[time-nuts] ntpd not talking to gpsd
Hal Murray
hmurray at megapathdsl.net
Wed Apr 2 03:13:15 EDT 2008
> server 127.127.28.0 minpoll 4 maxpoll 4
Speaking of gpsd and ntpd...
That minpoll/maxpoll stuff is trying to work around a bug/oversight in ntpd.
The current code grabs one sample per polling interval. The right way is to
grab a sample every second and filter/average them over a polling interval.
ntpd had code to do all the hard work. I've got a patch for the shared
memory refclock driver that takes advantage of that. Results are here:
http://www.megapathdsl.net/~hmurray/ntp/GPS18USB-SHM-off.gif
http://www.megapathdsl.net/~hmurray/ntp/GPS18USB-SHM-jit.gif
A long time ago, I asked on comp.protocols.time.ntp but nobody responded.
Is anybody here willing to help test it? If so, please contact me off-list.
--
These are my opinions, not necessarily my employer's. I hate spam.
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