[ntp:questions] Performance estimation

David Taylor david-taylor at blueyonder.co.uk.invalid
Mon Jun 15 14:38:15 UTC 2020

On 15/06/2020 08:33, Miroslav Lichvar wrote:
> On 2020-06-14, David Taylor <david-taylor at blueyonder.co.uk.invalid> wrote:
>> When using the ntpq -crv command, which is the better measure of system
>> performance - clk_jitter or sys_jitter?  I've look for the definitions
>> and I'm thinking sys_jitter but perhaps someone could please remind me
>> of the difference?
> clk_jitter seems to be the jitter of the system clock as it is being
> updated with offsets, and sys_jitter seems to be the jitter of the
> selected peer, or the combined peers after clustering.
> https://www.eecis.udel.edu/~mills/ntp/html/cluster.html


[Been trying to send through e-mail to ntp-questions, but anything I 
send gets rejected!]

Thanks, Miroslav.  Right!  I'm not sure which I should be measuring so I
plotted both:


Blue is system jitter, green is clock jitter.

The lightly-loaded Raspberry Pi cards are all showing low numbers of 
jitter, and it would be really useful to get that in more than three 
decimal places of milliseconds.

Web: http://www.satsignal.eu

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