[ntp:hackers] ntpd.exe interpolation test version

Dave Hart davehart at davehart.com
Tue Feb 24 05:57:38 UTC 2009


> This version is hard-coded to sample the
> counter 27 times per second and keeps 64 samples, which
> seems to work for my machines.

Correction, it uses a 27 msec timer interval, so as it says
at startup:

HZ 64.000 using 27 msec timer 37.037 Hz

Meaning the system clock updates 64 times a second and ntpd
will sample it every 27 msec or 37 times per second.  On
Vista with -M interpolation is disabled and you won't see
the message above, instead:

using native clock directly

is logged.

While it should take a little jitter out of normal
network-only ntpd operation, the real improvement can be
seen only if you're using a refclock that's getting you no
worse than a couple of milliseconds jitter now.

Cheers,
Dave Hart


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