What does the timestamp value given by the CQE means RoCE Time-Stamping - NVIDIA Docs
is it the time from HCA clock when packet is sent over wire or recived over wire
or its the time CQ is completed,
e.g for RDMA Write with IMM and Signalled,
Sender side CQE TS will be time timestamp when packet is out of wire
and on reciever side CQE TS (since it IMM) is time when packet is recived on wire
is my understanding correct?
Hi @palok ,
Your understanding is correct.
For RoCE timestamping, the CQE timestamp is sampled from the HCA’s internal clock:
Send side: The timestamp is taken when the packet is sent to the wire (leaves the NIC port)
Receive side: The timestamp is taken when the packet is received from the wire (arrives at the NIC port)
Regards,
Chen