Precision Time in the Last Centimeters for Distributed Applications

The accuracy of network time-synchronization has improved to such an extent in recent years that the inaccuracy within the network endpoint often dominates the total end-to-end inaccuracy over the entire path. An advancement in computer architecture, the PCIe Precision Time Measurement (PTM) protocol, together with improved methods of hardware-based timing observation in computer systems have made (and also made verifiable) orders of magnitude of improvement in time accuracy between, for example, a Precision Time Protocol (PTP)-capable Ethernet interface and software running on the computer’s CPU, bringing the time inaccuracy in the last-centimeters from above to far below the inaccuracy typically introduced along the rest of the end-to-end path.