NTPsec

Backup/Meinberg

Report generated: Sat Mar 21 15:43:01 2026 UTC
Start Time: Sat Mar 14 15:43:00 2026 UTC
End Time: Sat Mar 21 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 -0.746 -0.048 -0.027 -0.002 0.045 0.138 7.967 0.072 0.185 0.126 0.005 ms 53.87 3184
Local Clock Frequency Offset 4.735 4.782 4.866 5.325 6.458 6.618 6.639 1.591 1.836 0.387 5.400 ppm 1.648 5.969

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 0.547 0.660 0.797 1.375 3.973 13.668 2,904.067 3.176 13.008 98.180 7.347 µs 22.18 541.6

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 0.150 0.208 0.681 3.161 8.074 155.780 2.953 7.924 4.921 1.306 ppb 20.22 490.3

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 -0.746 -0.048 -0.027 -0.002 0.045 0.138 7.967 0.072 0.185 0.126 0.005 ms 53.87 3184

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 4.735 4.782 4.866 5.325 6.458 6.618 6.639 1.591 1.836 0.387 5.400 ppm 1.648 5.969
Temp /dev/sda 40.000 41.000 41.000 43.000 44.000 45.000 49.000 3.000 4.000 1.043 42.725 °C
Temp /dev/sdb 52.000 52.000 52.000 54.000 61.000 63.000 63.000 9.000 11.000 2.230 54.591 °C
Temp /dev/sdc 53.000 53.000 53.000 54.000 56.000 56.000 60.000 3.000 3.000 0.996 54.044 °C
Temp /dev/sdd 58.000 59.000 59.000 61.000 70.000 71.000 71.000 11.000 12.000 2.712 61.809 °C
Temp /dev/sde 41.000 41.000 42.000 43.000 45.000 45.000 46.000 3.000 4.000 0.953 43.153 °C
Temp /dev/sdf 52.000 52.000 53.000 55.000 62.000 63.000 64.000 9.000 11.000 2.349 55.336 °C
Temp LM0 25.750 26.000 26.500 28.250 30.250 33.750 50.000 3.750 7.750 1.731 28.547 °C
Temp LM1 39.500 39.500 40.000 42.000 44.000 44.000 45.000 4.000 4.500 1.029 41.947 °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 40.000 41.000 41.000 43.000 44.000 45.000 49.000 3.000 4.000 1.044 42.727 °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 27.000 27.500 28.000 29.750 31.750 32.750 39.250 3.750 5.250 1.274 29.983 °C
Temp LM16 52.000 52.000 53.000 55.000 62.000 63.000 64.000 9.000 11.000 2.353 55.417 °C
Temp LM17 56.500 57.000 57.500 59.500 62.500 63.500 65.000 5.000 6.500 1.305 59.613 °C
Temp LM18 58.000 59.000 59.000 61.000 70.000 71.000 71.000 11.000 12.000 2.712 61.946 °C
Temp LM19 52.000 52.000 53.000 54.000 61.000 63.000 63.000 8.000 11.000 2.236 54.675 °C
Temp LM2 41.000 41.000 42.000 43.000 45.000 45.000 46.000 3.000 4.000 0.949 43.134 °C
Temp LM20 24.000 25.000 25.000 28.000 30.000 48.000 99.000 5.000 23.000 4.525 28.019 °C
Temp LM21 23.000 24.000 25.000 27.000 30.000 41.000 99.000 5.000 17.000 4.296 27.750 °C
Temp LM22 22.000 23.000 24.000 26.000 29.000 47.000 95.000 5.000 24.000 4.321 26.249 °C
Temp LM23 22.000 23.000 24.000 27.000 29.000 42.000 95.000 5.000 19.000 4.275 26.948 °C
Temp LM24 22.000 23.000 24.000 27.000 29.000 44.000 90.000 5.000 21.000 4.041 26.987 °C
Temp LM3 30.000 30.000 31.000 33.000 34.000 35.000 39.000 3.000 5.000 1.073 32.626 °C
Temp LM4 29.000 29.500 30.000 32.000 34.000 34.500 36.000 4.000 5.000 1.083 31.988 °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 59.000 62.000 63.000 65.000 5.000 6.000 1.318 59.421 °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 27.000 30.000 46.000 99.000 5.000 22.000 4.610 27.807 °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 59.500 62.500 63.500 65.000 5.000 6.500 1.306 59.613 °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) -1.012 -0.567 -0.323 0.040 0.246 0.514 7.967 0.569 1.081 0.302 0.017 ms 16.39 435.1

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 -1.411 -0.672 -0.426 0.044 0.333 0.497 7.815 0.759 1.169 0.327 0.018 ms 10.68 258.6

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 -0.873 -0.050 -0.018 0.046 0.114 0.265 81.822 0.132 0.314 2.279 0.143 ms 28.8 895.4

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 204.17.205.27

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 -2.587 -1.501 -0.664 0.045 0.813 1.808 8.037 1.477 3.309 0.521 0.058 ms 2.868 50.48

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) -80.055 -47.587 -27.139 -1.754 44.904 134.776 301.999 72.043 182.363 30.212 2.728 µs 4.019 30.17

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 0.003 0.005 0.011 0.046 0.090 7.841 0.041 0.087 0.183 0.020 ms 38.62 1529

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 0.006 0.008 0.017 0.036 0.054 5.780 0.028 0.048 0.091 0.021 ms 59.33 3735

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 0.000 0.003 0.005 0.023 0.052 0.083 43.740 0.047 0.080 1.414 0.092 ms 23.96 615.3

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 204.17.205.27

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 0.006 0.013 0.088 0.162 0.206 5.826 0.148 0.200 0.132 0.090 ms 36.3 1548

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) 0.000 0.588 0.983 4.126 12.222 38.988 194.199 11.239 38.400 7.752 5.567 µs 10.4 183.8

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 4.735 4.782 4.866 5.325 6.458 6.618 6.639 1.591 1.836 0.387 5.400 ppm 1.648 5.969
Local Clock Time Offset -0.746 -0.048 -0.027 -0.002 0.045 0.138 7.967 0.072 0.185 0.126 0.005 ms 53.87 3184
Local RMS Frequency Jitter 0.000 0.150 0.208 0.681 3.161 8.074 155.780 2.953 7.924 4.921 1.306 ppb 20.22 490.3
Local RMS Time Jitter 0.547 0.660 0.797 1.375 3.973 13.668 2,904.067 3.176 13.008 98.180 7.347 µs 22.18 541.6
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.000 0.003 0.005 0.011 0.046 0.090 7.841 0.041 0.087 0.183 0.020 ms 38.62 1529
Server Jitter 204.17.205.1 0.000 0.006 0.008 0.017 0.036 0.054 5.780 0.028 0.048 0.091 0.021 ms 59.33 3735
Server Jitter 204.17.205.24 0.000 0.003 0.005 0.023 0.052 0.083 43.740 0.047 0.080 1.414 0.092 ms 23.96 615.3
Server Jitter 204.17.205.27 0.000 0.006 0.013 0.088 0.162 0.206 5.826 0.148 0.200 0.132 0.090 ms 36.3 1548
Server Jitter SHM(0) 0.000 0.588 0.983 4.126 12.222 38.988 194.199 11.239 38.400 7.752 5.567 µs 10.4 183.8
Server Offset 2001:470:e815::8 (spidey.rellim.com) -1.012 -0.567 -0.323 0.040 0.246 0.514 7.967 0.569 1.081 0.302 0.017 ms 16.39 435.1
Server Offset 204.17.205.1 -1.411 -0.672 -0.426 0.044 0.333 0.497 7.815 0.759 1.169 0.327 0.018 ms 10.68 258.6
Server Offset 204.17.205.24 -0.873 -0.050 -0.018 0.046 0.114 0.265 81.822 0.132 0.314 2.279 0.143 ms 28.8 895.4
Server Offset 204.17.205.27 -2.587 -1.501 -0.664 0.045 0.813 1.808 8.037 1.477 3.309 0.521 0.058 ms 2.868 50.48
Server Offset SHM(0) -80.055 -47.587 -27.139 -1.754 44.904 134.776 301.999 72.043 182.363 30.212 2.728 µs 4.019 30.17
Temp /dev/sda 40.000 41.000 41.000 43.000 44.000 45.000 49.000 3.000 4.000 1.043 42.725 °C
Temp /dev/sdb 52.000 52.000 52.000 54.000 61.000 63.000 63.000 9.000 11.000 2.230 54.591 °C
Temp /dev/sdc 53.000 53.000 53.000 54.000 56.000 56.000 60.000 3.000 3.000 0.996 54.044 °C
Temp /dev/sdd 58.000 59.000 59.000 61.000 70.000 71.000 71.000 11.000 12.000 2.712 61.809 °C
Temp /dev/sde 41.000 41.000 42.000 43.000 45.000 45.000 46.000 3.000 4.000 0.953 43.153 °C
Temp /dev/sdf 52.000 52.000 53.000 55.000 62.000 63.000 64.000 9.000 11.000 2.349 55.336 °C
Temp LM0 25.750 26.000 26.500 28.250 30.250 33.750 50.000 3.750 7.750 1.731 28.547 °C
Temp LM1 39.500 39.500 40.000 42.000 44.000 44.000 45.000 4.000 4.500 1.029 41.947 °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 40.000 41.000 41.000 43.000 44.000 45.000 49.000 3.000 4.000 1.044 42.727 °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 27.000 27.500 28.000 29.750 31.750 32.750 39.250 3.750 5.250 1.274 29.983 °C
Temp LM16 52.000 52.000 53.000 55.000 62.000 63.000 64.000 9.000 11.000 2.353 55.417 °C
Temp LM17 56.500 57.000 57.500 59.500 62.500 63.500 65.000 5.000 6.500 1.305 59.613 °C
Temp LM18 58.000 59.000 59.000 61.000 70.000 71.000 71.000 11.000 12.000 2.712 61.946 °C
Temp LM19 52.000 52.000 53.000 54.000 61.000 63.000 63.000 8.000 11.000 2.236 54.675 °C
Temp LM2 41.000 41.000 42.000 43.000 45.000 45.000 46.000 3.000 4.000 0.949 43.134 °C
Temp LM20 24.000 25.000 25.000 28.000 30.000 48.000 99.000 5.000 23.000 4.525 28.019 °C
Temp LM21 23.000 24.000 25.000 27.000 30.000 41.000 99.000 5.000 17.000 4.296 27.750 °C
Temp LM22 22.000 23.000 24.000 26.000 29.000 47.000 95.000 5.000 24.000 4.321 26.249 °C
Temp LM23 22.000 23.000 24.000 27.000 29.000 42.000 95.000 5.000 19.000 4.275 26.948 °C
Temp LM24 22.000 23.000 24.000 27.000 29.000 44.000 90.000 5.000 21.000 4.041 26.987 °C
Temp LM3 30.000 30.000 31.000 33.000 34.000 35.000 39.000 3.000 5.000 1.073 32.626 °C
Temp LM4 29.000 29.500 30.000 32.000 34.000 34.500 36.000 4.000 5.000 1.083 31.988 °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 59.000 62.000 63.000 65.000 5.000 6.000 1.318 59.421 °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 27.000 30.000 46.000 99.000 5.000 22.000 4.610 27.807 °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 59.500 62.500 63.500 65.000 5.000 6.500 1.306 59.613 °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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