Sorry forgot to include this, read section 5.1.3.3 it descibes how to min/max poll are used http://www.ntp.org/ntpfaq/NTP-s-algo.htm#Q-ALGO-CLK-UPD
On Tue, May 14, 2013 at 5:55 PM, Chris Albertson <[email protected]>wrote: > Long intervals are a good thing. > > What NTP does is discipline the rate of the clock. So lets say you > wanted to adjust the rate of some mechanical clock. You first set it > as good as you can then wait an hour and see if it gained or lost > time. then you move the fast/slow lever on the back of the clock. > After a few hours the clock is pletty good and you have to wait a full > day to see an error. Then as you zero in on the exact rate setting it > takes a week to see any error. > > This is kind of what NTP is doing if you want to correct out tiny > errors in the clock rate you have to wait a long time > > That said I think there is a "maxpoll" parameter you can add o the > /etc/conf file. > > But why? > > Maybe not you, but I think some people think "Oh my, NTP is not > checking the time very often. It must not be accurate." That is > thinking backwards, you need the long poll interval to see small > errors in rate. But this assumes a stable local clock. NTP balances > this. > > > > On Tue, May 14, 2013 at 5:30 PM, Miguel Barbosa Gonçalves <[email protected]> > wrote: > > Hi! > > > > I am trying to figure out why NTP takes so long to react to oscillator > > changes... I want it to track the PPS from a Trimble Acutime as closely > > as possible. > > > > When checking ntptime on startup I see that the NTP daemon is using > > PLL and starts the adjustment interval at 8 s. It then increases to > > 16, 32, 64, 128 and stops at 256. > > > > I read in the documentation that this limit should be 128 but is now 256. > > > > --- start from http://www.ntp.org/ntpfaq/NTP-s-config-adv.htm --- > > intervals 57 says that there were 57 calibration intervals. When PPS > > pulses are arriving, this number should increase. Each frequency > > adjustment requires a good calibration interval. The length of the > > current calibration interval can be found as interval 128 s (128 > > seconds is the default maximum length). Remaining numbers count > > abnormal conditions as explained below. > > --- end --- > > > > How can I make it stop earlier? At 64 s for example? > > > > Any ideas? > > > > TIA, > > Miguel > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > -- > > Chris Albertson > Redondo Beach, California > -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
