unruh wrote:
On 2011-04-19, David Lord <[email protected]> wrote:
unruh wrote:
On 2011-04-19, David Lord <[email protected]> wrote:
.....
When I first compared chrony with ntpd there was no contest
but more recent experiments with chrony had periods of
severe instability much worse than ntpd.
More recent means what? What version of chrony? (there was a bug found
in the past two weeks that was introduces a few months ago which did
result in instability)
More recent than November 2009.
Probably between Dec 2009 and Jan 2010 and p4x2400c.
chrony 1.23
OK well before that change.
P4X2666 with chrony
<http://www.lordynet.org.uk/mrtg/stats/>
Not at all sure what I am supposed to see. I have no idea what the graph
axes represent? What is 1.1k
X-axis is in hours
Y-axis is offset in us so 1.1k = 1100us
WOW. What kind of network are you attached to? Even on an ADSL link
through the phone company, I
was getting in the tens of usec (not ms) as the offsets of chrony.
(checked by a gps receiver attached to the local computer).
I'm on ADSL-1 with 2 Mbit/s down and 288 kbit/s up. Latency
is what BT delivers and has been as low as 12ms up to 50ms or
more but mostly it's about 18ms to nearest sites (when exchange
gets near capacity the latency jumps up by 15ms or more same as
when interleave is enabled on ADSSL-2).
Although the peaks of the graph are at about 1ms the stats
have "System time" mostly being in the 10s of usec.
And what is it about the graph that makes you believe you are seeing
instability.
There is nothing in that session but later graphs now
wrapped (as in loops around after a year) showed much
worse offset variations than the systems using ntpd at
which point I went back to using ntpd.
David
Next experiment is to couple up the GPS again but if you
click on the ME6000 in the current stats the yearly graph
for Sep/Oct/Nov was when I last had the gps connected.
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