1. A method of simulation processing in a data processing system, said method comprising: at a simulation client, simulating a design utilizing a hardware description language (HDL) simulation model by stimulating the HDL simulation model with a testcase, wherein the HDL simulation model includes instrumentation not forming a portion of the design that includes a plurality of count event counters that count occurrences of count events in the design during stimulation by the testcase; at multiple intervals during stimulation of the HDL simulation model by the testcase, the simulation client recording count values of the plurality of count event counters; the simulation client determining, for each of the multiple intervals, a temporal statistic regarding the count values of the plurality of count event counters; and the simulation client outputting a report containing temporal statistics for the multiple intervals.