On Tue, Jul 02, 2019 at 09:36:50AM +0200, Miroslav Lichvar wrote: > On Mon, Jul 01, 2019 at 08:10:43PM -0700, Richard Cochran wrote: > > On Mon, Jul 01, 2019 at 03:53:20PM +0200, Armin HAMAR wrote: > > > Like it's about 300ns for the PPS and -/+10ns for the output of linux PTP > > > the delay is around 938 which looks > > > for me pretty high for a point to point connection? > > > > No it isn't. You need to consider the delays from the MAC through the > > PHY. These can be greater than one microsecond on the i210. > > The igb driver compensates the delays for the I210.
There are some hard coded values in the driver, but the last time I looked, the data sheet indicated a large amount of variability. Also, Intel first had some numbers in the data sheet, and then they were removed. So I suspect that the driver's numbers aren't correct. > So, with two > directly connected I210s (short cable) the measured delay should be > close to zero. That is true of any two devices, since the tx/rx asymmetry cancels out (even without any corrections applied). Thanks, Richard _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
