NTPsec

Backup/Meinberg

Report generated: Wed Sep 27 10:33:01 2023 UTC
Start Time: Tue Sep 26 10:33:01 2023 UTC
End Time: Wed Sep 27 10:33:01 2023 UTC
Report Period: 1.0 days
Warning: plots clipped

Daily stats   Weekly stats  

Local Clock Time/Frequency Offsets

local offset plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Time Offset -2,678.941 -72.548 -40.666 -0.785 53.904 200.198 16,194.295 94.570 272.746 579.812 24.377 µs 20.56 544.8
Local Clock Frequency Offset 7.427 7.515 7.576 7.687 8.032 11.231 11.321 0.456 3.716 0.497 7.800 ppm 3230 4.845e+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 0.000 0.000 0.001 0.001 0.005 3.518 6.561 0.005 3.517 0.572 0.084 ms 5.012 51.85

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 0.000 0.060 0.109 0.762 4.223 253.624 455.894 4.114 253.564 40.361 6.783 ppb 5.006 50.15

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 -2,678.941 -72.548 -40.666 -0.785 53.904 200.198 16,194.295 94.570 272.746 579.812 24.377 µs 20.56 544.8

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 7.427 7.515 7.576 7.687 8.032 11.231 11.321 0.456 3.716 0.497 7.800 ppm 3230 4.845e+04
Temp /dev/sda 43.000 43.000 44.000 45.000 48.000 48.000 49.000 4.000 5.000 1.203 45.661 °C
Temp /dev/sdb 54.000 54.000 55.000 55.000 64.000 64.000 64.000 9.000 10.000 3.465 57.279 °C
Temp /dev/sdc 54.000 54.000 56.000 56.000 60.000 60.000 60.000 4.000 6.000 1.848 57.131 °C
Temp /dev/sdd 61.000 61.000 62.000 62.000 72.000 73.000 73.000 10.000 12.000 4.134 64.717 °C
Temp /dev/sde 43.000 43.000 44.000 45.000 50.000 50.000 50.000 6.000 7.000 2.118 46.438 °C
Temp /dev/sdf 55.000 55.000 56.000 56.000 65.000 66.000 66.000 9.000 11.000 3.717 58.516 °C
Temp LM0 37.750 38.000 38.000 38.500 40.250 41.250 41.750 2.250 3.250 0.697 38.831 °C
Temp LM1 42.000 42.000 43.500 45.000 46.000 47.000 47.000 2.500 5.000 0.738 44.869 °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 43.000 43.000 44.000 45.000 48.000 48.000 49.000 4.000 5.000 1.208 45.664 °C
Temp LM12 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp LM13 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C
Temp LM14 36.750 36.750 37.000 37.750 39.500 39.750 40.000 2.500 3.000 0.663 37.855 °C
Temp LM15 55.000 55.000 56.000 57.000 65.000 66.000 66.000 9.000 11.000 3.627 58.714 °C
Temp LM16 61.000 61.500 62.500 65.000 69.000 69.000 69.500 6.500 7.500 1.954 65.473 °C
Temp LM17 61.000 61.000 62.000 62.000 72.000 73.000 73.000 10.000 12.000 4.149 64.777 °C
Temp LM18 54.000 54.000 55.000 55.000 64.000 64.000 64.000 9.000 10.000 3.502 57.353 °C
Temp LM19 55.000 55.000 56.000 58.000 61.000 66.000 68.000 5.000 11.000 1.850 58.039 °C
Temp LM2 43.000 43.000 45.000 45.000 50.000 50.000 50.000 5.000 7.000 2.103 46.438 °C
Temp LM20 55.000 55.000 56.000 58.000 61.000 66.000 68.000 5.000 11.000 1.860 58.032 °C
Temp LM21 45.000 45.000 46.000 47.000 51.000 59.000 59.000 5.000 14.000 1.997 47.770 °C
Temp LM22 41.000 42.000 42.000 44.000 47.000 56.000 57.000 5.000 14.000 2.130 44.350 °C
Temp LM23 39.000 39.000 40.000 41.000 45.000 54.000 55.000 5.000 15.000 2.248 42.000 °C
Temp LM3 35.000 35.000 36.000 37.000 38.000 39.000 39.000 2.000 4.000 0.656 36.965 °C
Temp LM4 33.500 33.500 34.000 34.500 36.000 36.500 36.500 2.000 3.000 0.628 34.691 °C
Temp LM5 24.000 24.000 24.000 24.000 24.000 24.000 24.000 0.000 0.000 0.000 24.000 °C
Temp LM6 55.500 56.000 56.500 57.000 60.000 66.000 67.000 3.500 10.000 1.644 57.754 °C
Temp LM7 61.000 61.000 62.000 65.000 69.000 69.000 69.000 7.000 8.000 2.008 65.187 °C
Temp LM8 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM9 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp ZONE0 55.000 56.000 56.000 58.000 61.000 66.000 67.000 5.000 10.000 1.795 58.053 °C
Temp ZONE1 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp ZONE2 61.000 61.500 62.500 65.000 69.000 69.000 69.500 6.500 7.500 1.971 65.475 °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) -543.154 -228.056 -70.181 9.830 110.293 153.722 1,755.994 180.474 381.778 118.551 22.245 µs 5.556 102.9

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 -1.454 -0.778 -0.464 -0.001 1.579 3.810 17.713 2.043 4.587 1.569 0.222 ms 5.9 70.62

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 -3,343.643 -103.250 -20.616 58.930 118.576 747.320 16,127.797 139.192 850.570 1,159.241 136.081 µs 9.474 134.8

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 -3,277.968 -188.791 -48.469 37.379 112.662 991.440 16,125.276 161.131 1,180.231 1,314.298 140.520 µs 8.079 102.8

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) -74.616 -71.029 -38.914 -1.083 48.158 96.708 114.175 87.072 167.737 26.356 0.356 µs -3.232 10.71

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) 0.949 1.327 2.032 5.200 15.965 151.281 1,786.014 13.933 149.954 91.583 14.209 µs 12.73 230

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 0.000 0.002 0.005 0.014 0.100 1.130 16.232 0.096 1.128 1.224 0.138 ms 7.934 98.07

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 0.008 0.067 2.926 16.689 0.064 2.924 1.260 0.143 ms 7.734 95.57

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 1.717 2.531 8.293 53.280 299.091 16,812.945 50.749 297.374 1,239.172 126.979 µs 8.096 101.9

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) 0.191 0.307 0.636 2.614 13.563 28.250 60.202 12.927 27.943 5.866 4.305 µs 4.026 31.33

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 7.427 7.515 7.576 7.687 8.032 11.231 11.321 0.456 3.716 0.497 7.800 ppm 3230 4.845e+04
Local Clock Time Offset -2,678.941 -72.548 -40.666 -0.785 53.904 200.198 16,194.295 94.570 272.746 579.812 24.377 µs 20.56 544.8
Local RMS Frequency Jitter 0.000 0.060 0.109 0.762 4.223 253.624 455.894 4.114 253.564 40.361 6.783 ppb 5.006 50.15
Local RMS Time Jitter 0.000 0.000 0.001 0.001 0.005 3.518 6.561 0.005 3.517 0.572 0.084 ms 5.012 51.85
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.949 1.327 2.032 5.200 15.965 151.281 1,786.014 13.933 149.954 91.583 14.209 µs 12.73 230
Server Jitter 204.17.205.1 0.000 0.002 0.005 0.014 0.100 1.130 16.232 0.096 1.128 1.224 0.138 ms 7.934 98.07
Server Jitter 204.17.205.24 0.001 0.002 0.003 0.008 0.067 2.926 16.689 0.064 2.924 1.260 0.143 ms 7.734 95.57
Server Jitter 204.17.205.27 0.000 1.717 2.531 8.293 53.280 299.091 16,812.945 50.749 297.374 1,239.172 126.979 µs 8.096 101.9
Server Jitter SHM(0) 0.191 0.307 0.636 2.614 13.563 28.250 60.202 12.927 27.943 5.866 4.305 µs 4.026 31.33
Server Offset 2001:470:e815::8 (spidey.rellim.com) -543.154 -228.056 -70.181 9.830 110.293 153.722 1,755.994 180.474 381.778 118.551 22.245 µs 5.556 102.9
Server Offset 204.17.205.1 -1.454 -0.778 -0.464 -0.001 1.579 3.810 17.713 2.043 4.587 1.569 0.222 ms 5.9 70.62
Server Offset 204.17.205.24 -3,343.643 -103.250 -20.616 58.930 118.576 747.320 16,127.797 139.192 850.570 1,159.241 136.081 µs 9.474 134.8
Server Offset 204.17.205.27 -3,277.968 -188.791 -48.469 37.379 112.662 991.440 16,125.276 161.131 1,180.231 1,314.298 140.520 µs 8.079 102.8
Server Offset SHM(0) -74.616 -71.029 -38.914 -1.083 48.158 96.708 114.175 87.072 167.737 26.356 0.356 µs -3.232 10.71
Temp /dev/sda 43.000 43.000 44.000 45.000 48.000 48.000 49.000 4.000 5.000 1.203 45.661 °C
Temp /dev/sdb 54.000 54.000 55.000 55.000 64.000 64.000 64.000 9.000 10.000 3.465 57.279 °C
Temp /dev/sdc 54.000 54.000 56.000 56.000 60.000 60.000 60.000 4.000 6.000 1.848 57.131 °C
Temp /dev/sdd 61.000 61.000 62.000 62.000 72.000 73.000 73.000 10.000 12.000 4.134 64.717 °C
Temp /dev/sde 43.000 43.000 44.000 45.000 50.000 50.000 50.000 6.000 7.000 2.118 46.438 °C
Temp /dev/sdf 55.000 55.000 56.000 56.000 65.000 66.000 66.000 9.000 11.000 3.717 58.516 °C
Temp LM0 37.750 38.000 38.000 38.500 40.250 41.250 41.750 2.250 3.250 0.697 38.831 °C
Temp LM1 42.000 42.000 43.500 45.000 46.000 47.000 47.000 2.500 5.000 0.738 44.869 °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 43.000 43.000 44.000 45.000 48.000 48.000 49.000 4.000 5.000 1.208 45.664 °C
Temp LM12 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp LM13 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C
Temp LM14 36.750 36.750 37.000 37.750 39.500 39.750 40.000 2.500 3.000 0.663 37.855 °C
Temp LM15 55.000 55.000 56.000 57.000 65.000 66.000 66.000 9.000 11.000 3.627 58.714 °C
Temp LM16 61.000 61.500 62.500 65.000 69.000 69.000 69.500 6.500 7.500 1.954 65.473 °C
Temp LM17 61.000 61.000 62.000 62.000 72.000 73.000 73.000 10.000 12.000 4.149 64.777 °C
Temp LM18 54.000 54.000 55.000 55.000 64.000 64.000 64.000 9.000 10.000 3.502 57.353 °C
Temp LM19 55.000 55.000 56.000 58.000 61.000 66.000 68.000 5.000 11.000 1.850 58.039 °C
Temp LM2 43.000 43.000 45.000 45.000 50.000 50.000 50.000 5.000 7.000 2.103 46.438 °C
Temp LM20 55.000 55.000 56.000 58.000 61.000 66.000 68.000 5.000 11.000 1.860 58.032 °C
Temp LM21 45.000 45.000 46.000 47.000 51.000 59.000 59.000 5.000 14.000 1.997 47.770 °C
Temp LM22 41.000 42.000 42.000 44.000 47.000 56.000 57.000 5.000 14.000 2.130 44.350 °C
Temp LM23 39.000 39.000 40.000 41.000 45.000 54.000 55.000 5.000 15.000 2.248 42.000 °C
Temp LM3 35.000 35.000 36.000 37.000 38.000 39.000 39.000 2.000 4.000 0.656 36.965 °C
Temp LM4 33.500 33.500 34.000 34.500 36.000 36.500 36.500 2.000 3.000 0.628 34.691 °C
Temp LM5 24.000 24.000 24.000 24.000 24.000 24.000 24.000 0.000 0.000 0.000 24.000 °C
Temp LM6 55.500 56.000 56.500 57.000 60.000 66.000 67.000 3.500 10.000 1.644 57.754 °C
Temp LM7 61.000 61.000 62.000 65.000 69.000 69.000 69.000 7.000 8.000 2.008 65.187 °C
Temp LM8 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM9 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp ZONE0 55.000 56.000 56.000 58.000 61.000 66.000 67.000 5.000 10.000 1.795 58.053 °C
Temp ZONE1 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp ZONE2 61.000 61.500 62.500 65.000 69.000 69.000 69.500 6.500 7.500 1.971 65.475 °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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