Unruh wrote: > "David J Taylor" [] >> Another PC in the same room running a FreeBSD system has about half >> the jitter, but far less offset - PC Pixie at the top: > >> http://www.satsignal.eu/mrtg/performance_ntp.php > > That looks much more like the kind of timing I get on my Linux system. > driven by a PPS from a Garmin 18LVC. > > I assume that the rate is also far more constant on that system.
Not far more constant, no. On the FreeBSD/Pentium-133 system over the last 72 hours the frequncy varied between about -0.6ppm to +0.4ppm from the mean, and on the Windows XP system from about -1.4ppm to +1.1ppm from the mean. So about 1ppm variation as opposed to 2.5ppm, about 40% of the frequency variation. As far as I can tell, the NTP offset is more a function of the control loop parameters than of the actual hardware (with ~150us offsets and yet only 2.5us jitter). There is another issue - version numbers. The FreeBSD runs 4.2.0-a from May 2005, the Windows 4.2.4.p6 from 2009. I don't know whether there may have been internal changes affecting the offset compared to the jitter. I have checked for a temperature monitoring SNMP plug-in, but not found a compatible one as yet. Yes, it would be helpful to have more Windows testers. Cheers, David _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
