Unusually for me, the configuration and code on my reference clock test machine has been static for the last two days UTC. I've posted loopstats and graphs for that period on http;//davehart.net/ntp/ refclock/
Most of all, the low jitter averaging under 3us suggests I don't have a lot of room left for improvement before running up against the claimed +/-1us accuracy of the GPS 18x LVC's PPS: http://davehart.net/ntp/refclock/refclock-20090315-20090316-jitter.jpg http://tinyurl.com/c4juho To understand the two spikes in jitter look at either: http://davehart.net/ntp/refclock/refclock-20090315-20090316-combined.jpg http://tinyurl.com/dg7gsq (combining frequency and offset) or separately: http://davehart.net/ntp/refclock/refclock-20090315-20090316-freq.jpg http://tinyurl.com/c85z4r http://davehart.net/ntp/refclock/refclock-20090315-20090316-offset.jpg http://tinyurl.com/dybvf3 The slow positive climb in frequency most of the time corresponds to the temperature slowly declining. There are a few transients pulling the frequency up briefly, probably caused by a door being opened letting in cold air. The dramatic frequency drop in the middle is caused by a furnace cycle, bigger than most suggesting the thermostat was turned up. I don't have temperature monitoring but it's on the 2nd floor with forced air heat controlled by a single thermostat on the 1st floor. The temperature upstairs continues to rise for some time after the thermostat turns off the heat. I wish this was completely representative of the new interpolation scheme in my recent releases. There is an unexplained jitter variability between runs of ntpd. Some runs it's several times higher, but still an order of magnitude better than the previous interpolation approach. I'm expecting but have not yet seen demonstrated that the new scheme works better on machines with 10ms clock periods (all mine have 15.6ms clock periods). Cheers, Dave Hart _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
