Lookahead Accumulation in Conservative Parallel Discrete Event Simulation

Lookahead is a key issue in distributed discrete event simulation. It becomes explicit in conservative simulation algorithms, where the two major approaches are the asynchronous null-message (CMB) algorithms and the synchronous window algorithms (CTW). In this paper we demonstrate how a hybrid algorithm can maximize the lookahead capabilities of a model by lookahead accumulation. Furthermore, per processor aggregation of the logical processes allows for tuning of the granularity. A qualitative performance analysis shows that in case of no hop-models our algorithm outperforms the traditional conservative algorithms. This is due to reduced synchronisation overhead caused by longer independent computation cycles, generated by the lookahead accumulation across the shortest lookahead path.