NTPsec

Backup/Meinberg

Report generated: Thu Dec 7 15:33:02 2023 UTC
Start Time: Wed Dec 6 15:33:01 2023 UTC
End Time: Thu Dec 7 15:33:01 2023 UTC
Report Period: 1.0 days
Warning: plots clipped

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 -42.832 -40.434 -37.052 2.087 51.856 72.266 78.711 88.908 112.700 25.162 0.496 µs -3.317 7.786
Local Clock Frequency Offset 0.478 0.482 0.496 0.899 1.045 1.060 1.063 0.549 0.579 0.187 0.829 ppm 49.74 200.7

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 0.343 0.418 0.489 1.263 2.489 4.533 5.628 2.000 4.115 0.725 1.322 µs 5.078 21.9

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 0.150 0.188 0.356 0.933 3.256 4.170 4.405 2.900 3.982 0.891 1.251 ppb 2.615 7.493

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 -42.832 -40.434 -37.052 2.087 51.856 72.266 78.711 88.908 112.700 25.162 0.496 µs -3.317 7.786

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 0.478 0.482 0.496 0.899 1.045 1.060 1.063 0.549 0.579 0.187 0.829 ppm 49.74 200.7
Temp /dev/sda 43.000 43.000 43.000 44.000 45.000 45.000 45.000 2.000 2.000 0.695 43.962 °C
Temp /dev/sdb 53.000 53.000 53.000 54.000 55.000 55.000 55.000 2.000 2.000 0.752 54.077 °C
Temp /dev/sdc 54.000 54.000 54.000 56.000 56.000 56.000 58.000 2.000 2.000 0.951 55.352 °C
Temp /dev/sdd 60.000 60.000 60.000 61.000 62.000 62.000 62.000 2.000 2.000 0.755 61.136 °C
Temp /dev/sde 43.000 43.000 43.000 44.000 45.000 45.000 45.000 2.000 2.000 0.762 44.230 °C
Temp /dev/sdf 54.000 54.000 54.000 56.000 56.000 57.000 57.000 2.000 3.000 0.810 55.387 °C
Temp LM0 36.000 36.250 36.250 37.750 38.500 40.000 40.500 2.250 3.750 0.793 37.605 °C
Temp LM1 42.000 42.500 43.000 44.500 45.500 46.000 46.500 2.500 3.500 0.862 44.301 °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 43.000 43.000 43.000 44.000 45.000 45.000 45.000 2.000 2.000 0.698 43.965 °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 34.750 35.000 35.000 36.500 37.750 38.250 38.250 2.750 3.250 0.878 36.498 °C
Temp LM16 54.000 54.000 54.000 56.000 57.000 57.000 57.000 3.000 3.000 0.859 55.523 °C
Temp LM17 61.500 61.500 62.000 63.500 65.000 65.000 65.500 3.000 3.500 1.098 63.613 °C
Temp LM18 60.000 60.000 60.000 61.000 62.000 62.000 62.000 2.000 2.000 0.771 61.254 °C
Temp LM19 53.000 53.000 53.000 54.000 55.000 55.000 55.000 2.000 2.000 0.773 54.174 °C
Temp LM2 43.000 43.000 43.000 44.000 45.000 45.000 45.000 2.000 2.000 0.782 44.261 °C
Temp LM20 55.000 55.000 56.000 57.000 59.000 66.000 67.000 3.000 11.000 1.364 57.620 °C
Temp LM21 55.000 55.000 56.000 57.000 59.000 66.000 67.000 3.000 11.000 1.358 57.620 °C
Temp LM22 43.000 44.000 44.000 46.000 48.000 55.000 59.000 4.000 11.000 1.541 46.355 °C
Temp LM23 40.000 40.000 41.000 43.000 45.000 54.000 58.000 4.000 14.000 1.880 43.181 °C
Temp LM24 38.000 38.000 39.000 41.000 42.000 52.000 57.000 3.000 14.000 1.811 40.645 °C
Temp LM3 34.000 34.000 34.000 36.000 37.000 38.000 38.000 3.000 4.000 0.964 35.850 °C
Temp LM4 31.500 31.500 32.000 33.500 35.000 35.500 35.500 3.000 4.000 1.067 33.585 °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 55.500 56.000 56.000 57.500 58.500 66.000 67.500 2.500 10.000 1.273 57.429 °C
Temp LM7 61.000 61.000 62.000 63.000 65.000 65.000 65.000 3.000 4.000 1.169 63.387 °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 56.000 56.000 58.000 59.000 66.000 68.000 3.000 10.000 1.428 57.676 °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 61.500 61.500 62.000 63.500 65.000 65.000 65.500 3.000 3.500 1.089 63.618 °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) -224.579 -215.073 -175.610 11.222 138.050 147.796 157.403 313.660 362.869 86.260 9.859 µs -4.042 11.09

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 -805.355 -778.148 -700.979 31.448 491.710 557.444 570.346 1,192.689 1,335.592 293.538 4.117 µs -4.638 13.58

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 -38.147 -29.672 -4.836 55.657 107.762 122.043 134.880 112.598 151.715 32.811 53.191 µs 1.854 4.735

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 -219.716 -151.615 -20.199 34.966 83.288 148.044 397.685 103.487 299.659 45.323 33.653 µs -0.1515 20.23

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) -42.833 -40.435 -37.053 2.088 51.857 72.267 78.712 88.910 112.702 25.163 0.496 µs -3.317 7.786

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) 0.948 1.321 2.095 5.132 12.307 19.239 27.781 10.212 17.918 3.410 5.866 µs 4.756 21.39

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 1.588 2.622 4.318 11.420 32.798 66.722 515.673 28.480 64.100 35.841 16.292 µs 10.54 140.4

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 1.527 1.800 2.724 7.635 58.487 72.636 82.842 55.763 70.836 18.560 17.272 µs 1.214 3.506

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 1.291 1.828 3.007 9.131 35.465 96.193 194.726 32.458 94.365 16.723 13.481 µs 5.299 49.03

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) 0.199 0.390 0.677 3.378 10.896 17.542 30.005 10.219 17.152 3.816 4.382 µs 2.833 14.32

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 0.478 0.482 0.496 0.899 1.045 1.060 1.063 0.549 0.579 0.187 0.829 ppm 49.74 200.7
Local Clock Time Offset -42.832 -40.434 -37.052 2.087 51.856 72.266 78.711 88.908 112.700 25.162 0.496 µs -3.317 7.786
Local RMS Frequency Jitter 0.150 0.188 0.356 0.933 3.256 4.170 4.405 2.900 3.982 0.891 1.251 ppb 2.615 7.493
Local RMS Time Jitter 0.343 0.418 0.489 1.263 2.489 4.533 5.628 2.000 4.115 0.725 1.322 µs 5.078 21.9
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.948 1.321 2.095 5.132 12.307 19.239 27.781 10.212 17.918 3.410 5.866 µs 4.756 21.39
Server Jitter 204.17.205.1 1.588 2.622 4.318 11.420 32.798 66.722 515.673 28.480 64.100 35.841 16.292 µs 10.54 140.4
Server Jitter 204.17.205.24 1.527 1.800 2.724 7.635 58.487 72.636 82.842 55.763 70.836 18.560 17.272 µs 1.214 3.506
Server Jitter 204.17.205.27 1.291 1.828 3.007 9.131 35.465 96.193 194.726 32.458 94.365 16.723 13.481 µs 5.299 49.03
Server Jitter SHM(0) 0.199 0.390 0.677 3.378 10.896 17.542 30.005 10.219 17.152 3.816 4.382 µs 2.833 14.32
Server Offset 2001:470:e815::8 (spidey.rellim.com) -224.579 -215.073 -175.610 11.222 138.050 147.796 157.403 313.660 362.869 86.260 9.859 µs -4.042 11.09
Server Offset 204.17.205.1 -805.355 -778.148 -700.979 31.448 491.710 557.444 570.346 1,192.689 1,335.592 293.538 4.117 µs -4.638 13.58
Server Offset 204.17.205.24 -38.147 -29.672 -4.836 55.657 107.762 122.043 134.880 112.598 151.715 32.811 53.191 µs 1.854 4.735
Server Offset 204.17.205.27 -219.716 -151.615 -20.199 34.966 83.288 148.044 397.685 103.487 299.659 45.323 33.653 µs -0.1515 20.23
Server Offset SHM(0) -42.833 -40.435 -37.053 2.088 51.857 72.267 78.712 88.910 112.702 25.163 0.496 µs -3.317 7.786
Temp /dev/sda 43.000 43.000 43.000 44.000 45.000 45.000 45.000 2.000 2.000 0.695 43.962 °C
Temp /dev/sdb 53.000 53.000 53.000 54.000 55.000 55.000 55.000 2.000 2.000 0.752 54.077 °C
Temp /dev/sdc 54.000 54.000 54.000 56.000 56.000 56.000 58.000 2.000 2.000 0.951 55.352 °C
Temp /dev/sdd 60.000 60.000 60.000 61.000 62.000 62.000 62.000 2.000 2.000 0.755 61.136 °C
Temp /dev/sde 43.000 43.000 43.000 44.000 45.000 45.000 45.000 2.000 2.000 0.762 44.230 °C
Temp /dev/sdf 54.000 54.000 54.000 56.000 56.000 57.000 57.000 2.000 3.000 0.810 55.387 °C
Temp LM0 36.000 36.250 36.250 37.750 38.500 40.000 40.500 2.250 3.750 0.793 37.605 °C
Temp LM1 42.000 42.500 43.000 44.500 45.500 46.000 46.500 2.500 3.500 0.862 44.301 °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 43.000 43.000 43.000 44.000 45.000 45.000 45.000 2.000 2.000 0.698 43.965 °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 34.750 35.000 35.000 36.500 37.750 38.250 38.250 2.750 3.250 0.878 36.498 °C
Temp LM16 54.000 54.000 54.000 56.000 57.000 57.000 57.000 3.000 3.000 0.859 55.523 °C
Temp LM17 61.500 61.500 62.000 63.500 65.000 65.000 65.500 3.000 3.500 1.098 63.613 °C
Temp LM18 60.000 60.000 60.000 61.000 62.000 62.000 62.000 2.000 2.000 0.771 61.254 °C
Temp LM19 53.000 53.000 53.000 54.000 55.000 55.000 55.000 2.000 2.000 0.773 54.174 °C
Temp LM2 43.000 43.000 43.000 44.000 45.000 45.000 45.000 2.000 2.000 0.782 44.261 °C
Temp LM20 55.000 55.000 56.000 57.000 59.000 66.000 67.000 3.000 11.000 1.364 57.620 °C
Temp LM21 55.000 55.000 56.000 57.000 59.000 66.000 67.000 3.000 11.000 1.358 57.620 °C
Temp LM22 43.000 44.000 44.000 46.000 48.000 55.000 59.000 4.000 11.000 1.541 46.355 °C
Temp LM23 40.000 40.000 41.000 43.000 45.000 54.000 58.000 4.000 14.000 1.880 43.181 °C
Temp LM24 38.000 38.000 39.000 41.000 42.000 52.000 57.000 3.000 14.000 1.811 40.645 °C
Temp LM3 34.000 34.000 34.000 36.000 37.000 38.000 38.000 3.000 4.000 0.964 35.850 °C
Temp LM4 31.500 31.500 32.000 33.500 35.000 35.500 35.500 3.000 4.000 1.067 33.585 °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 55.500 56.000 56.000 57.500 58.500 66.000 67.500 2.500 10.000 1.273 57.429 °C
Temp LM7 61.000 61.000 62.000 63.000 65.000 65.000 65.000 3.000 4.000 1.169 63.387 °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 56.000 56.000 58.000 59.000 66.000 68.000 3.000 10.000 1.428 57.676 °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 61.500 61.500 62.000 63.500 65.000 65.000 65.500 3.000 3.500 1.089 63.618 °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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