[EMAIL PROTECTED] (David McConnell) writes: >Hi
>We are using Linux ntpd with GPS/PPS reference clock to discipline the time >on our systems. >Our application requires good time accuracy (better than 5ms) but it also >needs to get there quickly (as quickly as possible, but ideally taking no >more than about 15 minutes). >(The Linux/ntpd is running on a remote embedded device that is frequently >restarted - possibly once a day or so - so we cant wait hours for >convergence). >Currently ntpd can take hours to achieve the desired acuracy. Are you using the -g option? What is the poll interval for your gps clock? (Use 4 whcih I think is the default for gps clocks.) ntp is NOT designed for rapid convergence, but on a gps clock with poll interval 4 and -g it sure should be better than hours. >So, the question is simple - is there any way to significantly speedup the >convergence of ntpd (using GPS/PPS reference clock)? >We would be prepared to compromise somewhat on accuracy and jitter. >(Currently accuracy and jitter values are excellent with jitter as low as 1 >microsecond and accuracy better than 10 uS but it can take a day or two to >get there). >It does not seem unreasonable to expect that the ntpd could achieve the >required accuracy within 15 minutes or so - but nothing we have tried seems >to work. >Have tried modifying some of the tinker values, but we dont really >understand what they all do - and have not really had any success. >So to summarise: >1) Is it possible to speedup ntpd convergence (using GPS/PPS reference >clock)? >2) If so, how - and what are the tradeoffs? >Any help appreciated >David _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
