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- To: chrony-users@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-users] Measuring clock offset results
- From: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
- Date: Wed, 19 Jul 2023 16:17:12 +0200
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On Wed, Jul 12, 2023 at 09:52:11AM -0700, Thangalin wrote:
> https://ibb.co/album/1Z824p
>
> Are there any other ways we could help chronyd stay below 20 microseconds
> (e.g., optimized build) that may have been overlooked (besides using GPIO)?
If you zoom on those spikes and see that they are just single
samples, it's probably not an error of the clock, but rather a
measurement error (e.g. due to interrupt delays). You should implement
some filtering in your program, e.g. use the median value from a
number of consecutive samples (e.g. 5). That's what both ntpd and
chronyd are doing with the data they get.
--
Miroslav Lichvar
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