NTPsec

Backup/Meinberg

Report generated: Tue May 5 15:43:01 2026 UTC
Start Time: Tue Apr 28 15:43:00 2026 UTC
End Time: Tue May 5 15:43:00 2026 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 -86.375 -45.293 -20.346 -1.484 25.461 101.228 205.276 45.807 146.521 21.824 1.210 µs 3.437 25.78
Local Clock Frequency Offset 10.980 11.052 11.229 11.687 12.145 12.312 12.334 0.915 1.260 0.281 11.664 ppm 0.03073 2.471

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 0.345 0.447 0.520 0.837 3.138 8.717 15.006 2.618 8.270 1.390 1.205 µs 4.972 32.2

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 0.052 0.083 0.130 0.544 2.602 6.150 10.396 2.472 6.067 1.066 0.804 ppb 4.662 31.05

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 -86.375 -45.293 -20.346 -1.484 25.461 101.228 205.276 45.807 146.521 21.824 1.210 µs 3.437 25.78

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 10.980 11.052 11.229 11.687 12.145 12.312 12.334 0.915 1.260 0.281 11.664 ppm 0.03073 2.471
Temp /dev/sda 41.000 42.000 42.000 44.000 46.000 47.000 50.000 4.000 5.000 1.351 44.082 °C
Temp /dev/sdb 52.000 52.000 53.000 55.000 62.000 64.000 65.000 9.000 12.000 2.582 55.537 °C
Temp /dev/sdc 53.000 53.000 53.000 56.000 56.000 58.000 61.000 3.000 5.000 1.379 54.967 °C
Temp /dev/sdd 59.000 59.000 60.000 62.000 71.000 72.000 73.000 11.000 13.000 2.996 62.631 °C
Temp /dev/sde 41.000 41.000 42.000 44.000 46.000 46.000 47.000 4.000 5.000 1.267 43.963 °C
Temp /dev/sdf 52.000 53.000 53.000 55.000 63.000 65.000 65.000 10.000 12.000 2.671 56.071 °C
Temp LM0 25.500 25.750 26.500 28.500 30.750 34.500 49.250 4.250 8.750 1.925 28.611 °C
Temp LM1 36.500 37.000 38.000 40.000 42.000 42.000 42.500 4.000 5.000 1.229 39.846 °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 42.000 42.000 44.000 46.000 47.000 50.000 4.000 5.000 1.350 44.083 °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 26.750 27.000 27.750 29.750 32.000 34.000 39.500 4.250 7.000 1.453 29.755 °C
Temp LM16 52.000 53.000 53.000 56.000 63.000 65.000 65.000 10.000 12.000 2.692 56.178 °C
Temp LM17 56.500 57.000 57.500 60.000 62.000 65.500 67.000 4.500 8.500 1.554 59.818 °C
Temp LM18 59.000 59.000 60.000 62.000 71.000 73.000 73.000 11.000 14.000 3.021 62.774 °C
Temp LM19 52.000 52.000 53.000 55.000 62.000 64.000 65.000 9.000 12.000 2.615 55.640 °C
Temp LM2 41.000 41.000 42.000 44.000 46.000 46.000 47.000 4.000 5.000 1.269 43.956 °C
Temp LM20 23.000 24.000 25.000 28.000 31.000 56.000 99.000 6.000 32.000 5.120 28.361 °C
Temp LM21 23.000 24.000 25.000 28.000 31.000 49.000 99.000 6.000 25.000 4.945 28.046 °C
Temp LM22 21.000 22.000 23.000 25.000 29.000 49.000 97.000 6.000 27.000 4.869 25.842 °C
Temp LM23 22.000 23.000 24.000 27.000 30.000 50.000 93.000 6.000 27.000 4.707 27.403 °C
Temp LM24 23.000 24.000 25.000 27.000 30.000 48.000 88.000 5.000 24.000 4.292 27.302 °C
Temp LM3 30.000 30.000 31.000 33.000 35.000 35.000 39.000 4.000 5.000 1.255 32.594 °C
Temp LM4 27.500 28.000 29.000 31.000 33.500 33.500 34.500 4.500 5.500 1.321 31.107 °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 29.000 29.000 29.000 29.000 29.000 29.000 29.000 0.000 0.000 0.000 29.000 °C
Temp LM7 56.000 57.000 57.000 60.000 62.000 66.000 67.000 5.000 9.000 1.586 59.635 °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 24.000 24.000 25.000 28.000 31.000 54.000 100.000 6.000 30.000 5.120 28.113 °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 56.500 57.000 57.500 60.000 62.000 65.500 67.000 4.500 8.500 1.558 59.814 °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) -746.197 -517.769 -276.127 22.468 177.478 271.875 361.991 453.605 789.644 139.121 2.222 µs -1.426 7.149

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 -1.707 -1.075 -0.475 0.005 0.464 0.569 0.705 0.939 1.644 0.296 -0.010 ms -1.09 7.207

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 -87.154 -36.495 -7.328 48.592 85.540 156.645 265.643 92.868 193.140 31.983 46.984 µs 0.8111 9.28

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 -616.866 -114.211 -10.356 45.402 108.392 216.224 613.598 118.748 330.435 57.861 45.561 µs -0.2813 34.36

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) -86.375 -45.294 -20.347 -1.485 25.462 101.229 205.277 45.809 146.523 21.825 1.209 µs 3.437 25.78

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) 1.092 3.014 5.159 25.807 87.325 106.525 147.031 82.166 103.511 27.555 34.572 µs 0.848 2.842

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 2.638 5.539 8.413 17.054 38.027 76.159 374.084 29.614 70.620 15.119 20.136 µs 7.806 117.9

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 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 0.924 2.900 4.297 21.876 46.590 70.279 98.887 42.293 67.379 14.018 22.710 µs 1.148 5.352

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 2.080 5.676 10.223 93.709 161.811 189.383 308.684 151.588 183.707 48.322 87.570 µs -0.07207 2.254

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) 0.155 0.387 0.571 1.934 9.745 36.754 83.812 9.174 36.367 6.242 3.396 µs 6.439 54.28

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 10.980 11.052 11.229 11.687 12.145 12.312 12.334 0.915 1.260 0.281 11.664 ppm 0.03073 2.471
Local Clock Time Offset -86.375 -45.293 -20.346 -1.484 25.461 101.228 205.276 45.807 146.521 21.824 1.210 µs 3.437 25.78
Local RMS Frequency Jitter 0.052 0.083 0.130 0.544 2.602 6.150 10.396 2.472 6.067 1.066 0.804 ppb 4.662 31.05
Local RMS Time Jitter 0.345 0.447 0.520 0.837 3.138 8.717 15.006 2.618 8.270 1.390 1.205 µs 4.972 32.2
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 1.092 3.014 5.159 25.807 87.325 106.525 147.031 82.166 103.511 27.555 34.572 µs 0.848 2.842
Server Jitter 204.17.205.1 2.638 5.539 8.413 17.054 38.027 76.159 374.084 29.614 70.620 15.119 20.136 µs 7.806 117.9
Server Jitter 204.17.205.24 0.924 2.900 4.297 21.876 46.590 70.279 98.887 42.293 67.379 14.018 22.710 µs 1.148 5.352
Server Jitter 204.17.205.27 2.080 5.676 10.223 93.709 161.811 189.383 308.684 151.588 183.707 48.322 87.570 µs -0.07207 2.254
Server Jitter SHM(0) 0.155 0.387 0.571 1.934 9.745 36.754 83.812 9.174 36.367 6.242 3.396 µs 6.439 54.28
Server Offset 2001:470:e815::8 (spidey.rellim.com) -746.197 -517.769 -276.127 22.468 177.478 271.875 361.991 453.605 789.644 139.121 2.222 µs -1.426 7.149
Server Offset 204.17.205.1 -1.707 -1.075 -0.475 0.005 0.464 0.569 0.705 0.939 1.644 0.296 -0.010 ms -1.09 7.207
Server Offset 204.17.205.24 -87.154 -36.495 -7.328 48.592 85.540 156.645 265.643 92.868 193.140 31.983 46.984 µs 0.8111 9.28
Server Offset 204.17.205.27 -616.866 -114.211 -10.356 45.402 108.392 216.224 613.598 118.748 330.435 57.861 45.561 µs -0.2813 34.36
Server Offset SHM(0) -86.375 -45.294 -20.347 -1.485 25.462 101.229 205.277 45.809 146.523 21.825 1.209 µs 3.437 25.78
Temp /dev/sda 41.000 42.000 42.000 44.000 46.000 47.000 50.000 4.000 5.000 1.351 44.082 °C
Temp /dev/sdb 52.000 52.000 53.000 55.000 62.000 64.000 65.000 9.000 12.000 2.582 55.537 °C
Temp /dev/sdc 53.000 53.000 53.000 56.000 56.000 58.000 61.000 3.000 5.000 1.379 54.967 °C
Temp /dev/sdd 59.000 59.000 60.000 62.000 71.000 72.000 73.000 11.000 13.000 2.996 62.631 °C
Temp /dev/sde 41.000 41.000 42.000 44.000 46.000 46.000 47.000 4.000 5.000 1.267 43.963 °C
Temp /dev/sdf 52.000 53.000 53.000 55.000 63.000 65.000 65.000 10.000 12.000 2.671 56.071 °C
Temp LM0 25.500 25.750 26.500 28.500 30.750 34.500 49.250 4.250 8.750 1.925 28.611 °C
Temp LM1 36.500 37.000 38.000 40.000 42.000 42.000 42.500 4.000 5.000 1.229 39.846 °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 42.000 42.000 44.000 46.000 47.000 50.000 4.000 5.000 1.350 44.083 °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 26.750 27.000 27.750 29.750 32.000 34.000 39.500 4.250 7.000 1.453 29.755 °C
Temp LM16 52.000 53.000 53.000 56.000 63.000 65.000 65.000 10.000 12.000 2.692 56.178 °C
Temp LM17 56.500 57.000 57.500 60.000 62.000 65.500 67.000 4.500 8.500 1.554 59.818 °C
Temp LM18 59.000 59.000 60.000 62.000 71.000 73.000 73.000 11.000 14.000 3.021 62.774 °C
Temp LM19 52.000 52.000 53.000 55.000 62.000 64.000 65.000 9.000 12.000 2.615 55.640 °C
Temp LM2 41.000 41.000 42.000 44.000 46.000 46.000 47.000 4.000 5.000 1.269 43.956 °C
Temp LM20 23.000 24.000 25.000 28.000 31.000 56.000 99.000 6.000 32.000 5.120 28.361 °C
Temp LM21 23.000 24.000 25.000 28.000 31.000 49.000 99.000 6.000 25.000 4.945 28.046 °C
Temp LM22 21.000 22.000 23.000 25.000 29.000 49.000 97.000 6.000 27.000 4.869 25.842 °C
Temp LM23 22.000 23.000 24.000 27.000 30.000 50.000 93.000 6.000 27.000 4.707 27.403 °C
Temp LM24 23.000 24.000 25.000 27.000 30.000 48.000 88.000 5.000 24.000 4.292 27.302 °C
Temp LM3 30.000 30.000 31.000 33.000 35.000 35.000 39.000 4.000 5.000 1.255 32.594 °C
Temp LM4 27.500 28.000 29.000 31.000 33.500 33.500 34.500 4.500 5.500 1.321 31.107 °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 29.000 29.000 29.000 29.000 29.000 29.000 29.000 0.000 0.000 0.000 29.000 °C
Temp LM7 56.000 57.000 57.000 60.000 62.000 66.000 67.000 5.000 9.000 1.586 59.635 °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 24.000 24.000 25.000 28.000 31.000 54.000 100.000 6.000 30.000 5.120 28.113 °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 56.500 57.000 57.500 60.000 62.000 65.500 67.000 4.500 8.500 1.558 59.814 °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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