diff --git a/doc/chronyc.adoc b/doc/chronyc.adoc index 1eaf21f..0478529 100644 --- a/doc/chronyc.adoc +++ b/doc/chronyc.adoc @@ -180,15 +180,19 @@ stratum-2 and is synchronised from a stratum-1). This is the time (UTC) at which the last measurement from the reference source was processed. *System time*::: -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 (which it -reports to NTP clients when it is operating as a server). The value reported -on this line is the difference due to this effect. +This is the current offset between the NTP clock and system clock. The NTP +clock is a software (virtual) clock maintained by *chronyd*, which is +synchronised to the configured time sources and provides time to NTP clients. +The system clock is synchronised to the NTP clock. To avoid steps in the +system time, which might have adverse consequences for certain applications, +the system clock is normally corrected only by speeding up or slowing down (up +to the rate configured by the <> +directive). If the offset is too large, this correction will take a very long +time. A step can be forced by the <> command, or the +<> directive in the configuration file. ++ +Note that all other offsets reported by *chronyc* and most offsets in the log +files are relative to the NTP clock, not the system clock. *Last offset*::: 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