On Wed, Nov 16, 2011 at 00:27, Dave Hart <[email protected]> wrote: > FUDGEFAC is 0.1. The code does not match the docs, which say all > refclocks are calibrated to match the source marked prefer. What > actually is done is: only if the sys_peer is the ATOM driver (22), > nudge every other non-ATOM refclock's fudge time1 by -10% of its > current offset from the system clock. Over time it will settle down > with the needed fudge time1 value in effect for each non-ATOM refclock > to agree with the ATOM driver. > > To use it with the current implementation, you must have a PPS source > and you must configure the ATOM driver for that PPS source (as opposed > to using, for example NMEA's PPS support), then ntpd will > automatically determine the fudge time1 value for the remaining > refclock(s). You can ensure the clock(s) you want to calibrate aren't > used by adding noselect to their server lines. You can montior fudge > time1 using ntpq's cv ASSOCID/cv &X (X is 1-based index of refclock in > billboard/as output, ASSOCID would be from ntpq -c as). Once it's > settled configure the fudge time1 for each in ntp.conf, remove the > "enable calibrate" and any "noselect"s added for calibration, and if > needed revert to your original PPS configuration. Upon restart, all > the refclocks should now agree with the PPS.
This implementation was introduced 9-Sep-2007 for 4.2.5p74. Prior to that, refclocks could be calibrated against any source. Cheers, Dave Hart _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
