On Tue, Apr 04, 2017 at 06:52:21PM +1000, David Mirabito wrote: > Is it safe to assume, that given a crappy PTP network ptp4l would just > degrade to ntp-like performance at worst? Or are there some other > thresholds or sanity checks which would cause it to throw in the towel in > situations where NTP would keep trucking, being designed for such > situations and necessarily more robust?
No, NTP would generally perform better in non-ideal conditions (e.g. busy network using switches without PTP support), but PTP should still work. What you describe looks like a bug to me. > Mar 19 09:06:54 user.info phc2sys: [1337052.328] reconfiguring after port > state change > Mar 19 09:06:54 user.info phc2sys: [1337052.328] selecting CLOCK_REALTIME > for synchronization > Mar 19 09:06:54 user.info phc2sys: [1337052.328] selecting eth2 as the > master clock > Mar 19 09:06:56 user.warning ptp4l: [1337054.329] clockcheck: clock jumped > backward or running slower than expected! > Mar 19 09:06:56 user.notice ptp4l: [1337054.331] port 1: SLAVE to > UNCALIBRATED on SYNCHRONIZATION_FAULT > Mar 19 09:06:56 user.warning ptp4l: [1337054.562] clockcheck: clock jumped > forward or running faster than expected! > Is this a possible failure mode of a network / master that is just too poor > to survive? A broken master shouldn't trigger the clockcheck messages on slaves. I suspect the phc2sys process is adjusting/stepping the PHC when it shouldn't, possibly triggering some feedback loop between ptp4l and phc2sys. What HW/driver and linuxptp version is this? Can you please post your ptp4l config and command-line options used for ptp4l and phc2sys? Having full logs with measurements (-l 6) might help too. -- Miroslav Lichvar ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
