Hi The top of my list for “new NTP” would be to bring the 1588 hardware packet time tagging into the NTP code base. There’s a pretty good base of hardware out there that tags. It should help things on a loaded system.
Bob > On Oct 20, 2014, at 3:41 PM, Poul-Henning Kamp <[email protected]> wrote: > > -------- > In message <60CC0E0EEEE34928B664249EAC88407F@pc52>, "Tom Van Baak" writes: >>> http://phk.freebsd.dk/time/20141018.html >> >> PHK, >> >> This is the best news I've heard in a long time; an overhaul of NTP! > > Indeed :-) > >> Instead of tweaking GPSDO algorithms or tuning parameters and >> having to wait days to see if it works or not, the idea was to >> "replay" pre-recorded 1PPS data and pre-recorded oscillator data >> into the PLL. This means one can test any new design change in a >> GPSDO in a matter of seconds instead of days. >> >> So the question is -- could you do the same for NTP? > > Well, first of all it's not days any longer. My proto-PLL wrangles > the clock phase in a matter of seconds and frequency in a few > minutes. Some of the (really) old NTP assumptions and metrics no > longer hold, revisiting them opens up a lot of parameter space. > > Second, I'm already doing such simulations, and the ability to > do that is part of the design basis of what I'm doing. > > I spent a month of my NTP-time trying to resurrect the "SIM" code in > ntpd, in order to get some kind of reproducible test-bench going and > in the end I concluded that 100k lines of code is not the way forward. > > My current plan is to release a brand new client-only NTP daemon > with a decent PLL and high attack resistance before X-mas and then > work from there to one or two other programs: NTP-slave server (ie: > stratum 2..14) and a NTP-master/stratum 1 server. > > All along the way, the intent is to try to pull PTP into this also, > since there is no material (ie: only protocol) difference between > a NTP and PTP timekeeping program, and the user shouldn't need to > notice the difference. > > More as it happens. > > The "mini-blog" entries I've started will happen every so often > when there is some progress to report or interesting data to > present. > > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > [email protected] | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > _______________________________________________ > 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. _______________________________________________ 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.
