Each ingress packet to the NIC is accurately timestamped with the following precision parameters:
Device | Accuracy | Precision |
ConnectX-6 Dx | 8 nanoseconds | 4 nanoseconds |
Precision of Rx Timestamp Across Devices
As for the timestamp format: Free-running counter is the default mode.
When the real-time clock is enabled in the hardware, the timestamp format can be UTC/TAI format as well.