracy, then I suppose there is
> no point on using FreeBSD, any linux would be okay as well. So what do
> you think, looking from NTP point of view only, is this nanosecond
> accuracy the only reason why someone would use FreeBSD, or there are
> some other reasons as well? I see you have experience with all kind of
> OSes.

I would stick with linux.

> Many thanks,
> Adrian

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