NTPsec

Backup/Meinberg

Report generated: Wed Nov 20 16:43:00 2024 UTC
Start Time: Wed Nov 13 16:43:00 2024 UTC
End Time: Wed Nov 20 16:43:00 2024 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 -120.601 -55.608 -39.603 -7.671 81.723 120.069 235.961 121.326 175.677 35.828 0.873 µs -2.035 7.98
Local Clock Frequency Offset 0.557 0.604 0.783 1.159 1.640 1.957 2.129 0.857 1.352 0.265 1.165 ppm 49.88 213.5

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 0.340 0.470 0.558 1.031 3.376 11.082 22.560 2.818 10.612 1.716 1.447 µs 5.498 43.91

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 0.101 0.165 0.239 0.959 5.338 7.293 11.219 5.099 7.128 1.583 1.508 ppb 2.266 9.082

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 -120.601 -55.608 -39.603 -7.671 81.723 120.069 235.961 121.326 175.677 35.828 0.873 µs -2.035 7.98

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 0.557 0.604 0.783 1.159 1.640 1.957 2.129 0.857 1.352 0.265 1.165 ppm 49.88 213.5
Temp /dev/sda 39.000 40.000 40.000 41.000 44.000 46.000 47.000 4.000 6.000 1.238 41.724 °C
Temp /dev/sdb 50.000 50.000 51.000 52.000 60.000 61.000 62.000 9.000 11.000 2.473 52.959 °C
Temp /dev/sdc 49.000 51.000 51.000 53.000 56.000 58.000 58.000 5.000 7.000 1.430 52.657 °C
Temp /dev/sdd 56.000 56.000 57.000 59.000 68.000 69.000 70.000 11.000 13.000 2.899 59.719 °C
Temp /dev/sde 39.000 39.000 40.000 41.000 45.000 47.000 48.000 5.000 8.000 1.609 41.424 °C
Temp /dev/sdf 50.000 50.000 51.000 53.000 60.000 62.000 62.000 9.000 12.000 2.520 53.171 °C
Temp LM0 24.500 24.750 25.250 26.750 29.500 33.000 37.000 4.250 8.250 1.462 26.926 °C
Temp LM1 35.500 36.000 36.500 38.000 40.500 42.000 43.000 4.000 6.000 1.208 38.233 °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 39.000 40.000 40.000 41.000 44.000 46.000 47.000 4.000 6.000 1.238 41.725 °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 25.750 26.000 26.500 28.000 30.250 33.000 34.250 3.750 7.000 1.241 28.139 °C
Temp LM16 50.000 50.000 51.000 53.000 60.000 62.000 62.000 9.000 12.000 2.535 53.285 °C
Temp LM17 56.500 57.000 57.500 59.000 61.500 65.000 66.000 4.000 8.000 1.454 59.226 °C
Temp LM18 56.000 56.000 57.000 59.000 68.000 69.000 70.000 11.000 13.000 2.905 59.855 °C
Temp LM19 50.000 50.000 51.000 52.000 60.000 61.000 62.000 9.000 11.000 2.503 53.049 °C
Temp LM2 39.000 39.000 40.000 41.000 45.000 47.000 48.000 5.000 8.000 1.611 41.423 °C
Temp LM20 23.000 24.000 24.000 26.000 30.000 38.000 69.000 6.000 14.000 3.404 26.808 °C
Temp LM21 22.000 23.000 24.000 26.000 30.000 38.000 69.000 6.000 15.000 3.313 26.642 °C
Temp LM22 20.000 21.000 21.000 24.000 27.000 36.000 66.000 6.000 15.000 3.377 23.950 °C
Temp LM23 21.000 22.000 23.000 25.000 29.000 37.000 66.000 6.000 15.000 3.269 25.621 °C
Temp LM24 22.000 23.000 23.000 25.000 29.000 35.000 61.000 6.000 12.000 2.901 25.438 °C
Temp LM3 28.000 28.000 29.000 31.000 33.000 34.000 36.000 4.000 6.000 1.173 30.674 °C
Temp LM4 27.000 27.500 28.500 29.500 31.500 33.500 35.000 3.000 6.000 1.090 29.694 °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 23.000 23.500 24.000 26.000 30.000 39.000 69.000 6.000 15.500 3.387 26.293 °C
Temp LM7 56.000 56.000 57.000 59.000 61.000 65.000 66.000 4.000 9.000 1.495 59.000 °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 24.000 26.000 30.000 39.000 69.000 6.000 15.000 3.429 26.520 °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 56.500 56.500 57.500 59.000 61.500 65.000 66.000 4.000 8.500 1.459 59.229 °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) -689.290 -476.749 -363.058 44.902 249.899 311.737 353.711 612.957 788.486 175.915 9.635 µs -4.625 13.51

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 -1,106.926 -976.634 -603.416 40.897 412.197 605.907 709.435 1,015.613 1,582.541 300.009 -0.374 µs -4.801 14.21

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 -117.381 -51.579 -23.875 42.301 124.406 165.895 301.424 148.281 217.474 43.804 43.456 µs 0.7453 6.127

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 -568.333 -206.039 -13.698 40.299 103.569 257.512 601.164 117.267 463.551 66.054 40.485 µs -2.329 34.77

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) -120.602 -55.609 -39.604 -7.672 81.724 120.070 235.962 121.328 175.679 35.828 0.872 µs -2.035 7.98

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) 0.825 3.095 4.827 11.163 24.396 34.683 78.484 19.569 31.588 6.687 12.497 µs 5.454 26.11

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 2.912 5.244 7.237 14.809 32.962 50.120 2,427.238 25.725 44.876 61.955 19.063 µs 30.31 1091

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 1.238 3.419 5.354 23.983 58.526 78.032 3,474.600 53.172 74.613 56.701 26.640 µs 52.87 3192

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 0.870 2.841 4.672 12.182 39.073 127.562 296.996 34.401 124.721 22.104 17.219 µs 5.7 51.42

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) 0.102 0.384 0.624 2.553 12.352 43.477 129.069 11.728 43.093 7.634 4.403 µs 6.055 67.47

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 0.557 0.604 0.783 1.159 1.640 1.957 2.129 0.857 1.352 0.265 1.165 ppm 49.88 213.5
Local Clock Time Offset -120.601 -55.608 -39.603 -7.671 81.723 120.069 235.961 121.326 175.677 35.828 0.873 µs -2.035 7.98
Local RMS Frequency Jitter 0.101 0.165 0.239 0.959 5.338 7.293 11.219 5.099 7.128 1.583 1.508 ppb 2.266 9.082
Local RMS Time Jitter 0.340 0.470 0.558 1.031 3.376 11.082 22.560 2.818 10.612 1.716 1.447 µs 5.498 43.91
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.825 3.095 4.827 11.163 24.396 34.683 78.484 19.569 31.588 6.687 12.497 µs 5.454 26.11
Server Jitter 204.17.205.1 2.912 5.244 7.237 14.809 32.962 50.120 2,427.238 25.725 44.876 61.955 19.063 µs 30.31 1091
Server Jitter 204.17.205.24 1.238 3.419 5.354 23.983 58.526 78.032 3,474.600 53.172 74.613 56.701 26.640 µs 52.87 3192
Server Jitter 204.17.205.27 0.870 2.841 4.672 12.182 39.073 127.562 296.996 34.401 124.721 22.104 17.219 µs 5.7 51.42
Server Jitter SHM(0) 0.102 0.384 0.624 2.553 12.352 43.477 129.069 11.728 43.093 7.634 4.403 µs 6.055 67.47
Server Offset 2001:470:e815::8 (spidey.rellim.com) -689.290 -476.749 -363.058 44.902 249.899 311.737 353.711 612.957 788.486 175.915 9.635 µs -4.625 13.51
Server Offset 204.17.205.1 -1,106.926 -976.634 -603.416 40.897 412.197 605.907 709.435 1,015.613 1,582.541 300.009 -0.374 µs -4.801 14.21
Server Offset 204.17.205.24 -117.381 -51.579 -23.875 42.301 124.406 165.895 301.424 148.281 217.474 43.804 43.456 µs 0.7453 6.127
Server Offset 204.17.205.27 -568.333 -206.039 -13.698 40.299 103.569 257.512 601.164 117.267 463.551 66.054 40.485 µs -2.329 34.77
Server Offset SHM(0) -120.602 -55.609 -39.604 -7.672 81.724 120.070 235.962 121.328 175.679 35.828 0.872 µs -2.035 7.98
Temp /dev/sda 39.000 40.000 40.000 41.000 44.000 46.000 47.000 4.000 6.000 1.238 41.724 °C
Temp /dev/sdb 50.000 50.000 51.000 52.000 60.000 61.000 62.000 9.000 11.000 2.473 52.959 °C
Temp /dev/sdc 49.000 51.000 51.000 53.000 56.000 58.000 58.000 5.000 7.000 1.430 52.657 °C
Temp /dev/sdd 56.000 56.000 57.000 59.000 68.000 69.000 70.000 11.000 13.000 2.899 59.719 °C
Temp /dev/sde 39.000 39.000 40.000 41.000 45.000 47.000 48.000 5.000 8.000 1.609 41.424 °C
Temp /dev/sdf 50.000 50.000 51.000 53.000 60.000 62.000 62.000 9.000 12.000 2.520 53.171 °C
Temp LM0 24.500 24.750 25.250 26.750 29.500 33.000 37.000 4.250 8.250 1.462 26.926 °C
Temp LM1 35.500 36.000 36.500 38.000 40.500 42.000 43.000 4.000 6.000 1.208 38.233 °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 39.000 40.000 40.000 41.000 44.000 46.000 47.000 4.000 6.000 1.238 41.725 °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 25.750 26.000 26.500 28.000 30.250 33.000 34.250 3.750 7.000 1.241 28.139 °C
Temp LM16 50.000 50.000 51.000 53.000 60.000 62.000 62.000 9.000 12.000 2.535 53.285 °C
Temp LM17 56.500 57.000 57.500 59.000 61.500 65.000 66.000 4.000 8.000 1.454 59.226 °C
Temp LM18 56.000 56.000 57.000 59.000 68.000 69.000 70.000 11.000 13.000 2.905 59.855 °C
Temp LM19 50.000 50.000 51.000 52.000 60.000 61.000 62.000 9.000 11.000 2.503 53.049 °C
Temp LM2 39.000 39.000 40.000 41.000 45.000 47.000 48.000 5.000 8.000 1.611 41.423 °C
Temp LM20 23.000 24.000 24.000 26.000 30.000 38.000 69.000 6.000 14.000 3.404 26.808 °C
Temp LM21 22.000 23.000 24.000 26.000 30.000 38.000 69.000 6.000 15.000 3.313 26.642 °C
Temp LM22 20.000 21.000 21.000 24.000 27.000 36.000 66.000 6.000 15.000 3.377 23.950 °C
Temp LM23 21.000 22.000 23.000 25.000 29.000 37.000 66.000 6.000 15.000 3.269 25.621 °C
Temp LM24 22.000 23.000 23.000 25.000 29.000 35.000 61.000 6.000 12.000 2.901 25.438 °C
Temp LM3 28.000 28.000 29.000 31.000 33.000 34.000 36.000 4.000 6.000 1.173 30.674 °C
Temp LM4 27.000 27.500 28.500 29.500 31.500 33.500 35.000 3.000 6.000 1.090 29.694 °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 23.000 23.500 24.000 26.000 30.000 39.000 69.000 6.000 15.500 3.387 26.293 °C
Temp LM7 56.000 56.000 57.000 59.000 61.000 65.000 66.000 4.000 9.000 1.495 59.000 °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 24.000 26.000 30.000 39.000 69.000 6.000 15.000 3.429 26.520 °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 56.500 56.500 57.500 59.000 61.500 65.000 66.000 4.000 8.500 1.459 59.229 °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.
kurtosis, Kurt:
The kurtosis of a random variable X is the fourth standardized moment and is a dimension-less ratio. ntpviz uses the Pearson's moment coefficient of 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".
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 Pearson's moment coefficient of skewness. Wikipedia describes it best: "The qualitative interpretation of the skew is complicated and unintuitive."
A normal distribution has a skewness of zero.
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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