MULTES: Multilevel Temporal-Parallel Event-Driven Simulation

Multilevel temporal-parallel event-driven simulation is a new radically different approach to simulation of designs described in Verilog HDL. It is based on a concept of time-parallel simulation applied to gate-level timing simulation. The simulation is performed in two steps: 1) fast reference simulation that runs on a higher, reference-level design model (typically RTL) and saves the design state at predetermined checkpoints; and 2) target simulation, which runs on a lower, gate-level model and distributes the simulation run slices to individual simulators. The paper addresses a number of important issues that make this approach practical: 1) finding initial state for each simulation slice; 2) resolving initial state mismatches; and 3) handling designs with multiple asynchronous clocks. Experimental results performed on industrial designs demonstrate the validity and efficiency of the method in terms of its performance and the debugging efficiency.