NTPsec

Backup/Meinberg

Report generated: Fri Jul 12 15:43:00 2024 UTC
Start Time: Fri Jul 5 15:43:00 2024 UTC
End Time: Fri Jul 12 15:43:00 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 -48.001 -20.045 -12.950 -0.980 16.615 39.117 103.503 29.565 59.162 11.864 0.899 µs -1.894 12.61
Local Clock Frequency Offset 2.279 2.287 2.420 2.807 3.070 3.093 3.108 0.650 0.806 0.204 2.775 ppm 2037 2.612e+04

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 0.225 0.320 0.362 0.513 1.365 4.020 8.944 1.003 3.700 0.687 0.664 µs 6.074 48.72

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 0.030 0.053 0.098 0.487 1.106 2.683 4.962 1.008 2.630 0.464 0.559 ppb 4.738 32.91

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 -48.001 -20.045 -12.950 -0.980 16.615 39.117 103.503 29.565 59.162 11.864 0.899 µs -1.894 12.61

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 2.279 2.287 2.420 2.807 3.070 3.093 3.108 0.650 0.806 0.204 2.775 ppm 2037 2.612e+04
Temp /dev/sda 45.000 45.000 46.000 49.000 50.000 51.000 53.000 4.000 6.000 1.350 48.370 °C
Temp /dev/sdb 55.000 55.000 57.000 60.000 65.000 68.000 69.000 8.000 13.000 2.413 59.941 °C
Temp /dev/sdc 56.000 56.000 58.000 60.000 61.000 63.000 67.000 3.000 7.000 1.470 59.525 °C
Temp /dev/sdd 62.000 62.000 63.000 66.000 74.000 76.000 77.000 11.000 14.000 2.871 66.680 °C
Temp /dev/sde 44.000 45.000 46.000 48.000 51.000 53.000 54.000 5.000 8.000 1.626 48.276 °C
Temp /dev/sdf 55.000 56.000 57.000 60.000 66.000 69.000 69.000 9.000 13.000 2.553 60.375 °C
Temp LM0 38.750 39.000 40.000 42.000 43.500 43.750 46.000 3.500 4.750 1.163 41.757 °C
Temp LM1 43.500 44.500 44.500 46.500 48.000 48.500 50.000 3.500 4.000 1.117 46.437 °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 45.000 45.000 46.000 49.000 50.000 51.000 53.000 4.000 6.000 1.350 48.369 °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 37.750 38.000 39.000 41.500 43.250 43.250 44.250 4.250 5.250 1.313 41.208 °C
Temp LM16 56.000 56.000 57.000 60.000 66.000 69.000 69.000 9.000 13.000 2.602 60.564 °C
Temp LM17 64.000 64.000 65.000 67.000 69.000 72.000 73.000 4.000 8.000 1.425 67.105 °C
Temp LM18 62.000 62.000 64.000 66.000 74.000 76.000 77.000 10.000 14.000 2.907 66.894 °C
Temp LM19 56.000 56.000 57.000 60.000 65.000 69.000 69.000 8.000 13.000 2.415 60.123 °C
Temp LM2 44.000 45.000 46.000 48.000 51.000 53.000 53.000 5.000 8.000 1.619 48.286 °C
Temp LM20 54.000 57.000 58.000 61.000 64.000 66.000 73.000 6.000 9.000 1.840 61.329 °C
Temp LM21 54.000 57.000 58.000 61.000 64.000 66.000 73.000 6.000 9.000 1.841 61.332 °C
Temp LM22 44.000 46.000 47.000 50.000 52.000 55.000 67.000 5.000 9.000 1.778 49.650 °C
Temp LM23 42.000 44.000 44.000 46.000 49.000 52.000 66.000 5.000 8.000 1.888 46.523 °C
Temp LM24 40.000 41.000 42.000 44.000 46.000 49.000 65.000 4.000 8.000 1.863 43.938 °C
Temp LM3 37.000 37.000 38.000 40.000 41.000 42.000 43.000 3.000 5.000 1.159 39.687 °C
Temp LM4 34.500 34.500 36.000 38.000 40.000 40.000 40.500 4.000 5.500 1.298 38.006 °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 54.500 58.000 59.000 61.000 63.000 65.000 73.500 4.000 7.000 1.567 61.129 °C
Temp LM7 64.000 64.000 65.000 67.000 69.000 72.000 73.000 4.000 8.000 1.408 66.919 °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 55.000 57.000 59.000 61.000 64.000 66.000 73.000 5.000 9.000 1.784 61.397 °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 64.000 64.000 65.000 67.000 69.000 72.000 73.000 4.000 8.000 1.428 67.109 °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) -1.403 -1.179 -0.191 0.008 0.396 1.426 2.078 0.586 2.605 0.315 0.020 ms -2.42 19.33

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 -551.549 -433.225 -309.434 -7.396 213.297 403.476 457.204 522.731 836.701 166.100 -19.409 µs -5.059 13.57

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 -28.141 -10.462 7.839 60.357 84.962 109.792 192.656 77.123 120.254 23.514 56.748 µs 6.51 18.22

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 -355.201 -77.342 -4.088 34.556 67.653 110.059 297.521 71.741 187.401 33.839 32.325 µs -3.632 39.66

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) -48.002 -20.046 -12.950 -0.981 16.616 39.118 103.504 29.566 59.164 11.865 0.899 µs -1.894 12.61

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) 0.546 1.074 1.782 4.996 32.714 93.798 178.391 30.932 92.724 15.674 9.071 µs 3.849 27.45

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 0.686 1.741 2.707 8.398 22.000 29.372 321.177 19.293 27.631 11.456 10.314 µs 18.29 481.2

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 0.001 0.002 0.003 0.007 0.055 0.073 7.630 0.052 0.072 0.182 0.020 ms 30.66 1124

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 0.603 1.313 2.249 7.101 24.536 70.950 175.800 22.287 69.637 12.699 10.271 µs 5.314 47.04

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) 0.105 0.244 0.358 1.127 3.624 13.664 47.634 3.266 13.420 2.773 1.675 µs 7.654 89.7

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 2.279 2.287 2.420 2.807 3.070 3.093 3.108 0.650 0.806 0.204 2.775 ppm 2037 2.612e+04
Local Clock Time Offset -48.001 -20.045 -12.950 -0.980 16.615 39.117 103.503 29.565 59.162 11.864 0.899 µs -1.894 12.61
Local RMS Frequency Jitter 0.030 0.053 0.098 0.487 1.106 2.683 4.962 1.008 2.630 0.464 0.559 ppb 4.738 32.91
Local RMS Time Jitter 0.225 0.320 0.362 0.513 1.365 4.020 8.944 1.003 3.700 0.687 0.664 µs 6.074 48.72
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.546 1.074 1.782 4.996 32.714 93.798 178.391 30.932 92.724 15.674 9.071 µs 3.849 27.45
Server Jitter 204.17.205.1 0.686 1.741 2.707 8.398 22.000 29.372 321.177 19.293 27.631 11.456 10.314 µs 18.29 481.2
Server Jitter 204.17.205.24 0.001 0.002 0.003 0.007 0.055 0.073 7.630 0.052 0.072 0.182 0.020 ms 30.66 1124
Server Jitter 204.17.205.27 0.603 1.313 2.249 7.101 24.536 70.950 175.800 22.287 69.637 12.699 10.271 µs 5.314 47.04
Server Jitter SHM(0) 0.105 0.244 0.358 1.127 3.624 13.664 47.634 3.266 13.420 2.773 1.675 µs 7.654 89.7
Server Offset 2001:470:e815::8 (spidey.rellim.com) -1.403 -1.179 -0.191 0.008 0.396 1.426 2.078 0.586 2.605 0.315 0.020 ms -2.42 19.33
Server Offset 204.17.205.1 -551.549 -433.225 -309.434 -7.396 213.297 403.476 457.204 522.731 836.701 166.100 -19.409 µs -5.059 13.57
Server Offset 204.17.205.24 -28.141 -10.462 7.839 60.357 84.962 109.792 192.656 77.123 120.254 23.514 56.748 µs 6.51 18.22
Server Offset 204.17.205.27 -355.201 -77.342 -4.088 34.556 67.653 110.059 297.521 71.741 187.401 33.839 32.325 µs -3.632 39.66
Server Offset SHM(0) -48.002 -20.046 -12.950 -0.981 16.616 39.118 103.504 29.566 59.164 11.865 0.899 µs -1.894 12.61
Temp /dev/sda 45.000 45.000 46.000 49.000 50.000 51.000 53.000 4.000 6.000 1.350 48.370 °C
Temp /dev/sdb 55.000 55.000 57.000 60.000 65.000 68.000 69.000 8.000 13.000 2.413 59.941 °C
Temp /dev/sdc 56.000 56.000 58.000 60.000 61.000 63.000 67.000 3.000 7.000 1.470 59.525 °C
Temp /dev/sdd 62.000 62.000 63.000 66.000 74.000 76.000 77.000 11.000 14.000 2.871 66.680 °C
Temp /dev/sde 44.000 45.000 46.000 48.000 51.000 53.000 54.000 5.000 8.000 1.626 48.276 °C
Temp /dev/sdf 55.000 56.000 57.000 60.000 66.000 69.000 69.000 9.000 13.000 2.553 60.375 °C
Temp LM0 38.750 39.000 40.000 42.000 43.500 43.750 46.000 3.500 4.750 1.163 41.757 °C
Temp LM1 43.500 44.500 44.500 46.500 48.000 48.500 50.000 3.500 4.000 1.117 46.437 °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 45.000 45.000 46.000 49.000 50.000 51.000 53.000 4.000 6.000 1.350 48.369 °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 37.750 38.000 39.000 41.500 43.250 43.250 44.250 4.250 5.250 1.313 41.208 °C
Temp LM16 56.000 56.000 57.000 60.000 66.000 69.000 69.000 9.000 13.000 2.602 60.564 °C
Temp LM17 64.000 64.000 65.000 67.000 69.000 72.000 73.000 4.000 8.000 1.425 67.105 °C
Temp LM18 62.000 62.000 64.000 66.000 74.000 76.000 77.000 10.000 14.000 2.907 66.894 °C
Temp LM19 56.000 56.000 57.000 60.000 65.000 69.000 69.000 8.000 13.000 2.415 60.123 °C
Temp LM2 44.000 45.000 46.000 48.000 51.000 53.000 53.000 5.000 8.000 1.619 48.286 °C
Temp LM20 54.000 57.000 58.000 61.000 64.000 66.000 73.000 6.000 9.000 1.840 61.329 °C
Temp LM21 54.000 57.000 58.000 61.000 64.000 66.000 73.000 6.000 9.000 1.841 61.332 °C
Temp LM22 44.000 46.000 47.000 50.000 52.000 55.000 67.000 5.000 9.000 1.778 49.650 °C
Temp LM23 42.000 44.000 44.000 46.000 49.000 52.000 66.000 5.000 8.000 1.888 46.523 °C
Temp LM24 40.000 41.000 42.000 44.000 46.000 49.000 65.000 4.000 8.000 1.863 43.938 °C
Temp LM3 37.000 37.000 38.000 40.000 41.000 42.000 43.000 3.000 5.000 1.159 39.687 °C
Temp LM4 34.500 34.500 36.000 38.000 40.000 40.000 40.500 4.000 5.500 1.298 38.006 °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 54.500 58.000 59.000 61.000 63.000 65.000 73.500 4.000 7.000 1.567 61.129 °C
Temp LM7 64.000 64.000 65.000 67.000 69.000 72.000 73.000 4.000 8.000 1.408 66.919 °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 55.000 57.000 59.000 61.000 64.000 66.000 73.000 5.000 9.000 1.784 61.397 °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 64.000 64.000 65.000 67.000 69.000 72.000 73.000 4.000 8.000 1.428 67.109 °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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