NTPsec

Backup/Meinberg

Report generated: Tue Dec 16 16:43:01 2025 UTC
Start Time: Tue Dec 9 16:43:00 2025 UTC
End Time: Tue Dec 16 16:43:00 2025 UTC
Report Period: 7.0 days

Daily stats   Weekly stats  

Local Clock Time/Frequency Offsets

local offset plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Time Offset -94.647 -57.025 -21.379 -4.319 45.868 111.602 190.817 67.247 168.627 24.220 -0.044 µs 2.516 16.79
Local Clock Frequency Offset 11.106 11.138 11.239 11.497 11.673 11.837 11.869 0.434 0.699 0.130 11.481 ppm -0.2756 3.603

The time and frequency offsets between the ntpd calculated time and the local system clock. Showing frequency offset (red, in parts per million, scale on right) and the time offset (blue, in μs, scale on left). Quick changes in time offset will lead to larger frequency offsets.

These are fields 3 (time) and 4 (frequency) from the loopstats log file.



Local RMS Time Jitter

local jitter plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Time Jitter 0.406 0.561 0.655 1.057 3.475 8.740 12.823 2.820 8.179 1.363 1.442 µs 4.381 25.83

The RMS Jitter of the local clock offset. In other words, how fast the local clock offset is changing.

Lower is better. An ideal system would be a horizontal line at 0μs.

RMS jitter is field 5 in the loopstats log file.



Local RMS Frequency Jitter

local stability plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Frequency Jitter 0.068 0.119 0.167 0.578 3.205 6.232 10.207 3.038 6.113 1.160 0.916 ppb 3.6 19.33

The RMS Frequency Jitter (aka wander) of the local clock's frequency. In other words, how fast the local clock changes frequency.

Lower is better. An ideal clock would be a horizontal line at 0ppm.

RMS Frequency Jitter is field 6 in the loopstats log file.



Local Clock Time Offset Histogram

local offset histogram plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Offset -94.647 -57.025 -21.379 -4.319 45.868 111.602 190.817 67.247 168.627 24.220 -0.044 µs 2.516 16.79

The clock offsets of the local clock as a histogram.

The Local Clock Offset is field 3 from the loopstats log file.



Local Temperatures

local temps plot

Local temperatures. These will be site-specific depending upon what temperature sensors you collect data from. Temperature changes affect the local clock crystal frequency and stability. The math of how temperature changes frequency is complex, and also depends on crystal aging. So there is no easy way to correct for it in software. This is the single most important component of frequency drift.

The Local Temperatures are from field 3 from the tempstats log file.



Local Frequency/Temp

local freq temps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset 11.106 11.138 11.239 11.497 11.673 11.837 11.869 0.434 0.699 0.130 11.481 ppm -0.2756 3.603
Temp /dev/sda 41.000 42.000 42.000 43.000 44.000 45.000 47.000 2.000 3.000 0.644 42.895 °C
Temp /dev/sdb 52.000 52.000 53.000 54.000 60.000 61.000 62.000 7.000 9.000 2.037 54.273 °C
Temp /dev/sdc 53.000 53.000 53.000 54.000 54.000 56.000 60.000 1.000 3.000 0.703 53.790 °C
Temp /dev/sdd 59.000 59.000 59.000 61.000 69.000 70.000 70.000 10.000 11.000 2.536 61.340 °C
Temp /dev/sde 41.000 42.000 42.000 43.000 44.000 45.000 46.000 2.000 3.000 0.681 42.899 °C
Temp /dev/sdf 52.000 52.000 53.000 54.000 61.000 62.000 62.000 8.000 10.000 2.108 54.757 °C
Temp LM0 25.250 25.500 25.750 27.000 29.000 38.000 47.750 3.250 12.500 1.749 27.247 °C
Temp LM1 38.000 38.500 39.000 40.500 41.000 42.000 43.500 2.000 3.500 0.626 40.254 °C
Temp LM10 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM11 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM12 41.000 42.000 42.000 43.000 44.000 45.000 47.000 2.000 3.000 0.646 42.893 °C
Temp LM13 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp LM14 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C
Temp LM15 26.500 26.750 27.000 28.250 29.750 33.750 38.000 2.750 7.000 1.082 28.387 °C
Temp LM16 52.000 52.000 53.000 54.000 61.000 62.000 63.000 8.000 10.000 2.127 54.845 °C
Temp LM17 57.500 58.000 58.500 59.500 61.000 63.500 65.000 2.500 5.500 0.920 59.726 °C
Temp LM18 59.000 59.000 59.000 61.000 69.000 70.000 70.000 10.000 11.000 2.555 61.448 °C
Temp LM19 52.000 52.000 53.000 54.000 60.000 61.000 62.000 7.000 9.000 2.062 54.375 °C
Temp LM2 41.000 42.000 42.000 43.000 44.000 45.000 46.000 2.000 3.000 0.711 42.881 °C
Temp LM20 23.000 24.000 25.000 26.000 29.000 62.000 100.000 4.000 38.000 5.027 27.131 °C
Temp LM21 23.000 24.000 25.000 26.000 29.000 57.000 100.000 4.000 33.000 4.673 27.010 °C
Temp LM22 20.000 22.000 22.000 24.000 27.000 57.000 94.000 5.000 35.000 4.700 24.526 °C
Temp LM23 21.000 22.000 23.000 25.000 28.000 59.000 94.000 5.000 37.000 4.690 25.466 °C
Temp LM24 22.000 23.000 24.000 25.000 28.000 52.000 88.000 4.000 29.000 4.322 25.685 °C
Temp LM3 30.000 30.000 30.000 32.000 32.000 35.000 38.000 2.000 5.000 0.812 31.580 °C
Temp LM4 28.000 28.000 28.500 30.000 31.000 32.500 34.000 2.500 4.500 0.885 29.929 °C
Temp LM5 24.000 24.000 24.000 24.000 24.000 24.000 24.000 0.000 0.000 0.000 24.000 °C
Temp LM6 29.000 29.000 29.000 29.000 29.000 29.000 29.000 0.000 0.000 0.000 29.000 °C
Temp LM7 57.000 58.000 58.000 59.000 61.000 63.000 65.000 3.000 5.000 0.954 59.541 °C
Temp LM8 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM9 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp ZONE0 23.000 24.000 25.000 26.000 29.000 60.000 99.000 4.000 36.000 5.116 26.968 °C
Temp ZONE1 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp ZONE2 57.500 58.000 58.500 59.500 61.000 63.500 65.000 2.500 5.500 0.923 59.727 °C
Temp ZONE3 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C

The frequency offsets and temperatures. Showing frequency offset (red, in parts per million, scale on right) and the temperatures.

These are field 4 (frequency) from the loopstats log file, and field 3 from the tempstats log file.



Server Offsets

peer offsets plot

The offset of all refclocks and servers. This can be useful to see if offset changes are happening in a single clock or all clocks together.

Clock Offset is field 5 in the peerstats log file.



Server Offset 2001:470:e815::8 (spidey.rellim.com)

peer offset 2001:470:e815::8 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2001:470:e815::8 (spidey.rellim.com) -11.051 -0.802 -0.009 0.066 0.982 1.871 3.700 0.991 2.673 0.564 0.184 ms -6.259 131

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 204.17.205.1

peer offset 204.17.205.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.1 -0.644 -0.408 -0.008 0.631 1.280 1.680 2.258 1.289 2.089 0.418 0.628 ms 0.1521 3.392

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 204.17.205.24

peer offset 204.17.205.24 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.24 -45.650 -15.639 -1.564 0.043 0.677 2.889 13.342 2.241 18.528 3.111 -0.373 ms -7.531 76.44

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 204.17.205.27

peer offset 204.17.205.27 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.27 -1.082 -0.694 -0.154 0.053 0.541 1.223 1.404 0.694 1.918 0.263 0.108 ms 1.294 11.12

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset SHM(0)

peer offset SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset SHM(0) -94.648 -57.026 -21.380 -4.320 45.869 111.603 190.818 67.249 168.629 24.221 -0.044 µs 2.516 16.79

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Jitters

peer jitters plot

The RMS Jitter of all refclocks and servers. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 2001:470:e815::8 (spidey.rellim.com)

peer jitter 2001:470:e815::8 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.001 0.004 0.006 0.027 0.091 0.238 6.334 0.085 0.235 0.141 0.044 ms 28.9 1100

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 204.17.205.1

peer jitter 204.17.205.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.1 2.373 6.065 8.320 17.703 40.744 55.094 131.676 32.424 49.029 11.140 20.523 µs 2.418 16.17

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 204.17.205.24

peer jitter 204.17.205.24 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.24 0.000 0.004 0.007 0.027 9.695 21.185 119.575 9.688 21.180 5.273 1.623 ms 8.892 133.6

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 204.17.205.27

peer jitter 204.17.205.27 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.27 2.451 5.089 7.869 53.802 142.614 170.610 250.242 134.745 165.521 45.569 60.752 µs 0.5884 2.408

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter SHM(0)

peer jitter SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(0) 0.123 0.439 0.733 2.728 11.705 38.983 72.063 10.972 38.544 6.228 4.286 µs 5.474 40.78

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset 11.106 11.138 11.239 11.497 11.673 11.837 11.869 0.434 0.699 0.130 11.481 ppm -0.2756 3.603
Local Clock Time Offset -94.647 -57.025 -21.379 -4.319 45.868 111.602 190.817 67.247 168.627 24.220 -0.044 µs 2.516 16.79
Local RMS Frequency Jitter 0.068 0.119 0.167 0.578 3.205 6.232 10.207 3.038 6.113 1.160 0.916 ppb 3.6 19.33
Local RMS Time Jitter 0.406 0.561 0.655 1.057 3.475 8.740 12.823 2.820 8.179 1.363 1.442 µs 4.381 25.83
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.001 0.004 0.006 0.027 0.091 0.238 6.334 0.085 0.235 0.141 0.044 ms 28.9 1100
Server Jitter 204.17.205.1 2.373 6.065 8.320 17.703 40.744 55.094 131.676 32.424 49.029 11.140 20.523 µs 2.418 16.17
Server Jitter 204.17.205.24 0.000 0.004 0.007 0.027 9.695 21.185 119.575 9.688 21.180 5.273 1.623 ms 8.892 133.6
Server Jitter 204.17.205.27 2.451 5.089 7.869 53.802 142.614 170.610 250.242 134.745 165.521 45.569 60.752 µs 0.5884 2.408
Server Jitter SHM(0) 0.123 0.439 0.733 2.728 11.705 38.983 72.063 10.972 38.544 6.228 4.286 µs 5.474 40.78
Server Offset 2001:470:e815::8 (spidey.rellim.com) -11.051 -0.802 -0.009 0.066 0.982 1.871 3.700 0.991 2.673 0.564 0.184 ms -6.259 131
Server Offset 204.17.205.1 -0.644 -0.408 -0.008 0.631 1.280 1.680 2.258 1.289 2.089 0.418 0.628 ms 0.1521 3.392
Server Offset 204.17.205.24 -45.650 -15.639 -1.564 0.043 0.677 2.889 13.342 2.241 18.528 3.111 -0.373 ms -7.531 76.44
Server Offset 204.17.205.27 -1.082 -0.694 -0.154 0.053 0.541 1.223 1.404 0.694 1.918 0.263 0.108 ms 1.294 11.12
Server Offset SHM(0) -94.648 -57.026 -21.380 -4.320 45.869 111.603 190.818 67.249 168.629 24.221 -0.044 µs 2.516 16.79
Temp /dev/sda 41.000 42.000 42.000 43.000 44.000 45.000 47.000 2.000 3.000 0.644 42.895 °C
Temp /dev/sdb 52.000 52.000 53.000 54.000 60.000 61.000 62.000 7.000 9.000 2.037 54.273 °C
Temp /dev/sdc 53.000 53.000 53.000 54.000 54.000 56.000 60.000 1.000 3.000 0.703 53.790 °C
Temp /dev/sdd 59.000 59.000 59.000 61.000 69.000 70.000 70.000 10.000 11.000 2.536 61.340 °C
Temp /dev/sde 41.000 42.000 42.000 43.000 44.000 45.000 46.000 2.000 3.000 0.681 42.899 °C
Temp /dev/sdf 52.000 52.000 53.000 54.000 61.000 62.000 62.000 8.000 10.000 2.108 54.757 °C
Temp LM0 25.250 25.500 25.750 27.000 29.000 38.000 47.750 3.250 12.500 1.749 27.247 °C
Temp LM1 38.000 38.500 39.000 40.500 41.000 42.000 43.500 2.000 3.500 0.626 40.254 °C
Temp LM10 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM11 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM12 41.000 42.000 42.000 43.000 44.000 45.000 47.000 2.000 3.000 0.646 42.893 °C
Temp LM13 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp LM14 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C
Temp LM15 26.500 26.750 27.000 28.250 29.750 33.750 38.000 2.750 7.000 1.082 28.387 °C
Temp LM16 52.000 52.000 53.000 54.000 61.000 62.000 63.000 8.000 10.000 2.127 54.845 °C
Temp LM17 57.500 58.000 58.500 59.500 61.000 63.500 65.000 2.500 5.500 0.920 59.726 °C
Temp LM18 59.000 59.000 59.000 61.000 69.000 70.000 70.000 10.000 11.000 2.555 61.448 °C
Temp LM19 52.000 52.000 53.000 54.000 60.000 61.000 62.000 7.000 9.000 2.062 54.375 °C
Temp LM2 41.000 42.000 42.000 43.000 44.000 45.000 46.000 2.000 3.000 0.711 42.881 °C
Temp LM20 23.000 24.000 25.000 26.000 29.000 62.000 100.000 4.000 38.000 5.027 27.131 °C
Temp LM21 23.000 24.000 25.000 26.000 29.000 57.000 100.000 4.000 33.000 4.673 27.010 °C
Temp LM22 20.000 22.000 22.000 24.000 27.000 57.000 94.000 5.000 35.000 4.700 24.526 °C
Temp LM23 21.000 22.000 23.000 25.000 28.000 59.000 94.000 5.000 37.000 4.690 25.466 °C
Temp LM24 22.000 23.000 24.000 25.000 28.000 52.000 88.000 4.000 29.000 4.322 25.685 °C
Temp LM3 30.000 30.000 30.000 32.000 32.000 35.000 38.000 2.000 5.000 0.812 31.580 °C
Temp LM4 28.000 28.000 28.500 30.000 31.000 32.500 34.000 2.500 4.500 0.885 29.929 °C
Temp LM5 24.000 24.000 24.000 24.000 24.000 24.000 24.000 0.000 0.000 0.000 24.000 °C
Temp LM6 29.000 29.000 29.000 29.000 29.000 29.000 29.000 0.000 0.000 0.000 29.000 °C
Temp LM7 57.000 58.000 58.000 59.000 61.000 63.000 65.000 3.000 5.000 0.954 59.541 °C
Temp LM8 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM9 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp ZONE0 23.000 24.000 25.000 26.000 29.000 60.000 99.000 4.000 36.000 5.116 26.968 °C
Temp ZONE1 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp ZONE2 57.500 58.000 58.500 59.500 61.000 63.500 65.000 2.500 5.500 0.923 59.727 °C
Temp ZONE3 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C
Summary as CSV file


This server:

CPU: Quad core Intel Xeon E3-1241 v3
Kernel: config.gz
Motherboard: Supermicro X10SAE
OS: Gentoo stable
GPS; Meinberg GPS180PEX
GPS/PPS server: gpsd
NTP server: NTPsec
ntp.conf: current
ntp.log: current

Notes:

Notes:
03:20Z 20 Dec 2018 Change poll from 8s to 4s.  4s seems best.
01:30Z 20 Dec 2018 Change poll from 2s to 8s.
23:00Z 20 Dec 2018 Change poll from 4s to 2s.
22:00Z 20 Dec 2018 Change poll from 64s to 4s.
21:40  19 Dec 2018 -- just started

Poll:
64s   SHM(0) offset StdDev 34.5 us, jitter 5.3 us
8s    8s better jitter than 4s, but worse offset than 4s
4s    SHM(0) offset mean 0 ns StdDev 481 ns, jitter 449 ns StdDev 250 ns
      better than 2s, almost unstable
2s

Glossary:

frequency offset:
The difference between the ntpd calculated frequency and the local system clock frequency (usually in parts per million, ppm)
jitter, dispersion:
The short term change in a value. NTP measures Local Time Jitter, Refclock Jitter, and Server Jitter in seconds. Local Frequency Jitter is in ppm or ppb.
ms, millisecond:
One thousandth of a second = 0.001 seconds, 1e-3 seconds
mu, mean:
The arithmetic mean: the sum of all the values divided by the number of values. The formula for mu is: "mu = (∑xi) / N". Where xi denotes the data points and N is the number of data points.
ns, nanosecond:
One billionth of a second, also one thousandth of a microsecond, 0.000000001 seconds and 1e-9 seconds.
percentile:
The value below which a given percentage of values fall.
ppb, parts per billion:
Ratio between two values. These following are all the same: 1 ppb, one in one billion, 1/1,000,000,000, 0.000,000,001, 1e-9 and 0.000,000,1%
ppm, parts per million:
Ratio between two values. These following are all the same: 1 ppm, one in one million, 1/1,000,000, 0.000,001, and 0.000,1%
‰, parts per thousand:
Ratio between two values. These following are all the same: 1 ‰. one in one thousand, 1/1,000, 0.001, and 0.1%
refclock:
Reference clock, a local GPS module or other local source of time.
remote clock:
Any clock reached over the network, LAN or WAN. Also called a peer or server.
time offset:
The difference between the ntpd calculated time and the local system clock's time. Also called phase offset.
σ, sigma:
Sigma denotes the standard deviation (SD) and is centered on the arithmetic mean of the data set. The SD is simply the square root of the variance of the data set. Two sigma is simply twice the standard deviation. Three sigma is three times sigma. Smaller is better.
The formula for sigma is: "σ = √[ ∑(xi-mu)^2 / N ]". Where xi denotes the data points and N is the number of data points.
Skewness, Skew:
The skewness of a random variable X is the third standardized moment and is a dimension-less ratio. ntpviz uses the FIsher-Pearson moment of skewness. There are other different ways to calculate Skewness Wikipedia describes Skewness best: "The qualitative interpretation of the skew is complicated and unintuitive."
A normal distribution has a skewness of zero.
Kurtosis, Kurt:
The kurtosis of a random variable X is the fourth standardized moment and is a dimension-less ratio. ntpviz uses standard Kurtosis. There are other different ways to calculate Kurtosis.
A normal distribution has a Kurtosis of three. NIST describes a kurtosis over three as "heavy tailed" and one under three as "light tailed".
upstream clock:
Any server or reference clock used as a source of time.
µs, us, microsecond:
One millionth of a second, also one thousandth of a millisecond, 0.000,001 seconds, and 1e-6 seconds.



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