[PATCH 0/5] Fix ntpd to not poll frequently

Miroslav Lichvar mlichvar at redhat.com
Wed Oct 1 12:22:07 UTC 2014


On Wed, Oct 01, 2014 at 01:28:11AM +0200, Denys Vlasenko wrote:
> On Wed, Oct 1, 2014 at 12:50 AM, Denys Vlasenko > It so happens that I
> caught a similar behavior in real world

> Do you see something we do wrongly here?
> 
> Should we change the logic somehow to raise poll interval?
> Surely, with round-trip delay of ~0.3 seconds
> things won't be better with short interval than with longer one...

I think the problem is that poll is shortened with large offsets even
when the jitter is large in the POLLDOWN_OFFSET check, so the
normal poll adjusting code doesn't have a chance to increase it.

Also, the offset would be probably much more stable in this case if
the filter used only the sample with shortest distance from last
eight, as it's done in the reference implementation.

-- 
Miroslav Lichvar


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