NTPsec

Pi3/Uputronics

Report generated: Wed Mar 20 19:33:04 2019 UTC
Start Time: Tue Mar 19 19:33:01 2019 UTC
End Time: Wed Mar 20 19:33:01 2019 UTC
Report Period: 1.0 days

Daily stats   Weekly stats   24 Hour scatter plots ( 1  2  3)  

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 -12.401 -6.022 -1.670 -0.307 2.845 5.454 28.275 4.515 11.476 2.355 -0.007 µs 0.7963 43.68
Local Clock Frequency Offset -5.759 -5.735 -5.644 -4.596 -4.214 -4.190 -4.129 1.429 1.545 0.472 -4.763 ppm -1400 1.593e+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 0.123 0.179 0.212 0.322 0.803 1.245 2.111 0.591 1.066 0.209 0.388 µs 6 29

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 0.063 0.099 0.129 0.381 1.741 4.878 12.632 1.612 4.779 0.976 0.609 ppb 6.112 63.43

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 -12.401 -6.022 -1.670 -0.307 2.845 5.454 28.275 4.515 11.476 2.355 -0.007 µs 0.7963 43.68

The clock offsets of the local clock as a histogram.

The Local Clock Offset is field 3 from the loopstats 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) -58.470 -46.655 -33.335 -3.552 35.193 64.679 87.654 68.528 111.334 20.597 -2.452 µs -3.987 10.49

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 74.681 116.361 175.884 307.572 473.722 529.725 608.175 297.838 413.364 88.970 313.865 µs 24.02 85.19

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 204.17.205.16

peer offset 204.17.205.16 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.16 -896.743 -842.508 -822.584 -608.740 -281.562 -243.341 -213.059 541.022 599.167 177.928 -588.700 µs -92.6 452.4

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 204.17.205.17

peer offset 204.17.205.17 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.17 -77.069 -21.726 -14.811 7.162 62.805 72.742 93.389 77.616 94.468 24.703 14.533 µs -0.5828 2.909

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 -76.725 -68.173 -46.258 9.552 44.128 76.801 98.531 90.386 144.974 24.000 6.420 µs -3.104 10.98

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 -93.368 -71.883 -53.252 -0.426 37.895 69.733 99.794 91.147 141.616 27.969 -3.597 µs -5.006 13.99

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 204.17.205.30

peer offset 204.17.205.30 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.30 -64.824 -48.656 -34.536 -5.373 55.107 83.775 102.446 89.643 132.431 24.847 -2.098 µs -2.965 8.031

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) -129.795 -120.435 -113.459 -82.978 4.564 5.909 7.276 118.022 126.344 54.716 -53.810 ms -13.75 40.09

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 SHM(1)

peer offset SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset SHM(1) -12.402 -6.023 -1.671 -0.308 2.846 5.455 28.276 4.517 11.478 2.356 -0.007 µs 0.7936 43.65

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) 2.693 3.779 5.172 12.968 35.885 78.088 1,068.614 30.713 74.309 72.518 20.556 µs 11.47 164.4

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 204.17.205.1

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 16.683 26.635 32.229 72.299 162.512 217.698 308.575 130.283 191.063 41.753 81.750 µs 5.034 16.46

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 204.17.205.16

peer jitter 204.17.205.16 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.16 117.452 124.737 160.404 248.890 392.910 448.853 496.986 232.506 324.116 73.797 258.306 µs 23.73 85.44

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 204.17.205.17

peer jitter 204.17.205.17 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.17 2.284 3.084 5.046 12.403 59.111 71.743 92.678 54.065 68.659 17.845 20.564 µs 1.865 4.988

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 1.676 3.424 4.267 10.920 62.278 83.252 98.606 58.011 79.828 18.043 17.664 µs 2.111 7.154

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 1.964 2.547 4.536 12.715 37.459 55.904 88.537 32.923 53.357 11.306 15.753 µs 3.607 16.63

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 204.17.205.30

peer jitter 204.17.205.30 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.30 3.961 7.373 9.028 19.086 52.864 75.762 92.913 43.836 68.389 14.491 23.602 µs 3.966 14.05

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) 0.162 0.302 0.459 3.148 105.487 110.561 120.617 105.028 110.259 40.656 33.661 ms 0.1625 1.475

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(1)

peer jitter SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(1) 0.048 0.106 0.149 0.320 1.155 3.822 10.997 1.006 3.716 0.654 0.477 µs 6.247 64.58

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 -5.759 -5.735 -5.644 -4.596 -4.214 -4.190 -4.129 1.429 1.545 0.472 -4.763 ppm -1400 1.593e+04
Local Clock Time Offset -12.401 -6.022 -1.670 -0.307 2.845 5.454 28.275 4.515 11.476 2.355 -0.007 µs 0.7963 43.68
Local RMS Frequency Jitter 0.063 0.099 0.129 0.381 1.741 4.878 12.632 1.612 4.779 0.976 0.609 ppb 6.112 63.43
Local RMS Time Jitter 0.123 0.179 0.212 0.322 0.803 1.245 2.111 0.591 1.066 0.209 0.388 µs 6 29
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 2.693 3.779 5.172 12.968 35.885 78.088 1,068.614 30.713 74.309 72.518 20.556 µs 11.47 164.4
Server Jitter 204.17.205.1 16.683 26.635 32.229 72.299 162.512 217.698 308.575 130.283 191.063 41.753 81.750 µs 5.034 16.46
Server Jitter 204.17.205.16 117.452 124.737 160.404 248.890 392.910 448.853 496.986 232.506 324.116 73.797 258.306 µs 23.73 85.44
Server Jitter 204.17.205.17 2.284 3.084 5.046 12.403 59.111 71.743 92.678 54.065 68.659 17.845 20.564 µs 1.865 4.988
Server Jitter 204.17.205.24 1.676 3.424 4.267 10.920 62.278 83.252 98.606 58.011 79.828 18.043 17.664 µs 2.111 7.154
Server Jitter 204.17.205.27 1.964 2.547 4.536 12.715 37.459 55.904 88.537 32.923 53.357 11.306 15.753 µs 3.607 16.63
Server Jitter 204.17.205.30 3.961 7.373 9.028 19.086 52.864 75.762 92.913 43.836 68.389 14.491 23.602 µs 3.966 14.05
Server Jitter SHM(0) 0.162 0.302 0.459 3.148 105.487 110.561 120.617 105.028 110.259 40.656 33.661 ms 0.1625 1.475
Server Jitter SHM(1) 0.048 0.106 0.149 0.320 1.155 3.822 10.997 1.006 3.716 0.654 0.477 µs 6.247 64.58
Server Offset 2001:470:e815::8 (spidey.rellim.com) -58.470 -46.655 -33.335 -3.552 35.193 64.679 87.654 68.528 111.334 20.597 -2.452 µs -3.987 10.49
Server Offset 204.17.205.1 74.681 116.361 175.884 307.572 473.722 529.725 608.175 297.838 413.364 88.970 313.865 µs 24.02 85.19
Server Offset 204.17.205.16 -896.743 -842.508 -822.584 -608.740 -281.562 -243.341 -213.059 541.022 599.167 177.928 -588.700 µs -92.6 452.4
Server Offset 204.17.205.17 -77.069 -21.726 -14.811 7.162 62.805 72.742 93.389 77.616 94.468 24.703 14.533 µs -0.5828 2.909
Server Offset 204.17.205.24 -76.725 -68.173 -46.258 9.552 44.128 76.801 98.531 90.386 144.974 24.000 6.420 µs -3.104 10.98
Server Offset 204.17.205.27 -93.368 -71.883 -53.252 -0.426 37.895 69.733 99.794 91.147 141.616 27.969 -3.597 µs -5.006 13.99
Server Offset 204.17.205.30 -64.824 -48.656 -34.536 -5.373 55.107 83.775 102.446 89.643 132.431 24.847 -2.098 µs -2.965 8.031
Server Offset SHM(0) -129.795 -120.435 -113.459 -82.978 4.564 5.909 7.276 118.022 126.344 54.716 -53.810 ms -13.75 40.09
Server Offset SHM(1) -12.402 -6.023 -1.671 -0.308 2.846 5.455 28.276 4.517 11.478 2.356 -0.007 µs 0.7936 43.65
Summary as CSV file


This server:

CPU: Rasberry Pi 3
OS: Gentoo stable
Kernel: 4.4.26, Config
GPS; Uputronics GPS HAT
GPS/PPS server: gpsd
NTP server: NTPsec
ntp.conf: current

Many thanks to Uputronics for their support and donation of the GPS.

Notes:

20:00 13 Aug 2018 UTC Change poll fro 2 to 3 on PPS
                      poll 2 Local Time Clock Offet Std Dev 1.067
05:00 10 Aug 2018 UTC Change pol from 4 to 2 on PPS
                      4 clearly worse than 1
04:00  9 Aug 2018 UTC Change pol from 1 to 4 on PPS
20:00 20 Oct 2016 UTC SD corruption, rolled back to 27 Sep backup...
19:30 26 Sep 2016 UTC minpoll=mapxpoll=1 on PPS
19:30 26 Sep 2016 UTC maxpoll=minpoll=0 results:
                      Local Clock Freq Offset: 90% 1.01 ppm, Jitter 90% 0.65 us
                      Local Stability 90%: 8.24 ppt
                      PPS Offset  90% 1.55 us, Jitter 90% 0.76 us
22:30 23 Sep 2016 UTC minpoll=mapxpoll=0 on PPS
22:30 23 Sep 2016 UTC maxpoll=minpoll=8 results:
                      Local Clock Freq Offset: 90% 886 ppb, Jitter 90% 39.9 us
                      Local Stability 90%: 6.86 ppt
                      PPS Offset  90% 977 us, Jitter 90% 95.2 us
01:10 22 Sep 2016 UTC minpoll=mapxpoll=8 on PPS
01:10 22 Sep 2016 UTC maxpoll=minpoll=7 results:
                      Local Clock Freq Offset: 90% 1.15ppm, Jitter 90% 1.14 us
                      Local Stability 90%: 1.77 ppt
                      PPS Offset  90% 9.48 us, Jitter 90% 3.45 us
21:50 20 Sep 2016 UTC minpoll=mapxpoll=7 on PPS
21:50 20 Sep 2016 UTC maxpoll=minpoll=5 results:
                      Local Clock Freq Offset: 90% 1.36ppm, Jitter 90% 1.34 us
                      Local Stability 90%: 2.64 ppt
                      PPS Offset  90% 11.4us, Jitter 90% 4.43 us
20:35 19 Sep 2016 UTC minpoll=mapxpoll=5 on PPS
20:35 19 Sep 2016 UTC maxpoll=minpoll=4 results:
                      Local Clock Freq Offset: 90% 1.12ppm, Jitter 90% 1.27 us
                      Local Stability 90%: 2.26 ppt
                      PPS Offset  90% 10.3us, Jitter 90% 4.11 us
19:10 18 Sep 2016 UTC minpoll=mapxpoll=4 on PPS
19:10 18 Sep 2016 UTC maxpoll=minpoll=3 results:
                      Local Clock Freq Offset: 90% 0.5ppm, Jitter 90% 0.18 us
                      Local Stability 90%: 1.9 ppt
                      PPS Offset  90% 3.0us, Jitter 90% 0.56 us
19:25 15 Sep 2016 UTC minpoll=mapxpoll=3 on PPS
19:25 15 Sep 2016 UTC maxpoll=minpoll=2 results:
                      Local Clock Freq Offset: 90% 1.1ppm, Jitter 90% 0.08 us
                      Local Stability 90%: 2.9 ppt
                      PPS Offset  90% 2.2us, Jitter 90% 0.20 us
20:00 13 Sep 2016 UTC minpoll=mapxpoll=2 on PPS
20:00 13 Sep 2016 UTC maxpoll=minpoll=1 results:
                      Local Clock Freq Offset: 90% 1.1ppm, Jitter 90% 0.43 us
                      Local Stability 90%: 2.3 ppt
                      PPS Offset  90% 1.6us, Jitter 90% 0.34 us
18:25 12 Sep 2016 UTC minpoll=mapxpoll=1 on PPS
18:20 12 Sep 2016 UTC maxpoll=minpoll=6 results:
                      Local Clock Freq Offset: 90% 1.4ppm, Jitter 90% 3.3 us
                      Local Stability 90%: 2.2 ppt
                      PPS Offset  90% 68us, Jitter 90% 9.7 us
21:00  9 Sep 2016 UTC minpoll=mapxpoll=6 on PPS
22:15 11 Aug 2016 UTC added prefer to SHM(1)
20:30 26 Jul 2016 UTC git head for gpsd and ntpsec
                      kernel 4.4.14 tto 4.4.15, premption server to low latency
01:24 19 Jul 2016 UTC move GPS fudge 0.108 to 0.1085
19:00 15 Jul 2016 UTC move GPS fudge 0.95 to 0.108
          Use new NTPsec reflock config
18:00  1 Jul 2016 UTC, nice the graph creation
          Note, fewer smaller, spikes in Local Clock Time Offset
00:00 30 Jun 2016 UTC add no_hz=off
          Note decreased Local Clock Time offset
               increased RMS time Jitter

Poll:

      Local Clock      Local Clock  Local Clock    PPS         PPS
Poll  Freq Offset 90%  Jitter 90%   Stability 90%  Offset 90%  Jitter 90%
0          1.0 ppm        0.65µs       8.2 ppt         1.55µs    0.76µs
1          1.1 ppm        0.43µs       2.3 ppt         1.6µs     0.34µs
2          1.1 ppm        0.08µs       2.9 ppt         2.2µs     0.20µs
3          0.5 ppm        0.18µs       1.9 ppt         3.0µs     0.56µs 
4          1.12ppm        1.27µs       2.26ppt        10.3µs     4.11µs 
5          1.36ppm        1.34µs       2.64ppt        11.4µs     4.43µs 
6          1.4 ppm        3.3 µs       2.2 ppt        68. µs     9.7 µs 
7          1.15ppm        1.14µs       1.77ppt         9.4µs     3.45µs
8          0.89ppm       39.9 µs       6.86ppt       977. µs    95.2 µs

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!