On the scalability and dynamic load balancing of parallel Verilog simulations

As a consequence of Moore's law, the size of integrated circuits has grown extensively, resulting in simulation becoming the major bottleneck in the circuit design process. In this paper, we examine the performance of a parallel Verilog simulator on large, real designs. As previous work has made use of either relatively small benchmarks or synthetic circuits, the use of these circuits is far more realistic. We develop a parser for Verilog files enabling us to simulate in parallel all synthesizable Verilog circuits. We utilize four circuits as our test benches; the LEON Processor, the OpenSparc T2 processor and two Viterbi decoder circuits. We observed 4,000,000 events per second on 32 processors for the Viterbi decoder with 800k gates. A dynamic load balancing approach is also developed which uses a combination of centralized and distributed control in order to accommodate its use for large circuits.