Computing global virtual time in shared-memory multiprocessors

Abstract

Global virtual time (GVT) is used in the time-warp synchronization mechanism to perform irrevocable operations and to reclaim storage. GVT computation is much simpler in shared-memory multiprocessors than in message-passing systems because they normally guarantee that no two processors will observe a set of memory operations as occurring in different orders. Exploiting this fact, an efficient, asynchronous, shared-memory GVT algorithm is proposed and its correctness is proven. A new mechanism called on-the-fly fossil collection which enables efficient storage reclamation for simulations containing large numbers is also proposed. It can be used in time-warp systems executing on shared-memory or message-based machines.