On Tue, Mar 16, 2021 at 03:52:36PM +0100, Frantisek Rysanek wrote: > On 16 Mar 2021 at 11:25, Miroslav Lichvar wrote: > > > > In the Intel's igc driver I saw few SYNCE registers defined, > > but no code using them. > > > Whoa. igc ? oh there's an i225... didn't know about this one, thanks > for the pointer, this definitely looks promising :-) > Looks like a successor to the i210 generation.
I'm sorry for misleading you. I meant the ice driver (speeds up to 100Gb). I didn't see an out-of-tree version of the igc driver. The I225 might be an interesting NIC for experiments for a different reason. It seems it supports the PCIe Precision Time Measurement (PTM) feature. It is a hardware implementation of an NTP-like protocol over PCIe, which should allow a highly accurate synchronization of the system clock, avoiding the asymmetry on PCIe. It is not supported in the igc driver yet, but there were some patches submitted for it. I measured the PCIe asymmetry with the I210 on few different boards+CPUs and it changed a lot (between about -100ns and 100ns), so I think PTM could make a significant improvement. -- Miroslav Lichvar _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
