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- To: chrony-users@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-users] Questions about a statistics.log field
- From: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
- Date: Mon, 7 Dec 2020 10:01:57 +0100
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On Thu, Dec 03, 2020 at 08:23:31PM +0000, Frank Wayne wrote:
> Field 4 of statistics.log is the "estimated standard deviation of the measurements from the source (in seconds)", whereas field 6 is the "estimated standard deviation of the offset estimate (in seconds)". Field 6 is apparently the local clock jitter relative to the source, but what is “the measurements from the source” in field 4? Is this an estimate of the source jitter? If so, relative to what?
chronyd keeps a number of measured offsets for each source. The field
4 is the stability of the measurements. That includes the local clock,
network and server clock. The field 6 is the estimated stability of
the final offset calculated from those measurements and which updates
the clock.
The values come from linear regression: data points vs the intercept.
Does that help?
--
Miroslav Lichvar
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