On 2011-04-20, David Lord <[email protected]> wrote: > 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.
Not sure what you mean by that. What I mean is , what are the measured offsets? (Of course if you have a GPS PPS that you could use as a reference-- not a source of time-- that would make much clearer what is going on.) > >> >> 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. Certainly not my experience. And the lack of evidence makes it hard to fix any problems if they are there. _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
