NTPsec

Backup/Meinberg

Report generated: Wed Apr 24 23:33:00 2024 UTC
Start Time: Tue Apr 23 23:33:00 2024 UTC
End Time: Wed Apr 24 23:33:00 2024 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 -14.945 -14.067 -12.615 -3.842 37.547 54.977 58.392 50.162 69.044 14.393 0.453 µs -1.728 6.089
Local Clock Frequency Offset 6.914 6.917 6.943 7.136 7.221 7.224 7.225 0.277 0.307 0.082 7.121 ppm 6.3e+05 5.402e+07

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 0.313 0.367 0.408 0.576 1.816 3.526 4.188 1.408 3.159 0.530 0.729 µs 4.908 25

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 0.055 0.069 0.096 0.527 2.328 3.273 3.423 2.232 3.204 0.610 0.633 ppb 3.045 12.28

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 -14.945 -14.067 -12.615 -3.842 37.547 54.977 58.392 50.162 69.044 14.393 0.453 µs -1.728 6.089

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 6.914 6.917 6.943 7.136 7.221 7.224 7.225 0.277 0.307 0.082 7.121 ppm 6.3e+05 5.402e+07
Temp /dev/sda 41.000 41.000 41.000 42.000 43.000 43.000 43.000 2.000 2.000 0.572 42.332 °C
Temp /dev/sdb 52.000 52.000 52.000 53.000 54.000 54.000 54.000 2.000 2.000 0.564 52.990 °C
Temp /dev/sdc 53.000 53.000 53.000 53.000 53.000 54.000 54.000 0.000 1.000 0.102 53.010 °C
Temp /dev/sdd 58.000 58.000 59.000 60.000 62.000 62.000 62.000 3.000 4.000 0.870 59.808 °C
Temp /dev/sde 41.000 41.000 41.000 42.000 42.000 43.000 43.000 1.000 2.000 0.413 41.878 °C
Temp /dev/sdf 52.000 52.000 52.000 54.000 55.000 55.000 55.000 3.000 3.000 1.006 53.766 °C
Temp LM0 36.500 36.500 36.750 37.250 37.750 38.000 38.500 1.000 1.500 0.332 37.260 °C
Temp LM1 41.000 41.000 41.500 42.000 42.500 43.000 43.500 1.000 2.000 0.399 42.042 °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 41.000 41.000 42.000 43.000 43.000 43.000 2.000 2.000 0.572 42.332 °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 35.000 35.000 35.250 36.250 36.500 36.750 37.000 1.250 1.750 0.405 36.107 °C
Temp LM16 52.000 52.000 52.000 54.000 55.000 55.000 55.000 3.000 3.000 1.057 53.934 °C
Temp LM17 60.500 60.500 61.000 62.000 62.500 62.500 62.500 1.500 2.000 0.582 61.788 °C
Temp LM18 58.000 58.000 59.000 60.000 62.000 62.000 62.000 3.000 4.000 0.905 59.948 °C
Temp LM19 52.000 52.000 52.000 53.000 54.000 54.000 54.000 2.000 2.000 0.560 53.028 °C
Temp LM2 41.000 41.000 41.000 42.000 42.000 43.000 43.000 1.000 2.000 0.413 41.878 °C
Temp LM20 53.000 54.000 55.000 56.000 57.000 58.000 61.000 2.000 4.000 0.945 55.965 °C
Temp LM21 53.000 54.000 55.000 56.000 57.000 58.000 61.000 2.000 4.000 0.956 55.965 °C
Temp LM22 42.000 43.000 43.000 44.000 46.000 47.000 54.000 3.000 4.000 1.040 44.381 °C
Temp LM23 40.000 40.000 41.000 42.000 43.000 45.000 50.000 2.000 5.000 0.998 41.794 °C
Temp LM24 38.000 39.000 39.000 40.000 41.000 42.000 49.000 2.000 3.000 0.998 40.087 °C
Temp LM3 34.000 34.000 34.000 35.000 35.000 35.000 36.000 1.000 1.000 0.494 34.612 °C
Temp LM4 31.000 31.000 31.000 32.000 32.500 33.000 33.000 1.500 2.000 0.470 32.098 °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 54.500 55.000 55.500 56.500 57.000 63.000 1.500 2.500 0.666 55.736 °C
Temp LM7 60.000 60.000 61.000 62.000 62.000 62.000 62.000 1.000 2.000 0.572 61.503 °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 54.000 54.000 54.000 56.000 58.000 59.000 63.000 4.000 5.000 1.047 56.066 °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 60.500 60.500 61.000 62.000 62.500 62.500 62.500 1.500 2.000 0.589 61.794 °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) -342.200 -322.832 -142.553 -10.718 71.044 98.810 103.301 213.597 421.642 72.244 -13.348 µs -7.327 29.83

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 -453.642 -432.966 -343.765 -22.915 224.321 243.925 253.121 568.086 676.891 190.344 -17.059 µs -4.917 12.09

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 204.17.205.24

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 -67.602 -17.580 -0.770 56.730 98.813 111.989 143.101 99.583 129.569 25.989 55.359 µs 4.157 11.54

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 -301.356 -154.794 -7.316 35.793 83.673 207.004 317.860 90.989 361.798 49.170 35.054 µs -1.592 21.7

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) -14.946 -14.068 -12.616 -3.843 37.548 54.978 58.393 50.164 69.046 14.394 0.453 µs -1.728 6.089

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) 0.780 1.019 1.638 4.776 12.175 27.427 39.589 10.537 26.408 4.259 5.653 µs 4.415 26.1

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 1.386 2.581 3.437 8.781 24.383 32.633 45.837 20.946 30.052 6.899 10.785 µs 3.359 11.1

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 1.241 1.708 2.794 6.992 56.383 75.029 222.379 53.589 73.321 23.463 15.341 µs 3.983 33.77

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 0.000 1.339 2.353 7.566 37.458 90.786 161.205 35.105 89.447 16.339 12.498 µs 3.659 24.43

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) 0.085 0.228 0.418 1.241 6.362 15.331 23.888 5.944 15.103 2.585 1.953 µs 3.538 21.31

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 6.914 6.917 6.943 7.136 7.221 7.224 7.225 0.277 0.307 0.082 7.121 ppm 6.3e+05 5.402e+07
Local Clock Time Offset -14.945 -14.067 -12.615 -3.842 37.547 54.977 58.392 50.162 69.044 14.393 0.453 µs -1.728 6.089
Local RMS Frequency Jitter 0.055 0.069 0.096 0.527 2.328 3.273 3.423 2.232 3.204 0.610 0.633 ppb 3.045 12.28
Local RMS Time Jitter 0.313 0.367 0.408 0.576 1.816 3.526 4.188 1.408 3.159 0.530 0.729 µs 4.908 25
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.780 1.019 1.638 4.776 12.175 27.427 39.589 10.537 26.408 4.259 5.653 µs 4.415 26.1
Server Jitter 204.17.205.1 1.386 2.581 3.437 8.781 24.383 32.633 45.837 20.946 30.052 6.899 10.785 µs 3.359 11.1
Server Jitter 204.17.205.24 1.241 1.708 2.794 6.992 56.383 75.029 222.379 53.589 73.321 23.463 15.341 µs 3.983 33.77
Server Jitter 204.17.205.27 0.000 1.339 2.353 7.566 37.458 90.786 161.205 35.105 89.447 16.339 12.498 µs 3.659 24.43
Server Jitter SHM(0) 0.085 0.228 0.418 1.241 6.362 15.331 23.888 5.944 15.103 2.585 1.953 µs 3.538 21.31
Server Offset 2001:470:e815::8 (spidey.rellim.com) -342.200 -322.832 -142.553 -10.718 71.044 98.810 103.301 213.597 421.642 72.244 -13.348 µs -7.327 29.83
Server Offset 204.17.205.1 -453.642 -432.966 -343.765 -22.915 224.321 243.925 253.121 568.086 676.891 190.344 -17.059 µs -4.917 12.09
Server Offset 204.17.205.24 -67.602 -17.580 -0.770 56.730 98.813 111.989 143.101 99.583 129.569 25.989 55.359 µs 4.157 11.54
Server Offset 204.17.205.27 -301.356 -154.794 -7.316 35.793 83.673 207.004 317.860 90.989 361.798 49.170 35.054 µs -1.592 21.7
Server Offset SHM(0) -14.946 -14.068 -12.616 -3.843 37.548 54.978 58.393 50.164 69.046 14.394 0.453 µs -1.728 6.089
Temp /dev/sda 41.000 41.000 41.000 42.000 43.000 43.000 43.000 2.000 2.000 0.572 42.332 °C
Temp /dev/sdb 52.000 52.000 52.000 53.000 54.000 54.000 54.000 2.000 2.000 0.564 52.990 °C
Temp /dev/sdc 53.000 53.000 53.000 53.000 53.000 54.000 54.000 0.000 1.000 0.102 53.010 °C
Temp /dev/sdd 58.000 58.000 59.000 60.000 62.000 62.000 62.000 3.000 4.000 0.870 59.808 °C
Temp /dev/sde 41.000 41.000 41.000 42.000 42.000 43.000 43.000 1.000 2.000 0.413 41.878 °C
Temp /dev/sdf 52.000 52.000 52.000 54.000 55.000 55.000 55.000 3.000 3.000 1.006 53.766 °C
Temp LM0 36.500 36.500 36.750 37.250 37.750 38.000 38.500 1.000 1.500 0.332 37.260 °C
Temp LM1 41.000 41.000 41.500 42.000 42.500 43.000 43.500 1.000 2.000 0.399 42.042 °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 41.000 41.000 42.000 43.000 43.000 43.000 2.000 2.000 0.572 42.332 °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 35.000 35.000 35.250 36.250 36.500 36.750 37.000 1.250 1.750 0.405 36.107 °C
Temp LM16 52.000 52.000 52.000 54.000 55.000 55.000 55.000 3.000 3.000 1.057 53.934 °C
Temp LM17 60.500 60.500 61.000 62.000 62.500 62.500 62.500 1.500 2.000 0.582 61.788 °C
Temp LM18 58.000 58.000 59.000 60.000 62.000 62.000 62.000 3.000 4.000 0.905 59.948 °C
Temp LM19 52.000 52.000 52.000 53.000 54.000 54.000 54.000 2.000 2.000 0.560 53.028 °C
Temp LM2 41.000 41.000 41.000 42.000 42.000 43.000 43.000 1.000 2.000 0.413 41.878 °C
Temp LM20 53.000 54.000 55.000 56.000 57.000 58.000 61.000 2.000 4.000 0.945 55.965 °C
Temp LM21 53.000 54.000 55.000 56.000 57.000 58.000 61.000 2.000 4.000 0.956 55.965 °C
Temp LM22 42.000 43.000 43.000 44.000 46.000 47.000 54.000 3.000 4.000 1.040 44.381 °C
Temp LM23 40.000 40.000 41.000 42.000 43.000 45.000 50.000 2.000 5.000 0.998 41.794 °C
Temp LM24 38.000 39.000 39.000 40.000 41.000 42.000 49.000 2.000 3.000 0.998 40.087 °C
Temp LM3 34.000 34.000 34.000 35.000 35.000 35.000 36.000 1.000 1.000 0.494 34.612 °C
Temp LM4 31.000 31.000 31.000 32.000 32.500 33.000 33.000 1.500 2.000 0.470 32.098 °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 54.500 55.000 55.500 56.500 57.000 63.000 1.500 2.500 0.666 55.736 °C
Temp LM7 60.000 60.000 61.000 62.000 62.000 62.000 62.000 1.000 2.000 0.572 61.503 °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 54.000 54.000 54.000 56.000 58.000 59.000 63.000 4.000 5.000 1.047 56.066 °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 60.500 60.500 61.000 62.000 62.500 62.500 62.500 1.500 2.000 0.589 61.794 °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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