220.127.116.11.1. Registers with High Timing Path Endpoint Tension
Timing path endpoints are the nodes (usually registers) that terminate timing paths from a register. The Timing path endpoint is equivalent to the nodes that the get_fanouts command returns, or the overall set of nodes that appear as a "From Node" after running the report_timing command. Register duplication is necessary, but not always sufficient, in helping to distribute the signal more efficiently. In addition, you may need to duplicate or restructure any intermediate logic before duplicating the register.
Tension is the sum over each sink of the distance from the sink to the centroid of all the sinks. The value of tension is therefore dependent on the number of sinks. Register duplication can help to break up these clouds, since they may be the result of the placement solution getting "warped" by the presence of the register.