NTPsec

Backup/Meinberg

Report generated: Wed Dec 6 16:43:02 2023 UTC
Start Time: Wed Nov 29 16:43:01 2023 UTC
End Time: Wed Dec 6 16:43:01 2023 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 -54.813 -40.950 -31.930 -6.596 51.306 68.658 114.638 83.236 109.608 25.174 0.130 µs -3.009 6.804
Local Clock Frequency Offset -0.0196 0.0148 0.123 0.560 0.898 1.001 1.084 0.775 0.986 0.249 0.530 ppm 4.721 10.81

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 0.289 0.443 0.534 1.077 2.807 5.159 10.585 2.273 4.716 0.925 1.351 µs 4.557 26.78

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 0.129 0.225 0.339 1.010 3.179 3.974 5.790 2.840 3.749 0.884 1.255 ppb 2.78 8.758

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 -54.813 -40.950 -31.930 -6.596 51.306 68.658 114.638 83.236 109.608 25.174 0.130 µs -3.009 6.804

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 -0.0196 0.0148 0.123 0.560 0.898 1.001 1.084 0.775 0.986 0.249 0.530 ppm 4.721 10.81
Temp /dev/sda 41.000 41.000 42.000 43.000 46.000 46.000 50.000 4.000 5.000 1.217 43.141 °C
Temp /dev/sdb 50.000 51.000 52.000 54.000 61.000 62.000 63.000 9.000 11.000 2.442 54.076 °C
Temp /dev/sdc 51.000 53.000 53.000 54.000 56.000 58.000 60.000 3.000 5.000 1.401 54.272 °C
Temp /dev/sdd 57.000 58.000 58.000 61.000 70.000 71.000 71.000 12.000 13.000 2.972 61.325 °C
Temp /dev/sde 41.000 41.000 42.000 43.000 47.000 48.000 48.000 5.000 7.000 1.504 43.489 °C
Temp /dev/sdf 52.000 52.000 53.000 55.000 62.000 64.000 64.000 9.000 12.000 2.672 55.396 °C
Temp LM0 34.500 34.750 35.250 36.750 38.250 39.000 40.750 3.000 4.250 0.937 36.695 °C
Temp LM1 39.500 40.500 41.500 43.000 44.500 45.000 46.000 3.000 4.500 1.039 42.948 °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 42.000 43.000 46.000 46.000 50.000 4.000 5.000 1.216 43.140 °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 33.000 33.250 33.750 35.500 37.250 38.250 39.000 3.500 5.000 1.099 35.385 °C
Temp LM16 52.000 52.000 53.000 55.000 63.000 64.000 65.000 10.000 12.000 2.705 55.508 °C
Temp LM17 59.500 59.500 60.000 62.500 64.500 67.000 67.500 4.500 7.500 1.456 62.367 °C
Temp LM18 57.000 58.000 59.000 61.000 70.000 71.000 71.000 11.000 13.000 2.982 61.474 °C
Temp LM19 51.000 51.000 52.000 54.000 61.000 62.000 63.000 9.000 11.000 2.487 54.164 °C
Temp LM2 41.000 41.000 42.000 43.000 47.000 48.000 49.000 5.000 7.000 1.511 43.494 °C
Temp LM20 53.000 54.000 54.000 56.000 58.000 61.000 72.000 4.000 7.000 1.534 56.240 °C
Temp LM21 53.000 54.000 54.000 56.000 58.000 61.000 72.000 4.000 7.000 1.539 56.244 °C
Temp LM22 42.000 43.000 43.000 45.000 48.000 51.000 65.000 5.000 8.000 1.841 45.378 °C
Temp LM23 39.000 40.000 41.000 42.000 44.000 48.000 65.000 3.000 8.000 1.828 42.597 °C
Temp LM24 36.000 37.000 38.000 39.000 42.000 47.000 60.000 4.000 10.000 1.827 39.556 °C
Temp LM3 32.000 32.000 33.000 35.000 36.000 37.000 38.000 3.000 5.000 1.128 34.557 °C
Temp LM4 29.500 29.500 30.500 32.500 34.500 35.000 35.500 4.000 5.500 1.309 32.280 °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 53.000 54.000 54.500 56.000 57.500 60.500 70.500 3.000 6.500 1.398 56.004 °C
Temp LM7 59.000 59.000 60.000 62.000 64.000 67.000 67.000 4.000 8.000 1.450 62.111 °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 54.000 54.000 56.000 58.000 61.000 71.000 4.000 7.000 1.538 56.243 °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 59.500 60.000 62.500 65.000 67.000 67.500 5.000 7.500 1.458 62.371 °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) -0.432 -0.297 -0.220 0.027 0.133 0.195 19.750 0.353 0.492 0.315 0.012 ms 52.29 3302

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 -1,178.628 -833.612 -621.152 38.105 326.363 442.700 508.291 947.515 1,276.312 273.017 -27.511 µs -5.74 17.83

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 204.17.205.24

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 -176.814 -32.063 -6.478 53.918 110.362 133.402 198.880 116.840 165.465 34.244 53.566 µs 1.666 6.301

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 -339.488 -85.838 -13.002 31.925 78.870 137.419 350.154 91.872 223.257 37.961 31.949 µs -0.6932 21.71

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 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) -54.814 -40.951 -31.931 -6.597 51.307 68.659 114.639 83.238 109.610 25.175 0.129 µs -3.009 6.804

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) 0.000 0.001 0.002 0.005 0.013 0.022 27.577 0.011 0.020 0.419 0.013 ms 61.3 4031

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 1.087 2.735 4.100 12.005 29.377 39.395 400.412 25.277 36.660 14.387 14.012 µs 18.46 485.3

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 0.730 1.934 3.024 8.674 58.335 73.449 3,256.392 55.311 71.515 88.981 18.967 µs 31.99 1159

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 0.483 1.535 2.520 8.563 28.676 63.665 154.818 26.156 62.130 11.864 11.768 µs 4.524 36.43

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter SHM(0)

peer jitter SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(0) 0.167 0.372 0.636 3.016 12.203 22.149 59.670 11.567 21.777 4.500 4.426 µs 3.406 25.43

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -0.0196 0.0148 0.123 0.560 0.898 1.001 1.084 0.775 0.986 0.249 0.530 ppm 4.721 10.81
Local Clock Time Offset -54.813 -40.950 -31.930 -6.596 51.306 68.658 114.638 83.236 109.608 25.174 0.130 µs -3.009 6.804
Local RMS Frequency Jitter 0.129 0.225 0.339 1.010 3.179 3.974 5.790 2.840 3.749 0.884 1.255 ppb 2.78 8.758
Local RMS Time Jitter 0.289 0.443 0.534 1.077 2.807 5.159 10.585 2.273 4.716 0.925 1.351 µs 4.557 26.78
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.000 0.001 0.002 0.005 0.013 0.022 27.577 0.011 0.020 0.419 0.013 ms 61.3 4031
Server Jitter 204.17.205.1 1.087 2.735 4.100 12.005 29.377 39.395 400.412 25.277 36.660 14.387 14.012 µs 18.46 485.3
Server Jitter 204.17.205.24 0.730 1.934 3.024 8.674 58.335 73.449 3,256.392 55.311 71.515 88.981 18.967 µs 31.99 1159
Server Jitter 204.17.205.27 0.483 1.535 2.520 8.563 28.676 63.665 154.818 26.156 62.130 11.864 11.768 µs 4.524 36.43
Server Jitter SHM(0) 0.167 0.372 0.636 3.016 12.203 22.149 59.670 11.567 21.777 4.500 4.426 µs 3.406 25.43
Server Offset 2001:470:e815::8 (spidey.rellim.com) -0.432 -0.297 -0.220 0.027 0.133 0.195 19.750 0.353 0.492 0.315 0.012 ms 52.29 3302
Server Offset 204.17.205.1 -1,178.628 -833.612 -621.152 38.105 326.363 442.700 508.291 947.515 1,276.312 273.017 -27.511 µs -5.74 17.83
Server Offset 204.17.205.24 -176.814 -32.063 -6.478 53.918 110.362 133.402 198.880 116.840 165.465 34.244 53.566 µs 1.666 6.301
Server Offset 204.17.205.27 -339.488 -85.838 -13.002 31.925 78.870 137.419 350.154 91.872 223.257 37.961 31.949 µs -0.6932 21.71
Server Offset SHM(0) -54.814 -40.951 -31.931 -6.597 51.307 68.659 114.639 83.238 109.610 25.175 0.129 µs -3.009 6.804
Temp /dev/sda 41.000 41.000 42.000 43.000 46.000 46.000 50.000 4.000 5.000 1.217 43.141 °C
Temp /dev/sdb 50.000 51.000 52.000 54.000 61.000 62.000 63.000 9.000 11.000 2.442 54.076 °C
Temp /dev/sdc 51.000 53.000 53.000 54.000 56.000 58.000 60.000 3.000 5.000 1.401 54.272 °C
Temp /dev/sdd 57.000 58.000 58.000 61.000 70.000 71.000 71.000 12.000 13.000 2.972 61.325 °C
Temp /dev/sde 41.000 41.000 42.000 43.000 47.000 48.000 48.000 5.000 7.000 1.504 43.489 °C
Temp /dev/sdf 52.000 52.000 53.000 55.000 62.000 64.000 64.000 9.000 12.000 2.672 55.396 °C
Temp LM0 34.500 34.750 35.250 36.750 38.250 39.000 40.750 3.000 4.250 0.937 36.695 °C
Temp LM1 39.500 40.500 41.500 43.000 44.500 45.000 46.000 3.000 4.500 1.039 42.948 °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 42.000 43.000 46.000 46.000 50.000 4.000 5.000 1.216 43.140 °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 33.000 33.250 33.750 35.500 37.250 38.250 39.000 3.500 5.000 1.099 35.385 °C
Temp LM16 52.000 52.000 53.000 55.000 63.000 64.000 65.000 10.000 12.000 2.705 55.508 °C
Temp LM17 59.500 59.500 60.000 62.500 64.500 67.000 67.500 4.500 7.500 1.456 62.367 °C
Temp LM18 57.000 58.000 59.000 61.000 70.000 71.000 71.000 11.000 13.000 2.982 61.474 °C
Temp LM19 51.000 51.000 52.000 54.000 61.000 62.000 63.000 9.000 11.000 2.487 54.164 °C
Temp LM2 41.000 41.000 42.000 43.000 47.000 48.000 49.000 5.000 7.000 1.511 43.494 °C
Temp LM20 53.000 54.000 54.000 56.000 58.000 61.000 72.000 4.000 7.000 1.534 56.240 °C
Temp LM21 53.000 54.000 54.000 56.000 58.000 61.000 72.000 4.000 7.000 1.539 56.244 °C
Temp LM22 42.000 43.000 43.000 45.000 48.000 51.000 65.000 5.000 8.000 1.841 45.378 °C
Temp LM23 39.000 40.000 41.000 42.000 44.000 48.000 65.000 3.000 8.000 1.828 42.597 °C
Temp LM24 36.000 37.000 38.000 39.000 42.000 47.000 60.000 4.000 10.000 1.827 39.556 °C
Temp LM3 32.000 32.000 33.000 35.000 36.000 37.000 38.000 3.000 5.000 1.128 34.557 °C
Temp LM4 29.500 29.500 30.500 32.500 34.500 35.000 35.500 4.000 5.500 1.309 32.280 °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 53.000 54.000 54.500 56.000 57.500 60.500 70.500 3.000 6.500 1.398 56.004 °C
Temp LM7 59.000 59.000 60.000 62.000 64.000 67.000 67.000 4.000 8.000 1.450 62.111 °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 54.000 54.000 56.000 58.000 61.000 71.000 4.000 7.000 1.538 56.243 °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 59.500 60.000 62.500 65.000 67.000 67.500 5.000 7.500 1.458 62.371 °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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