NTPsec

Backup/Meinberg

Report generated: Thu Apr 25 15:43:01 2024 UTC
Start Time: Thu Apr 18 15:43:00 2024 UTC
End Time: Thu Apr 25 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 -74.894 -30.859 -17.567 -4.194 40.982 53.953 120.496 58.549 84.812 18.073 0.254 µs -2.408 9.147
Local Clock Frequency Offset 6.744 6.758 6.821 7.066 7.230 7.352 7.436 0.409 0.594 0.119 7.052 ppm 1.968e+05 1.145e+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 0.248 0.346 0.404 0.619 2.276 4.698 11.489 1.872 4.352 0.866 0.885 µs 5.056 38.91

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 0.047 0.072 0.129 0.555 2.627 3.501 6.632 2.498 3.429 0.779 0.779 ppb 2.53 11.31

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 -74.894 -30.859 -17.567 -4.194 40.982 53.953 120.496 58.549 84.812 18.073 0.254 µs -2.408 9.147

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 6.744 6.758 6.821 7.066 7.230 7.352 7.436 0.409 0.594 0.119 7.052 ppm 1.968e+05 1.145e+07
Temp /dev/sda 41.000 41.000 41.000 42.000 44.000 45.000 48.000 3.000 4.000 0.835 42.284 °C
Temp /dev/sdb 51.000 51.000 52.000 53.000 60.000 60.000 61.000 8.000 9.000 2.183 53.745 °C
Temp /dev/sdc 51.000 51.000 53.000 53.000 56.000 56.000 60.000 3.000 5.000 0.926 53.159 °C
Temp /dev/sdd 57.000 57.000 58.000 60.000 68.000 69.000 69.000 10.000 12.000 2.694 60.507 °C
Temp /dev/sde 40.000 40.000 41.000 42.000 45.000 46.000 46.000 4.000 6.000 1.170 42.032 °C
Temp /dev/sdf 51.000 51.000 52.000 53.000 60.000 61.000 62.000 8.000 10.000 2.310 54.024 °C
Temp LM0 35.500 35.750 36.000 37.000 37.750 38.250 40.250 1.750 2.500 0.496 37.010 °C
Temp LM1 40.000 40.500 40.500 42.000 42.500 43.000 45.000 2.000 2.500 0.540 41.753 °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 44.000 45.000 48.000 3.000 4.000 0.835 42.284 °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 34.000 34.500 34.750 35.750 36.500 37.000 37.750 1.750 2.500 0.546 35.816 °C
Temp LM16 51.000 51.000 52.000 53.000 61.000 62.000 62.000 9.000 11.000 2.327 54.143 °C
Temp LM17 59.500 60.000 60.000 61.500 62.500 65.500 66.000 2.500 5.500 0.984 61.485 °C
Temp LM18 57.000 58.000 58.000 60.000 68.000 69.000 69.000 10.000 11.000 2.712 60.650 °C
Temp LM19 51.000 51.000 52.000 53.000 60.000 60.000 61.000 8.000 9.000 2.181 53.828 °C
Temp LM2 40.000 40.000 41.000 42.000 45.000 46.000 46.000 4.000 6.000 1.183 42.028 °C
Temp LM20 53.000 54.000 54.000 56.000 57.000 59.000 71.000 3.000 5.000 1.262 55.734 °C
Temp LM21 53.000 54.000 54.000 56.000 57.000 59.000 70.000 3.000 5.000 1.257 55.729 °C
Temp LM22 41.000 42.000 43.000 44.000 46.000 48.000 65.000 3.000 6.000 1.455 44.042 °C
Temp LM23 39.000 40.000 40.000 42.000 44.000 46.000 62.000 4.000 6.000 1.477 41.922 °C
Temp LM24 37.000 38.000 39.000 40.000 42.000 44.000 60.000 3.000 6.000 1.436 39.980 °C
Temp LM3 33.000 33.000 33.000 34.000 35.000 35.000 37.000 2.000 2.000 0.642 34.196 °C
Temp LM4 30.000 30.000 30.500 32.000 32.500 33.000 33.500 2.000 3.000 0.615 31.793 °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 53.500 54.000 54.500 55.500 57.000 58.500 70.000 2.500 4.500 1.053 55.508 °C
Temp LM7 59.000 60.000 60.000 61.000 62.000 65.000 66.000 2.000 5.000 0.964 61.268 °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 53.000 53.000 54.000 56.000 58.000 59.000 71.000 4.000 6.000 1.314 55.754 °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 59.500 60.000 60.000 61.500 62.500 65.500 66.000 2.500 5.500 0.988 61.485 °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) -726.161 -368.585 -212.634 11.586 119.723 658.463 887.502 332.357 1,027.048 141.578 3.714 µs -2.831 19.24

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 -851.627 -749.370 -527.074 37.368 290.339 428.600 535.250 817.413 1,177.970 238.456 -11.097 µs -5.357 16.62

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 -1,988.911 -24.697 1.139 57.153 97.381 127.110 938.543 96.242 151.807 45.433 55.819 µs -18.78 1005

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 -524.162 -103.747 -6.306 34.765 70.544 147.764 369.524 76.850 251.511 40.963 33.198 µs -2.218 38.44

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 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) -74.895 -30.860 -17.568 -4.195 40.983 53.954 120.497 58.551 84.814 18.074 0.254 µs -2.408 9.147

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) 0.532 1.104 1.770 4.997 13.663 27.561 75.320 11.893 26.457 5.330 6.160 µs 5.391 46.1

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 1.110 2.159 3.423 9.681 27.125 42.226 106.932 23.702 40.067 8.727 12.067 µs 3.952 23.69

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 0.009 0.055 0.078 36.863 0.052 0.076 0.991 0.046 ms 30.07 1043

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 1.562 2.352 7.619 26.061 68.993 165.592 23.709 67.431 12.194 10.792 µs 4.909 41.04

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) 0.085 0.267 0.419 1.495 8.088 18.254 64.867 7.669 17.987 3.738 2.507 µs 5.506 60.96

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 6.744 6.758 6.821 7.066 7.230 7.352 7.436 0.409 0.594 0.119 7.052 ppm 1.968e+05 1.145e+07
Local Clock Time Offset -74.894 -30.859 -17.567 -4.194 40.982 53.953 120.496 58.549 84.812 18.073 0.254 µs -2.408 9.147
Local RMS Frequency Jitter 0.047 0.072 0.129 0.555 2.627 3.501 6.632 2.498 3.429 0.779 0.779 ppb 2.53 11.31
Local RMS Time Jitter 0.248 0.346 0.404 0.619 2.276 4.698 11.489 1.872 4.352 0.866 0.885 µs 5.056 38.91
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.532 1.104 1.770 4.997 13.663 27.561 75.320 11.893 26.457 5.330 6.160 µs 5.391 46.1
Server Jitter 204.17.205.1 1.110 2.159 3.423 9.681 27.125 42.226 106.932 23.702 40.067 8.727 12.067 µs 3.952 23.69
Server Jitter 204.17.205.24 0.001 0.002 0.003 0.009 0.055 0.078 36.863 0.052 0.076 0.991 0.046 ms 30.07 1043
Server Jitter 204.17.205.27 0.000 1.562 2.352 7.619 26.061 68.993 165.592 23.709 67.431 12.194 10.792 µs 4.909 41.04
Server Jitter SHM(0) 0.085 0.267 0.419 1.495 8.088 18.254 64.867 7.669 17.987 3.738 2.507 µs 5.506 60.96
Server Offset 2001:470:e815::8 (spidey.rellim.com) -726.161 -368.585 -212.634 11.586 119.723 658.463 887.502 332.357 1,027.048 141.578 3.714 µs -2.831 19.24
Server Offset 204.17.205.1 -851.627 -749.370 -527.074 37.368 290.339 428.600 535.250 817.413 1,177.970 238.456 -11.097 µs -5.357 16.62
Server Offset 204.17.205.24 -1,988.911 -24.697 1.139 57.153 97.381 127.110 938.543 96.242 151.807 45.433 55.819 µs -18.78 1005
Server Offset 204.17.205.27 -524.162 -103.747 -6.306 34.765 70.544 147.764 369.524 76.850 251.511 40.963 33.198 µs -2.218 38.44
Server Offset SHM(0) -74.895 -30.860 -17.568 -4.195 40.983 53.954 120.497 58.551 84.814 18.074 0.254 µs -2.408 9.147
Temp /dev/sda 41.000 41.000 41.000 42.000 44.000 45.000 48.000 3.000 4.000 0.835 42.284 °C
Temp /dev/sdb 51.000 51.000 52.000 53.000 60.000 60.000 61.000 8.000 9.000 2.183 53.745 °C
Temp /dev/sdc 51.000 51.000 53.000 53.000 56.000 56.000 60.000 3.000 5.000 0.926 53.159 °C
Temp /dev/sdd 57.000 57.000 58.000 60.000 68.000 69.000 69.000 10.000 12.000 2.694 60.507 °C
Temp /dev/sde 40.000 40.000 41.000 42.000 45.000 46.000 46.000 4.000 6.000 1.170 42.032 °C
Temp /dev/sdf 51.000 51.000 52.000 53.000 60.000 61.000 62.000 8.000 10.000 2.310 54.024 °C
Temp LM0 35.500 35.750 36.000 37.000 37.750 38.250 40.250 1.750 2.500 0.496 37.010 °C
Temp LM1 40.000 40.500 40.500 42.000 42.500 43.000 45.000 2.000 2.500 0.540 41.753 °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 44.000 45.000 48.000 3.000 4.000 0.835 42.284 °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 34.000 34.500 34.750 35.750 36.500 37.000 37.750 1.750 2.500 0.546 35.816 °C
Temp LM16 51.000 51.000 52.000 53.000 61.000 62.000 62.000 9.000 11.000 2.327 54.143 °C
Temp LM17 59.500 60.000 60.000 61.500 62.500 65.500 66.000 2.500 5.500 0.984 61.485 °C
Temp LM18 57.000 58.000 58.000 60.000 68.000 69.000 69.000 10.000 11.000 2.712 60.650 °C
Temp LM19 51.000 51.000 52.000 53.000 60.000 60.000 61.000 8.000 9.000 2.181 53.828 °C
Temp LM2 40.000 40.000 41.000 42.000 45.000 46.000 46.000 4.000 6.000 1.183 42.028 °C
Temp LM20 53.000 54.000 54.000 56.000 57.000 59.000 71.000 3.000 5.000 1.262 55.734 °C
Temp LM21 53.000 54.000 54.000 56.000 57.000 59.000 70.000 3.000 5.000 1.257 55.729 °C
Temp LM22 41.000 42.000 43.000 44.000 46.000 48.000 65.000 3.000 6.000 1.455 44.042 °C
Temp LM23 39.000 40.000 40.000 42.000 44.000 46.000 62.000 4.000 6.000 1.477 41.922 °C
Temp LM24 37.000 38.000 39.000 40.000 42.000 44.000 60.000 3.000 6.000 1.436 39.980 °C
Temp LM3 33.000 33.000 33.000 34.000 35.000 35.000 37.000 2.000 2.000 0.642 34.196 °C
Temp LM4 30.000 30.000 30.500 32.000 32.500 33.000 33.500 2.000 3.000 0.615 31.793 °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 53.500 54.000 54.500 55.500 57.000 58.500 70.000 2.500 4.500 1.053 55.508 °C
Temp LM7 59.000 60.000 60.000 61.000 62.000 65.000 66.000 2.000 5.000 0.964 61.268 °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 53.000 53.000 54.000 56.000 58.000 59.000 71.000 4.000 6.000 1.314 55.754 °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 59.500 60.000 60.000 61.500 62.500 65.500 66.000 2.500 5.500 0.988 61.485 °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.



This page autogenerated by ntpviz, part of the NTPsec project
html 5    Valid CSS!