[ntp:questions] SNTP with 1ms of precision?

Rick Jones rick.jones2 at hp.com
Thu Jun 17 21:44:56 UTC 2010

David Woolley <david at ex.djwhome.demon.invalid> wrote:
> SNTP as used on Windows to access the Microsoft timeserver certainly
> can't.  Anything that runs on Windows that sets the clock on ever
> poll almost certainly can't for any reasonable application load.  On
> Linux you have to beware of interrupt latency, NIC interrupt
> aggregations.

I suspect there are interrupt aggregations on more than just Linux.  I
would expect every *nix and even Windows to have interrupt
aggregation/coalescing.  I would expect it to delay notification to
the host that the packet has arrived by anywhere between 5 and 20
microseconds, but that is an off-the-cuff estimate.

rick jones
Process shall set you free from the need for rational thought. 
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