NTPsec

Backup/Meinberg

Report generated: Sun Sep 20 15:43:00 2026 UTC
Start Time: Sun Sep 13 15:43:00 2026 UTC
End Time: Sun Sep 20 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 -123.545 -63.435 -15.183 -2.154 19.460 92.087 236.065 34.643 155.522 20.821 0.209 µs 2.763 32.39
Local Clock Frequency Offset 11.002 11.039 11.130 11.293 11.639 11.683 11.777 0.509 0.644 0.153 11.339 ppm 0.5806 2.72

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 0.347 0.423 0.490 0.756 3.225 8.717 18.863 2.735 8.294 1.496 1.121 µs 5.651 42.5

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 0.049 0.077 0.111 0.442 2.066 6.121 11.923 1.955 6.044 1.061 0.702 ppb 5.072 35.15

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 -123.545 -63.435 -15.183 -2.154 19.460 92.087 236.065 34.643 155.522 20.821 0.209 µs 2.763 32.39

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 11.002 11.039 11.130 11.293 11.639 11.683 11.777 0.509 0.644 0.153 11.339 ppm 0.5806 2.72
Temp /dev/sda 63.000 63.000 63.000 65.000 66.000 67.000 74.000 3.000 4.000 1.035 64.894 °C
Temp /dev/sdb 45.000 45.000 46.000 46.000 51.000 52.000 52.000 5.000 7.000 1.575 47.071 °C
Temp /dev/sdc 56.000 56.000 56.000 58.000 60.000 61.000 65.000 4.000 5.000 1.351 57.755 °C
Temp /dev/sdd 69.000 69.000 69.000 71.000 74.000 75.000 80.000 5.000 6.000 1.411 70.930 °C
Temp /dev/sde 49.000 49.000 49.000 50.000 56.000 56.000 56.000 7.000 7.000 1.821 50.709 °C
Temp /dev/sdf 46.000 47.000 47.000 48.000 53.000 53.000 54.000 6.000 6.000 1.638 48.530 °C
Temp LM0 28.000 28.000 28.500 29.250 31.750 35.750 43.000 3.250 7.750 1.276 29.586 °C
Temp LM1 40.000 40.000 40.500 41.500 43.000 43.500 45.000 2.500 3.500 0.632 41.584 °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 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °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 29.250 29.250 29.750 30.500 32.500 34.250 39.500 2.750 5.000 0.984 30.780 °C
Temp LM16 47.000 47.000 47.000 48.000 53.000 53.000 54.000 6.000 6.000 1.648 48.566 °C
Temp LM17 59.500 60.000 60.000 61.000 65.000 66.000 67.500 5.000 6.000 1.167 61.520 °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 45.000 45.000 46.000 46.000 51.000 52.000 52.000 5.000 7.000 1.588 47.079 °C
Temp LM2 49.000 49.000 49.000 50.000 56.000 56.000 56.000 7.000 7.000 1.828 50.737 °C
Temp LM20 26.000 27.000 28.000 29.000 32.000 51.000 80.000 4.000 24.000 3.657 29.434 °C
Temp LM21 25.000 27.000 27.000 29.000 31.000 46.000 80.000 4.000 19.000 3.402 29.235 °C
Temp LM22 24.000 24.000 25.000 26.000 29.000 46.000 71.000 4.000 22.000 3.473 26.783 °C
Temp LM23 25.000 26.000 26.000 28.000 31.000 48.000 72.000 5.000 22.000 3.396 28.525 °C
Temp LM24 25.000 25.000 26.000 27.000 30.000 44.000 66.000 4.000 19.000 3.115 27.753 °C
Temp LM3 32.000 32.000 33.000 33.000 35.000 36.000 40.000 2.000 4.000 0.754 33.471 °C
Temp LM4 30.500 30.500 31.000 32.000 34.000 34.500 35.500 3.000 4.000 0.947 32.193 °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 26.500 27.000 27.500 28.500 31.000 52.500 75.000 3.500 25.500 3.615 29.073 °C
Temp LM7 59.000 60.000 60.000 61.000 65.000 66.000 67.000 5.000 6.000 1.143 61.344 °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 27.000 27.000 27.000 29.000 31.000 51.000 75.000 4.000 24.000 3.685 29.295 °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 60.000 60.000 61.000 65.000 66.000 67.500 5.000 6.000 1.172 61.513 °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) -782.379 -505.758 -150.266 35.207 199.254 382.061 502.925 349.520 887.819 128.309 24.361 µs -1.409 11.86

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 -2.448 -1.175 -0.298 0.039 0.386 0.582 0.706 0.684 1.757 0.283 0.012 ms -3.174 24.27

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 -132.125 -47.973 -19.257 55.814 88.186 167.296 308.461 107.443 215.269 36.181 50.126 µs 0.3981 9.202

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 -495.113 -128.200 -21.184 48.481 118.798 240.560 576.910 139.982 368.760 59.831 48.213 µs -0.4 24.04

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) -123.546 -63.436 -15.184 -2.155 19.461 92.088 236.066 34.645 155.524 20.821 0.209 µs 2.763 32.38

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) 1.208 3.106 4.994 20.982 79.554 105.871 182.901 74.560 102.765 24.989 29.385 µs 1.312 4.556

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 1.855 5.473 8.596 20.963 44.108 74.505 247.152 35.512 69.032 14.615 23.617 µs 4.607 49.22

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 0.953 3.254 5.200 22.607 61.459 87.939 129.843 56.259 84.685 17.140 25.410 µs 1.79 7.527

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 1.888 7.128 16.128 109.906 178.768 208.486 286.254 162.640 201.358 48.089 105.720 µs -0.2036 2.726

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) 0.111 0.327 0.511 1.700 7.194 36.083 107.767 6.683 35.756 6.441 3.054 µs 7.729 80.5

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 11.002 11.039 11.130 11.293 11.639 11.683 11.777 0.509 0.644 0.153 11.339 ppm 0.5806 2.72
Local Clock Time Offset -123.545 -63.435 -15.183 -2.154 19.460 92.087 236.065 34.643 155.522 20.821 0.209 µs 2.763 32.39
Local RMS Frequency Jitter 0.049 0.077 0.111 0.442 2.066 6.121 11.923 1.955 6.044 1.061 0.702 ppb 5.072 35.15
Local RMS Time Jitter 0.347 0.423 0.490 0.756 3.225 8.717 18.863 2.735 8.294 1.496 1.121 µs 5.651 42.5
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 1.208 3.106 4.994 20.982 79.554 105.871 182.901 74.560 102.765 24.989 29.385 µs 1.312 4.556
Server Jitter 204.17.205.1 1.855 5.473 8.596 20.963 44.108 74.505 247.152 35.512 69.032 14.615 23.617 µs 4.607 49.22
Server Jitter 204.17.205.24 0.953 3.254 5.200 22.607 61.459 87.939 129.843 56.259 84.685 17.140 25.410 µs 1.79 7.527
Server Jitter 204.17.205.27 1.888 7.128 16.128 109.906 178.768 208.486 286.254 162.640 201.358 48.089 105.720 µs -0.2036 2.726
Server Jitter SHM(0) 0.111 0.327 0.511 1.700 7.194 36.083 107.767 6.683 35.756 6.441 3.054 µs 7.729 80.5
Server Offset 2001:470:e815::8 (spidey.rellim.com) -782.379 -505.758 -150.266 35.207 199.254 382.061 502.925 349.520 887.819 128.309 24.361 µs -1.409 11.86
Server Offset 204.17.205.1 -2.448 -1.175 -0.298 0.039 0.386 0.582 0.706 0.684 1.757 0.283 0.012 ms -3.174 24.27
Server Offset 204.17.205.24 -132.125 -47.973 -19.257 55.814 88.186 167.296 308.461 107.443 215.269 36.181 50.126 µs 0.3981 9.202
Server Offset 204.17.205.27 -495.113 -128.200 -21.184 48.481 118.798 240.560 576.910 139.982 368.760 59.831 48.213 µs -0.4 24.04
Server Offset SHM(0) -123.546 -63.436 -15.184 -2.155 19.461 92.088 236.066 34.645 155.524 20.821 0.209 µs 2.763 32.38
Temp /dev/sda 63.000 63.000 63.000 65.000 66.000 67.000 74.000 3.000 4.000 1.035 64.894 °C
Temp /dev/sdb 45.000 45.000 46.000 46.000 51.000 52.000 52.000 5.000 7.000 1.575 47.071 °C
Temp /dev/sdc 56.000 56.000 56.000 58.000 60.000 61.000 65.000 4.000 5.000 1.351 57.755 °C
Temp /dev/sdd 69.000 69.000 69.000 71.000 74.000 75.000 80.000 5.000 6.000 1.411 70.930 °C
Temp /dev/sde 49.000 49.000 49.000 50.000 56.000 56.000 56.000 7.000 7.000 1.821 50.709 °C
Temp /dev/sdf 46.000 47.000 47.000 48.000 53.000 53.000 54.000 6.000 6.000 1.638 48.530 °C
Temp LM0 28.000 28.000 28.500 29.250 31.750 35.750 43.000 3.250 7.750 1.276 29.586 °C
Temp LM1 40.000 40.000 40.500 41.500 43.000 43.500 45.000 2.500 3.500 0.632 41.584 °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 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °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 29.250 29.250 29.750 30.500 32.500 34.250 39.500 2.750 5.000 0.984 30.780 °C
Temp LM16 47.000 47.000 47.000 48.000 53.000 53.000 54.000 6.000 6.000 1.648 48.566 °C
Temp LM17 59.500 60.000 60.000 61.000 65.000 66.000 67.500 5.000 6.000 1.167 61.520 °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 45.000 45.000 46.000 46.000 51.000 52.000 52.000 5.000 7.000 1.588 47.079 °C
Temp LM2 49.000 49.000 49.000 50.000 56.000 56.000 56.000 7.000 7.000 1.828 50.737 °C
Temp LM20 26.000 27.000 28.000 29.000 32.000 51.000 80.000 4.000 24.000 3.657 29.434 °C
Temp LM21 25.000 27.000 27.000 29.000 31.000 46.000 80.000 4.000 19.000 3.402 29.235 °C
Temp LM22 24.000 24.000 25.000 26.000 29.000 46.000 71.000 4.000 22.000 3.473 26.783 °C
Temp LM23 25.000 26.000 26.000 28.000 31.000 48.000 72.000 5.000 22.000 3.396 28.525 °C
Temp LM24 25.000 25.000 26.000 27.000 30.000 44.000 66.000 4.000 19.000 3.115 27.753 °C
Temp LM3 32.000 32.000 33.000 33.000 35.000 36.000 40.000 2.000 4.000 0.754 33.471 °C
Temp LM4 30.500 30.500 31.000 32.000 34.000 34.500 35.500 3.000 4.000 0.947 32.193 °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 26.500 27.000 27.500 28.500 31.000 52.500 75.000 3.500 25.500 3.615 29.073 °C
Temp LM7 59.000 60.000 60.000 61.000 65.000 66.000 67.000 5.000 6.000 1.143 61.344 °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 27.000 27.000 27.000 29.000 31.000 51.000 75.000 4.000 24.000 3.685 29.295 °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 60.000 60.000 61.000 65.000 66.000 67.500 5.000 6.000 1.172 61.513 °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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