Re: openntpd and ntpq

[Henning Brauer <lists-openbsd@bsws.de>]

* Greg Wooledge <greg@wooledge.org> [2004-09-02 08:04]:
> Now, on the Linux side:
> 
> griffon:/var/log/ntpd$ grep 'offset -' * 2>/dev/null | awk 'BEGIN {max = -999}
> {n++; t += $6; if ($6 > max) max = $6; if ($6 < min) min = $6;} END {print "n
> " n " avg " t/n " max " max " min " min}'
> n 21 avg -4.29011 max -0.002445 min -12.764331

> griffon:/var/log/ntpd$ grep 'offset [0-9]' * 2>/dev/null | awk 'BEGIN {min =
> 99999} {n++; t += $6; if ($6 > max) max = $6; if ($6 < min) min = $6;} END
> {print "n " n " avg " t/n " max " max " min " min}'
> n 8113 avg 0.390865 max 1.075856 min 0.004901
> 
> This is quite representative of what I see whenever I check the logs by
> eyeball.  The offset tends to swing wildly in the 0.1 to 0.7 range, and
> occasionally goes over a second.
> 
> The Linux machine's performance under OpenNTPD is quite bad, really,
> considering that all it needs to do is sync to the OpenBSD box over a
> 100 Mbps LAN.  I don't fully trust it at this point, which is why I keep
> the logfiles open and watch them periodically.

as the logs show, we periodically call adjtime() to, well, adjust for 
the offset. and it doesn't get better - we keep calling adjtime() with 
offsets in the same range, and it does not seem to do what it is 
suppsoed to, adjust the tick frequency slightly to compensate for the 
offset. Now, I don't see much of a chance for adjtime() _not_ beeing 
the culprit here, it pretty much seems broken on your machine.

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