NTPsec

Backup/Meinberg

Report generated: Sat Jul 13 01:33:00 2024 UTC
Start Time: Fri Jul 12 01:33:00 2024 UTC
End Time: Sat Jul 13 01:33:00 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 -11.262 -9.928 -8.946 0.563 13.256 15.251 16.216 22.202 25.179 6.954 1.356 µs -2.755 5.655
Local Clock Frequency Offset 2.803 2.803 2.805 2.926 3.002 3.027 3.035 0.197 0.224 0.070 2.913 ppm 6.797e+04 2.777e+06

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 274.000 295.000 335.000 464.000 628.000 712.000 885.000 293.000 417.000 89.056 470.232 ns 91.8 458.5

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 42.000 53.000 76.000 378.000 800.000 930.000 953.000 724.000 877.000 210.429 377.941 10e-12 3.388 8.633

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 -11.262 -9.928 -8.946 0.563 13.256 15.251 16.216 22.202 25.179 6.954 1.356 µs -2.755 5.655

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 2.803 2.803 2.805 2.926 3.002 3.027 3.035 0.197 0.224 0.070 2.913 ppm 6.797e+04 2.777e+06
Temp /dev/sda 49.000 49.000 49.000 49.000 50.000 50.000 50.000 1.000 1.000 0.468 49.325 °C
Temp /dev/sdb 59.000 59.000 60.000 60.000 61.000 61.000 61.000 1.000 2.000 0.449 60.199 °C
Temp /dev/sdc 60.000 60.000 60.000 60.000 61.000 61.000 61.000 1.000 1.000 0.405 60.206 °C
Temp /dev/sdd 66.000 66.000 66.000 67.000 68.000 68.000 68.000 2.000 2.000 0.741 67.003 °C
Temp /dev/sde 48.000 48.000 48.000 49.000 50.000 50.000 50.000 2.000 2.000 0.545 49.196 °C
Temp /dev/sdf 60.000 60.000 60.000 62.000 63.000 63.000 63.000 3.000 3.000 0.732 61.622 °C
Temp LM0 42.000 42.000 42.000 42.750 43.250 43.500 43.750 1.250 1.500 0.405 42.694 °C
Temp LM1 46.000 46.500 46.500 47.500 48.000 48.000 48.500 1.500 1.500 0.490 47.346 °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 49.000 49.000 49.000 49.000 50.000 50.000 50.000 1.000 1.000 0.468 49.325 °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 41.500 41.500 41.500 42.500 43.000 43.250 43.500 1.500 1.750 0.482 42.323 °C
Temp LM16 60.000 61.000 61.000 62.000 63.000 63.000 63.000 2.000 2.000 0.721 61.937 °C
Temp LM17 67.000 67.000 67.000 68.000 68.500 69.000 69.000 1.500 2.000 0.621 67.876 °C
Temp LM18 66.000 66.000 67.000 67.000 68.000 68.000 68.000 1.000 2.000 0.553 67.311 °C
Temp LM19 60.000 60.000 60.000 60.000 61.000 61.000 61.000 1.000 1.000 0.471 60.332 °C
Temp LM2 48.000 48.000 49.000 49.000 50.000 50.000 50.000 1.000 2.000 0.517 49.217 °C
Temp LM20 59.000 60.000 61.000 62.000 64.000 65.000 65.000 3.000 5.000 1.039 62.003 °C
Temp LM21 59.000 60.000 60.000 62.000 64.000 65.000 65.000 4.000 5.000 1.058 61.993 °C
Temp LM22 48.000 48.000 49.000 50.000 52.000 52.000 52.000 3.000 4.000 0.861 50.252 °C
Temp LM23 45.000 45.000 46.000 47.000 48.000 48.000 49.000 2.000 3.000 0.816 46.713 °C
Temp LM24 42.000 43.000 44.000 45.000 46.000 47.000 48.000 2.000 4.000 0.882 44.829 °C
Temp LM3 40.000 40.000 40.000 41.000 41.000 41.000 42.000 1.000 1.000 0.509 40.573 °C
Temp LM4 38.000 38.500 38.500 39.000 40.000 40.000 40.000 1.500 1.500 0.476 39.103 °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 60.500 60.500 61.000 61.500 62.500 63.000 63.000 1.500 2.500 0.617 61.745 °C
Temp LM7 67.000 67.000 67.000 68.000 68.000 69.000 69.000 1.000 2.000 0.514 67.580 °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 57.000 60.000 61.000 62.000 64.000 64.000 65.000 3.000 4.000 1.059 61.997 °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 67.000 67.000 67.000 68.000 68.500 69.000 69.000 1.500 2.000 0.619 67.871 °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) -132.071 -126.146 -115.739 18.152 152.689 158.165 165.965 268.428 284.311 66.451 16.522 µs -2.759 7.085

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 -194.906 -190.869 -179.931 -10.712 134.493 147.473 157.832 314.424 338.342 89.378 -4.516 µs -4.572 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 204.17.205.24

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 -26.772 -8.923 6.637 60.746 78.639 84.965 95.148 72.002 93.888 20.387 55.766 µs 8.906 21.84

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 -25.539 -14.067 0.480 33.915 58.219 66.469 82.578 57.739 80.536 17.352 32.481 µs 2.808 6.682

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) -11.263 -9.929 -8.947 0.564 13.257 15.252 16.217 22.204 25.181 6.955 1.356 µs -2.756 5.656

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) 0.615 0.881 1.590 4.442 9.885 12.744 17.263 8.295 11.863 2.541 4.930 µs 4.71 14.46

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 1.059 1.494 2.209 7.821 19.592 24.512 33.770 17.383 23.018 5.481 8.938 µs 3.068 8.52

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 0.675 1.783 2.514 6.950 54.530 72.138 81.877 52.016 70.355 16.466 13.742 µs 1.66 5.661

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 0.861 1.104 2.276 7.206 20.929 26.904 101.627 18.653 25.800 7.804 9.096 µs 5.781 60.64

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) 0.133 0.215 0.293 0.856 2.482 3.164 4.205 2.189 2.949 0.694 1.054 µs 2.927 8.513

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 2.803 2.803 2.805 2.926 3.002 3.027 3.035 0.197 0.224 0.070 2.913 ppm 6.797e+04 2.777e+06
Local Clock Time Offset -11.262 -9.928 -8.946 0.563 13.256 15.251 16.216 22.202 25.179 6.954 1.356 µs -2.755 5.655
Local RMS Frequency Jitter 42.000 53.000 76.000 378.000 800.000 930.000 953.000 724.000 877.000 210.429 377.941 10e-12 3.388 8.633
Local RMS Time Jitter 274.000 295.000 335.000 464.000 628.000 712.000 885.000 293.000 417.000 89.056 470.232 ns 91.8 458.5
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.615 0.881 1.590 4.442 9.885 12.744 17.263 8.295 11.863 2.541 4.930 µs 4.71 14.46
Server Jitter 204.17.205.1 1.059 1.494 2.209 7.821 19.592 24.512 33.770 17.383 23.018 5.481 8.938 µs 3.068 8.52
Server Jitter 204.17.205.24 0.675 1.783 2.514 6.950 54.530 72.138 81.877 52.016 70.355 16.466 13.742 µs 1.66 5.661
Server Jitter 204.17.205.27 0.861 1.104 2.276 7.206 20.929 26.904 101.627 18.653 25.800 7.804 9.096 µs 5.781 60.64
Server Jitter SHM(0) 0.133 0.215 0.293 0.856 2.482 3.164 4.205 2.189 2.949 0.694 1.054 µs 2.927 8.513
Server Offset 2001:470:e815::8 (spidey.rellim.com) -132.071 -126.146 -115.739 18.152 152.689 158.165 165.965 268.428 284.311 66.451 16.522 µs -2.759 7.085
Server Offset 204.17.205.1 -194.906 -190.869 -179.931 -10.712 134.493 147.473 157.832 314.424 338.342 89.378 -4.516 µs -4.572 11.54
Server Offset 204.17.205.24 -26.772 -8.923 6.637 60.746 78.639 84.965 95.148 72.002 93.888 20.387 55.766 µs 8.906 21.84
Server Offset 204.17.205.27 -25.539 -14.067 0.480 33.915 58.219 66.469 82.578 57.739 80.536 17.352 32.481 µs 2.808 6.682
Server Offset SHM(0) -11.263 -9.929 -8.947 0.564 13.257 15.252 16.217 22.204 25.181 6.955 1.356 µs -2.756 5.656
Temp /dev/sda 49.000 49.000 49.000 49.000 50.000 50.000 50.000 1.000 1.000 0.468 49.325 °C
Temp /dev/sdb 59.000 59.000 60.000 60.000 61.000 61.000 61.000 1.000 2.000 0.449 60.199 °C
Temp /dev/sdc 60.000 60.000 60.000 60.000 61.000 61.000 61.000 1.000 1.000 0.405 60.206 °C
Temp /dev/sdd 66.000 66.000 66.000 67.000 68.000 68.000 68.000 2.000 2.000 0.741 67.003 °C
Temp /dev/sde 48.000 48.000 48.000 49.000 50.000 50.000 50.000 2.000 2.000 0.545 49.196 °C
Temp /dev/sdf 60.000 60.000 60.000 62.000 63.000 63.000 63.000 3.000 3.000 0.732 61.622 °C
Temp LM0 42.000 42.000 42.000 42.750 43.250 43.500 43.750 1.250 1.500 0.405 42.694 °C
Temp LM1 46.000 46.500 46.500 47.500 48.000 48.000 48.500 1.500 1.500 0.490 47.346 °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 49.000 49.000 49.000 49.000 50.000 50.000 50.000 1.000 1.000 0.468 49.325 °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 41.500 41.500 41.500 42.500 43.000 43.250 43.500 1.500 1.750 0.482 42.323 °C
Temp LM16 60.000 61.000 61.000 62.000 63.000 63.000 63.000 2.000 2.000 0.721 61.937 °C
Temp LM17 67.000 67.000 67.000 68.000 68.500 69.000 69.000 1.500 2.000 0.621 67.876 °C
Temp LM18 66.000 66.000 67.000 67.000 68.000 68.000 68.000 1.000 2.000 0.553 67.311 °C
Temp LM19 60.000 60.000 60.000 60.000 61.000 61.000 61.000 1.000 1.000 0.471 60.332 °C
Temp LM2 48.000 48.000 49.000 49.000 50.000 50.000 50.000 1.000 2.000 0.517 49.217 °C
Temp LM20 59.000 60.000 61.000 62.000 64.000 65.000 65.000 3.000 5.000 1.039 62.003 °C
Temp LM21 59.000 60.000 60.000 62.000 64.000 65.000 65.000 4.000 5.000 1.058 61.993 °C
Temp LM22 48.000 48.000 49.000 50.000 52.000 52.000 52.000 3.000 4.000 0.861 50.252 °C
Temp LM23 45.000 45.000 46.000 47.000 48.000 48.000 49.000 2.000 3.000 0.816 46.713 °C
Temp LM24 42.000 43.000 44.000 45.000 46.000 47.000 48.000 2.000 4.000 0.882 44.829 °C
Temp LM3 40.000 40.000 40.000 41.000 41.000 41.000 42.000 1.000 1.000 0.509 40.573 °C
Temp LM4 38.000 38.500 38.500 39.000 40.000 40.000 40.000 1.500 1.500 0.476 39.103 °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 60.500 60.500 61.000 61.500 62.500 63.000 63.000 1.500 2.500 0.617 61.745 °C
Temp LM7 67.000 67.000 67.000 68.000 68.000 69.000 69.000 1.000 2.000 0.514 67.580 °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 57.000 60.000 61.000 62.000 64.000 64.000 65.000 3.000 4.000 1.059 61.997 °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 67.000 67.000 67.000 68.000 68.500 69.000 69.000 1.500 2.000 0.619 67.871 °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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