1. A method comprising: defining, by a computing system, coverage for system level functionality of a circuit design as a set of system level coverage points, each corresponding to a different portion of system level functionality of the circuit design; correlating, by the computing system, the system level coverage points in the set according to characteristics of the different portions of the system level functionality corresponding to the system level coverage points; and utilizing, by the computing system, the correlated set of system level coverage points to identify system level functionality left uncovered by events performed by the circuit design during simulation with one or more regressions.