On Tue, Apr 25, 2017 at 03:41:12PM +0000, Mace, Kyle P. wrote: > Why would you need multiple phc2sys processes? Shouldn't you only > need one? Shouldn't the command phc2sys -s /dev/ptp0 -c /dev/ptp1 -w > sync the two clocks? And would this still go through the system > clock?
With 'phc2sys -a' and boundary_clock_jbod you don't involve the system clock at all, but everything else Luke said is right. You *will* have "true" BC WRT the protocol, but this BC will introduce relatively large errors, like a dozen usec or so. However, if you can connect your JBODs together with a hardware signal, like the SDPs on the Intel i210, then you can reduce the error to 100 nanoseconds or so, but you will have to write the program to synchronize the group of cards yourself. Still, that is not really the kind of performance you would expect from a proper BC. If you really need long chains, then you should use TCs configured like the Time Aware Bridge (TAB) of 802.1AS. In order to avoid the ill effects of a chain of servos, they let the clock of the TAB run free and calculate the master/local rate ratio in order to correct the residence times. HTH, Richard ------------------------------------------------------------------------------ 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
