On Mon, Nov 13, 2017 at 01:54:32PM +0100, Frantisek Rysanek wrote: > I have the privilege to play around with your software, on a > Skylake-based platform containing an Intel i219LM > (alongside i210 which seems to give comparably mediocre results). > > I also have the privilege to test your software against a > latest-generation Meinberg GrandMaster (HPS100). > > I first tried your software on the stock kernel in Debian 8 > (3.16.something if memory serves) - and the "timed out while ..." > errors prompted me to upgrade to the latest vanilla, which happens to > be 4.13.12 at the time of this writing. > The errors are now less frequent, but they do occur.
Okay, so maybe the remaining errors are due to latency within your system. The default tx_timestamp_timeout is 1 millisecond. Try 10 and see if that fixes the problem. > Notice how the errors become more frequent after 9 a.m. > - I came to the machine and started a PCAP sniffer > on that same port. That fact supports the idea that the cause is latency. > The one thing that has stunned me in a nice way: > I first ran ptp4l against the GM through two managed switches, > not very loaded, but unaware of PTP. > That resulted in the "offset" jumping within +/- 700 "units". > After I got the idea to plug the client straight into the GM, > the "offset" now wanders within +/- 10 "units". Yes, that is the expected performance. Store and forward switches do introduce such errors. > That's an improvement of two decimal orders :-D > Wonderful :-) > What are those units BTW? PPB? Nanoseconds? Nanoseconds. Thanks, Richard ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
