NTPsec

Backup/Meinberg

Report generated: Mon Jun 22 17:33:01 2026 UTC
Start Time: Sun Jun 21 17:33:00 2026 UTC
End Time: Mon Jun 22 17:33:00 2026 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 -20.038 -18.082 -14.366 -3.043 18.423 96.932 153.602 32.789 115.014 17.512 0.238 µs 4.959 37.13
Local Clock Frequency Offset 6.852 6.853 6.855 7.044 7.230 7.231 7.231 0.375 0.378 0.143 7.051 ppm -0.04667 1.346

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 0.400 0.440 0.495 0.783 3.028 9.325 10.296 2.533 8.885 1.383 1.102 µs 4.81 27.09

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 0.044 0.060 0.101 0.473 1.166 5.889 7.634 1.065 5.829 0.865 0.630 ppb 5.369 37.16

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 -20.038 -18.082 -14.366 -3.043 18.423 96.932 153.602 32.789 115.014 17.512 0.238 µs 4.959 37.13

The clock offsets of the local clock as a histogram.

The Local Clock Offset is field 3 from the loopstats log file.



Local Temperatures

local temps plot

Local temperatures. These will be site-specific depending upon what temperature sensors you collect data from. Temperature changes affect the local clock crystal frequency and stability. The math of how temperature changes frequency is complex, and also depends on crystal aging. So there is no easy way to correct for it in software. This is the single most important component of frequency drift.

The Local Temperatures are from field 3 from the tempstats log file.



Local Frequency/Temp

local freq temps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset 6.852 6.853 6.855 7.044 7.230 7.231 7.231 0.375 0.378 0.143 7.051 ppm -0.04667 1.346
Temp /dev/sda 45.000 45.000 45.000 46.000 56.000 56.000 56.000 11.000 11.000 4.798 49.035 °C
Temp /dev/sdb 47.000 47.000 47.000 48.000 49.000 50.000 51.000 2.000 3.000 0.886 48.161 °C
Temp /dev/sdc 58.000 58.000 58.000 60.000 63.000 63.000 63.000 5.000 5.000 1.126 60.399 °C
Temp /dev/sdd 71.000 71.000 71.000 72.000 74.000 74.000 74.000 3.000 3.000 0.851 72.290 °C
Temp /dev/sde 51.000 51.000 51.000 52.000 54.000 54.000 54.000 3.000 3.000 1.274 52.434 °C
Temp /dev/sdf 48.000 48.000 48.000 49.000 51.000 51.000 51.000 3.000 3.000 0.961 49.573 °C
Temp LM0 30.000 30.000 30.000 31.000 32.500 37.500 39.750 2.500 7.500 1.179 31.221 °C
Temp LM1 43.500 44.000 44.000 45.000 46.000 46.500 47.000 2.000 2.500 0.707 45.171 °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 45.000 45.000 45.000 46.000 56.000 56.000 56.000 11.000 11.000 4.795 49.038 °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 31.000 31.250 31.250 32.500 33.750 36.000 37.250 2.500 4.750 1.002 32.498 °C
Temp LM16 48.000 48.000 48.000 49.000 51.000 51.000 51.000 3.000 3.000 0.935 49.608 °C
Temp LM17 61.500 61.500 61.500 62.500 63.500 64.500 65.000 2.000 3.000 0.716 62.685 °C
Temp LM18 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM19 47.000 47.000 47.000 48.000 49.000 50.000 51.000 2.000 3.000 0.894 48.182 °C
Temp LM2 51.000 51.000 51.000 52.000 54.000 54.000 54.000 3.000 3.000 1.269 52.455 °C
Temp LM20 28.000 28.000 29.000 30.000 32.000 43.000 62.000 3.000 15.000 2.904 30.577 °C
Temp LM21 28.000 28.000 28.000 30.000 32.000 40.000 53.000 4.000 12.000 2.208 30.273 °C
Temp LM22 25.000 26.000 26.000 28.000 30.000 43.000 62.000 4.000 17.000 3.109 28.297 °C
Temp LM23 26.000 27.000 27.000 29.000 32.000 40.000 60.000 5.000 13.000 2.861 29.416 °C
Temp LM24 27.000 27.000 28.000 29.000 31.000 38.000 59.000 3.000 11.000 2.522 29.524 °C
Temp LM3 35.000 35.000 35.000 36.000 36.000 38.000 39.000 1.000 3.000 0.658 35.580 °C
Temp LM4 32.500 32.500 32.500 34.000 35.500 36.500 36.500 3.000 4.000 1.060 34.184 °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 28.500 28.500 28.500 30.000 31.500 40.500 60.500 3.000 12.000 2.855 30.156 °C
Temp LM7 61.000 61.000 61.000 62.000 63.000 64.000 64.000 2.000 3.000 0.661 62.374 °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 28.000 28.000 29.000 30.000 32.000 44.000 60.000 3.000 16.000 2.889 30.385 °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 61.500 61.500 61.500 62.500 63.500 64.500 65.000 2.000 3.000 0.705 62.687 °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) -621.654 -569.357 -235.617 28.240 147.020 161.298 183.659 382.637 730.655 131.430 -3.846 µs -1.993 8.71

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 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 -686.979 -625.268 -266.311 13.270 305.998 344.678 365.059 572.309 969.946 203.514 13.483 µs -0.6167 3.454

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 -90.743 -49.003 -6.297 50.276 90.751 167.142 223.232 97.048 216.145 32.829 47.251 µs 0.3339 8.237

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 -416.110 -112.337 -24.371 46.924 136.565 209.048 425.832 160.936 321.385 63.729 50.693 µs -0.7956 18.89

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) -20.039 -18.083 -14.367 -3.044 18.424 96.933 153.603 32.791 115.016 17.512 0.238 µs 4.958 37.13

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) 2.375 3.228 5.410 15.878 66.732 90.212 111.105 61.322 86.984 20.506 24.561 µs 1.364 4.318

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 4.320 6.943 9.111 17.533 33.491 45.514 89.747 24.380 38.571 9.052 19.197 µs 2.401 15.07

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 3.683 4.466 7.770 23.642 58.325 90.988 125.175 50.555 86.522 16.555 26.499 µs 2.147 10.17

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 8.713 12.139 24.038 87.250 148.465 170.394 205.387 124.427 158.255 36.135 86.268 µs 0.04574 2.902

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) 0.178 0.329 0.498 1.595 6.327 43.103 56.783 5.829 42.774 6.211 2.943 µs 6.043 42.53

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

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

RMS Jitter is field 8 in the peerstats log file.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset 6.852 6.853 6.855 7.044 7.230 7.231 7.231 0.375 0.378 0.143 7.051 ppm -0.04667 1.346
Local Clock Time Offset -20.038 -18.082 -14.366 -3.043 18.423 96.932 153.602 32.789 115.014 17.512 0.238 µs 4.959 37.13
Local RMS Frequency Jitter 0.044 0.060 0.101 0.473 1.166 5.889 7.634 1.065 5.829 0.865 0.630 ppb 5.369 37.16
Local RMS Time Jitter 0.400 0.440 0.495 0.783 3.028 9.325 10.296 2.533 8.885 1.383 1.102 µs 4.81 27.09
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 2.375 3.228 5.410 15.878 66.732 90.212 111.105 61.322 86.984 20.506 24.561 µs 1.364 4.318
Server Jitter 204.17.205.1 4.320 6.943 9.111 17.533 33.491 45.514 89.747 24.380 38.571 9.052 19.197 µs 2.401 15.07
Server Jitter 204.17.205.24 3.683 4.466 7.770 23.642 58.325 90.988 125.175 50.555 86.522 16.555 26.499 µs 2.147 10.17
Server Jitter 204.17.205.27 8.713 12.139 24.038 87.250 148.465 170.394 205.387 124.427 158.255 36.135 86.268 µs 0.04574 2.902
Server Jitter SHM(0) 0.178 0.329 0.498 1.595 6.327 43.103 56.783 5.829 42.774 6.211 2.943 µs 6.043 42.53
Server Offset 2001:470:e815::8 (spidey.rellim.com) -621.654 -569.357 -235.617 28.240 147.020 161.298 183.659 382.637 730.655 131.430 -3.846 µs -1.993 8.71
Server Offset 204.17.205.1 -686.979 -625.268 -266.311 13.270 305.998 344.678 365.059 572.309 969.946 203.514 13.483 µs -0.6167 3.454
Server Offset 204.17.205.24 -90.743 -49.003 -6.297 50.276 90.751 167.142 223.232 97.048 216.145 32.829 47.251 µs 0.3339 8.237
Server Offset 204.17.205.27 -416.110 -112.337 -24.371 46.924 136.565 209.048 425.832 160.936 321.385 63.729 50.693 µs -0.7956 18.89
Server Offset SHM(0) -20.039 -18.083 -14.367 -3.044 18.424 96.933 153.603 32.791 115.016 17.512 0.238 µs 4.958 37.13
Temp /dev/sda 45.000 45.000 45.000 46.000 56.000 56.000 56.000 11.000 11.000 4.798 49.035 °C
Temp /dev/sdb 47.000 47.000 47.000 48.000 49.000 50.000 51.000 2.000 3.000 0.886 48.161 °C
Temp /dev/sdc 58.000 58.000 58.000 60.000 63.000 63.000 63.000 5.000 5.000 1.126 60.399 °C
Temp /dev/sdd 71.000 71.000 71.000 72.000 74.000 74.000 74.000 3.000 3.000 0.851 72.290 °C
Temp /dev/sde 51.000 51.000 51.000 52.000 54.000 54.000 54.000 3.000 3.000 1.274 52.434 °C
Temp /dev/sdf 48.000 48.000 48.000 49.000 51.000 51.000 51.000 3.000 3.000 0.961 49.573 °C
Temp LM0 30.000 30.000 30.000 31.000 32.500 37.500 39.750 2.500 7.500 1.179 31.221 °C
Temp LM1 43.500 44.000 44.000 45.000 46.000 46.500 47.000 2.000 2.500 0.707 45.171 °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 45.000 45.000 45.000 46.000 56.000 56.000 56.000 11.000 11.000 4.795 49.038 °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 31.000 31.250 31.250 32.500 33.750 36.000 37.250 2.500 4.750 1.002 32.498 °C
Temp LM16 48.000 48.000 48.000 49.000 51.000 51.000 51.000 3.000 3.000 0.935 49.608 °C
Temp LM17 61.500 61.500 61.500 62.500 63.500 64.500 65.000 2.000 3.000 0.716 62.685 °C
Temp LM18 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM19 47.000 47.000 47.000 48.000 49.000 50.000 51.000 2.000 3.000 0.894 48.182 °C
Temp LM2 51.000 51.000 51.000 52.000 54.000 54.000 54.000 3.000 3.000 1.269 52.455 °C
Temp LM20 28.000 28.000 29.000 30.000 32.000 43.000 62.000 3.000 15.000 2.904 30.577 °C
Temp LM21 28.000 28.000 28.000 30.000 32.000 40.000 53.000 4.000 12.000 2.208 30.273 °C
Temp LM22 25.000 26.000 26.000 28.000 30.000 43.000 62.000 4.000 17.000 3.109 28.297 °C
Temp LM23 26.000 27.000 27.000 29.000 32.000 40.000 60.000 5.000 13.000 2.861 29.416 °C
Temp LM24 27.000 27.000 28.000 29.000 31.000 38.000 59.000 3.000 11.000 2.522 29.524 °C
Temp LM3 35.000 35.000 35.000 36.000 36.000 38.000 39.000 1.000 3.000 0.658 35.580 °C
Temp LM4 32.500 32.500 32.500 34.000 35.500 36.500 36.500 3.000 4.000 1.060 34.184 °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 28.500 28.500 28.500 30.000 31.500 40.500 60.500 3.000 12.000 2.855 30.156 °C
Temp LM7 61.000 61.000 61.000 62.000 63.000 64.000 64.000 2.000 3.000 0.661 62.374 °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 28.000 28.000 29.000 30.000 32.000 44.000 60.000 3.000 16.000 2.889 30.385 °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 61.500 61.500 61.500 62.500 63.500 64.500 65.000 2.000 3.000 0.705 62.687 °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.
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 FIsher-Pearson moment of skewness. There are other different ways to calculate Skewness Wikipedia describes Skewness best: "The qualitative interpretation of the skew is complicated and unintuitive."
A normal distribution has a skewness of zero.
Kurtosis, Kurt:
The kurtosis of a random variable X is the fourth standardized moment and is a dimension-less ratio. ntpviz uses standard Kurtosis. There are other different ways to calculate 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".
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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