On Wed, Dec 26, 2018 at 11:33:32AM -0600, Keith Squier wrote: > So one idea would be to > configure ntpd/chronyd to take the PPS and then my application can pass the > time using SHM. ntpd/chronyd can do their thing to smooth out and properly > adjust the system clock. With the system clock being disciplined, I can > then use phc2sys to synchronize the PHC to the system clock using something > like "-s CLOCK_REALTIME -c eth0". (Do I need to use the -d option to pass > /dev/pps0?) > > Are there any downsides to this?
Yes, you are chaining two clock servos, one in ntpd and a second one in phc2sys. That is an unnecessary source of error for your PTP clients. Of course, you can make your GM in this way if you want to, but it would be better to feed the PPS signal directly into your PHC (assuming it can time stamp external input signals). You would need to write the PPS servo yourself, but you could adapt the ntpd or ptp4l servos for this purpose. HTH, Richard _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
