Re: [chrony-users] Nanosecond precision with refclock SOCK |
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- To: chrony-users@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-users] Nanosecond precision with refclock SOCK
- From: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
- Date: Mon, 15 Jan 2024 15:14:05 +0100
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On Mon, Jan 15, 2024 at 08:56:41PM +0700, James Clark wrote:
> There are three successive cases around a positive leap second:
>
> - the true time is before the start of the leap: in this case the
> difference in the POSIX system times will be 3
> - the true time is after the leap has finished but system time is before
> the leap: in this case the difference in the POSIX times will be 2 (because
> 1 second of the difference is a leap second and so ignored)
> - the system time is after the leap is finished: in this case the
> difference will again be 3
>
> Are you saying that chrony expects the offset to jump around like this
> (even though there is no change in the amount by which the clock needs to
> be corrected)?
It will ignore the 2-second offset because it's in that 10-second
interval around the leap.
If the offset was larger than 10/11 seconds and the clock couldn't be
corrected by step, it would get the one-second error in measurements
accepted before getting close to the leap.
--
Miroslav Lichvar
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