The stratum indicates how many hops away from a computer with an attached reference clock we are. Such a computer is a stratum-1 computer, so the computer in the example is two hops away (i.e. foo.example.net is a stratum-2 and is synchronised from a stratum-1). Maximum usable stratum is 14 and maximum value is 15, indicating that no valid reference clock available. Normally for undisciplined RTC clock (example PC internal clock chip) value of 10 is used.

In normal operation, chronyd by default never steps the system clock, because any jump in the time can have adverse consequences for certain application programs. Instead, any error in the system clock is corrected by slightly speeding up or slowing down the system clock until the error has been removed, and then returning to the system clock’s normal speed. A consequence of this is that there will be a period when the system clock (as read by other programs) will be different from chronyd's estimate of the current true time. This graph shows the difference due to this effect.

This is the estimated local offset on the last clock update. A positive value indicates the local time (as previously estimated true time) was ahead of the time sources.

This is a long-term average of the offset value. The root mean square (RMS) is defined as the square root of the mean square (the arithmetic mean of the squares of a set of numbers). The RMS is also known as the quadratic mean.

This graph shows the margin of error in the measurement of PPS (pulse per second source, from GPS timing module). Positive offsets indicate that the local clock is ahead of the source. All values are in nano seconds.

This graph shows the Root Delay time from GPS module. All values are in nano seconds.