On Thu, Feb 26, 2015 at 01:31:33PM -0800, Gary E. Miller wrote: > This is the I210: > > #x SHM2 0 4 377 8 -212ms[ -212ms] +/- > 1000ns > > This is a local reference clock over NTP > > ^* spidey.rellim.com 1 8 377 135 +10us[ +14us] +/- > 182us > > I do not have time now, but I have directly connnected a PPS source > previously and the spidey time is correct. Spidey is PPS synced (jitter > ~200 nSec) and my local grand master. Other timestamp software slaves > of spidey see about 6 uSec or less of jitter and small offset. So spidey > is rock solid in the uSec range.
I don't see any problems like that on my testing system with i210 (kernel 3.17.8). The PTP time with HW timestamping agrees with an NTP source (synchronized by GPS PPS) to few microseconds. > > One other tidbit is that I210 supports EEE, which can affect jitter, > > although I wouldn't expect it on that level. You can try turning this > > off via ethtool (ethtool --set-eee ethX eee off) to see if that helps. > > I'll try that next week. But my problem is offset. Plus chronyd doing > somthing wrong as no way there is 1000 nSec jitter, I can see the offset > jumping around! The default precision of the SHM refclock in chrony is 1 microsecond, it won't report jitter smaller than that. Add "precision 1e-9" to the SHM line in your chrony.conf to fix that. The configuration files generated by timemaster include that. Ideally chronyd would be using the value from the SHM samples, but some clients didn't set this correctly, so it is currently ignored. -- Miroslav Lichvar ------------------------------------------------------------------------------ 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
