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Re: PSA: Clock drift and pkgin



On Thu, 2023-12-21 12:49:06 +0100, Johnny Billquist <bqt%softjar.se@localhost> wrote:
> On 2023-12-21 12:14, Jan-Benedict Glaw wrote:
> > On Thu, 2023-12-21 10:44:22 +0000, Maciej W. Rozycki <macro%orcam.me.uk@localhost> wrote:
> > > On Wed, 20 Dec 2023, Maciej W. Rozycki wrote:
> 
> [...]
> 
> > Looking at the numbers, I wonder about multiple issues here. Why did
> > the jitter values rise up that much, while the delay keeps its value?
> 
> Unless I remember wrong, delay is merely how long it takes for packets to
> travel back and forth to the ntp server. So it has no relation to jitter or
> offset. It would rather be weird if delay suddenly started changing.

delay is ... "ping time".  jitter is a measure of how much ping times
differ to each other.

It is kind of unreasonable that the jitter changes so much while delay
seems to be always in the same region.

> > ...and finally: Why didn't ntpd react with increasing the poll
> > interval?
> 
> It's already at the max poll interval in all those reports.

Yeah, sorry, that was misleading. I ment to decrease it, increasing
the poll frequency.

> ntp starts out with an interval of 64s, and backs off to 1024 eventuall,
> over time, if things are stable. In this case things aren't stable, but it
> seems to never have locked on to anything. So it's just been drifting the
> whole time, it looks to me.

That's why I was interested in how the pll freq changed. The 1024sec
poll interval however is an indicator for a successful lock.

MfG, JBG

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