XTW, a parallel and distributed logic simulator

In this paper, a new event scheduling mechanism XEQ and a new rollback procedure rb-messages are proposed for use in optimistic logic simulation. We incorporate both of these techniques in a simulator XTW. XTW groups LPs into clusters, and makes use of a multi-level queue, XEQ, to schedule events in the cluster. XEQ has an O(1) event scheduling time complexity. Our new rollback mechanism replaces the use of anti-messages by an rb-message, and eliminates the need for an output queue at each LP. Experimental comparisons to Time Warp reveal a superior performance on the part of XTW, while experimental results over large circuits (5-million-gate to 25-million-gate) shows XTW scales well with both the size of circuits and the number of processors.