On Tue, 24 Feb 2015 21:33:49 +0000, Keller, Jacob E wrote: > I do not believe Jiri is right. I ran a similar config and it appeared > to work fine, without crazy clock jumping. Chronyd simply took the SHM > reference and tuned the system clock over time, because the ntpshm > servo presents itself to the ntp daemon.
You're right and I'm not. The ntpshm servo always sets the SERVO_UNLOCKED state in the sample() callback, thus it never sets any clock. I didn't know that and I dislike that very much. This is a gross hack. Not mentioning it's not documented in the man page. Miroslav, any chance to improve this to be better understandable to users? From the user point of view, the shm is just another time source. In the code, it could be implemented as a fake clock (as you need at least two clocks for phc2sys to do anything) driven by this special servo. Requiring the user to add a random second clock for this to work (be it a system clock or a different PHC) is very confusing. This still won't allow things like a two-PHC boundary clock with NTP synchronization. For this, we'll need to be able to specify per-clock servos. The ntpshm servo then will drive only the fake clock. Jiri -- Jiri Benc ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
