For accurate PTP synchronization, make sure to disable Ethernet flow control.
ethtool -A <iface> rx off tx off
This configuration is not persistent, i.e., it is lost on network adapter port resets, reboots as well as firmware upgrades.
By default, coarse TX timestamps are supplied for all outgoing packets. The accuracy of these timestamps is affected when the NIC is put under load (when other traffic is being transmitted). To obtain high-quality TX timestamps for select packets (e.g., PTP packets), apply the following configuration:
ethtool --set-priv-flags <ifs-name> tx_port_ts on
To disable this feature, enter:
ethtool --set-priv-flags <ifs-name> tx_port_ts off
This configuration is not persistent, i.e. it is lost on network adapter port resets, reboots as well as firmware upgrades.
Minimum firmware version: xx.29.1016
Minimum MLNX_OFED version: 5.4-1.0.3.0