> -----Original Message----- > From: Richard Cochran [mailto:richardcoch...@gmail.com] > Sent: Monday, May 20, 2019 9:11 AM > To: Miroslav Lichvar <mlich...@redhat.com> > Cc: Sanjay Bhandari <san...@ziffusion.com>; > linuxptp-users@lists.sourceforge.net; > Keller, Jacob E <jacob.e.kel...@intel.com> > Subject: Re: [Linuxptp-users] Is the PPS timestamp system time or PHC time? > > On Mon, May 20, 2019 at 05:10:26PM +0200, Miroslav Lichvar wrote: > > error, except the nanosecond resolution. The NICs supported by the > > e1000e driver using ART for cross timestamping seem to be better than > > 1 microsecond and are possibly much better than that, but there > > doesn't seem to be any documentation that would explain how exactly it > > works and what would be the maximum error. > > With cross timestamping and ART, you are using hardware time stamping, > so I would expect the error to be under 100 nanoseconds (or so). > > @Jake, any insights on this point? >
Hm. I don't have the numbers for that offhand, but I would absolutely expect something close to that, since we're having the hardware perform the timestamps as close as possible together. I have a few people I can ask if they know the timing characteristics for cross timestamping. Regards, Jake > Thanks, > Richard _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
