ntpviz - Don't plot a line during data absence

Gary E. Miller gem at rellim.com
Sun Oct 23 21:04:51 UTC 2016

Yo Hal!

On Sun, 23 Oct 2016 13:39:32 -0700
Hal Murray <hmurray at megapathdsl.net> wrote:

> gem at rellim.com said:
> >> If the polling interval is X, there may be up to 8X gaps in
> >> peerstats.  
> > Ah, lost me.  Say what?   
> Look at the time differences between samples for an IP Address in
> peerstats.
> If the polling interval is X, there will be a line in rawstats for
> each packet received.  If none are lost, the spacing will be X.

Where X is by default 64 sec, and by default can be ramped up to 1024

So the current line break hack does not plot a line longer than 1024
sec.  Lines of 1024 sec are plotted.  That will not work for folks
setting maxpoll over 1024 sec.

> There is a filter between the raw packets and the ones that come out
> of peerstats.  It has a buffer of the last 8 samples.  It only uses
> the one with the lowest round trip time.  So if you get 8 samples in
> a row with increasing RTT, the last 7 will get saved until the a new
> sample bumps the first one out of the buffer.

Why do we care?   Don't we still get a sample, of some sort, every X?

> Refclocks samples always get through.  I assume it takes new samples
> when the RTT is equal but there might be a simple special case test.

Aren't reclocks local?  Thus no rtt?

Is there anything to try in real plots.

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at rellim.com  Tel:+1 541 382 8588
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