In 3 weeks I have 2 connected to a GPS with PPS, I'll publish the results here. It is great stuff, these RPIs.
On Sun, May 26, 2013 at 09:30:47AM -0700, Chris Albertson wrote: > NTP does not really "sync" to a server. What it does is "use the set > of reference clocks that pas the clock selection criteria". THere is > an algorithm that determines if a reference clock is reasonable or > not. A reference clock can be a GPS or another NTP server or a cell > phone service or any of a dozen other things but GPS and other servers > are by far the most common. > > Your RPI is three leves removed from a GPS. It is operating as > "stratum 3" the second RPI is stratum 2. Both are doing really good > for using a networked ref. clock. I would not blain the RPI. If you > are doing better than a millisecond with no local PPS it is good. > > On Sun, May 26, 2013 at 9:15 AM, folkert <[email protected]> wrote: > >> > Besides I got them to run NTP and they're too jittery for my taste. > >> > >> How good/bad were they? > >> What were you using for a time source? Does it have PPS support? > > > > Here's ntpq -c pv for one of my RPIs after 25 days of uptime: > > > > associd=0 status=0615 leap_none, sync_ntp, 1 event, clock_sync, > > version="ntpd [email protected] Fri May 18 20:30:57 UTC 2012 (1)", > > processor="armv6l", system="Linux/3.8.10+", leap=00, stratum=3, > > precision=-20, rootdelay=25.184, rootdisp=73.646, refid=83.98.201.134, > > reftime=d54cac1f.18aa9126 Sun, May 26 2013 17:43:27.096, > > clock=d54cb273.b755933f Sun, May 26 2013 18:10:27.716, peer=34195, > > tc=10, mintc=3, offset=0.182, frequency=-47.006, sys_jitter=0.377, > > clk_jitter=0.558, clk_wander=0.051 > > > > Hmmm found out that it syncs to random hosts on the internet. > > > > Ok an other one which syncs against an other pc with PPS (and a few > > others): > > > > folkert@weerpi ~ $ ntpq -c rv > > associd=0 status=0615 leap_none, sync_ntp, 1 event, clock_sync, > > version="ntpd [email protected] Fri May 18 20:30:57 UTC 2012 (1)", > > processor="armv6l", system="Linux/3.8.10+", leap=00, stratum=2, > > precision=-20, rootdelay=0.807, rootdisp=7.669, refid=192.168.64.100, > > reftime=d54cb1e1.9d6e8f07 Sun, May 26 2013 18:08:01.614, > > clock=d54cb2e4.7d1cdae3 Sun, May 26 2013 18:12:20.488, peer=41936, tc=9, > > mintc=3, offset=0.220, frequency=-31.405, sys_jitter=0.647, > > clk_jitter=0.074, clk_wander=0.003 > > > > folkert@weerpi ~ $ uptime > > 18:12:25 up 15 days, 3:48, 1 user, load average: 0.12, 0.17, 0.15 > > > > > > Folkert van Heusden > > > > -- > > Multitail est un outil permettant la visualisation de fichiers de > > journalisation et/ou le suivi de l'exécution de commandes. Filtrage, > > mise en couleur de mot-clé, fusions, visualisation de différences > > (diff-view), etc. http://www.vanheusden.com/multitail/ > > ---------------------------------------------------------------------- > > Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com > > _______________________________________________ > > 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 > _______________________________________________ > 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. Folkert van Heusden -- www.TrustedTimestamping.com is a service that enables you to show that at a certain point in time, you had access to a hash-value reflecting the contents of a file (this file can be a word document, a jpeg image, everything). ---------------------------------------------------------------------- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com _______________________________________________ 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.
