Time warp for efficient parallel logic simulation on a massively parallel SIMD machine

Abstract

A variation of the time warp protocol for efficient parallel logic simulation on a massively parallel SIMD machine is proposed. A scheme in which each object has a single event queue instead of three queues needed in the conventional time warp protocol is developed for fast queue manipulation and small storage requirement. An immediate cancellation technique of the rollback mechanism of time warp is proposed which does not require the use of antimessages and works well for the single queue structure. To minimize the queue size needed for simulation, a lower bound of rollback at each object is computed and used to discard processed events with timestamps less than the bound. Even if extra work is needed for computing and delivering the lower bound, the simulation using the lower bound of rollback is faster than the time warp protocol since queue manipulation time is significantly saved. Preliminary experimental results of the time warp variation on the Connection Machine-2 indicate significant savings in time and space over the time warp protocol. Moreover, the proposed scheme is much faster than the Intermetric VHDL simulator. >