Onload supports hardware timestamping of UDP and TCP packets received over a supported interface. A timestamp is generated when the first byte enters the adapter.
Setting the SO_TIMESTAMPING option using
setsockopt() enables hardware timestamping on TCP or
UDP sockets. Timestamps are generated by the adapter for each received packet. Timestamp
resolution is <8ns on an X2 series adapter.
Functions such as cmesg(), recvmsg() and recvmmsg() can
then recover hardware timestamps for packets recovered from a socket.
The Onload stack for the socket must have the environment variable EF_RX_TIMESTAMPING set. See Parameter Reference for details.