Optimistic protocols designed for Parallel Discrete Event Simulation
(PDES) rely heavily on the Global Virtual Time (GVT)
calculation. Since the simulation uses large amounts of memory, the
GVT is used to synchronize processes and discard obsolete system
information. In this paper we present a new algorithm, the
Continuously Monitored Global Virtual Time (CMGVT). Unlike others,
this algorithm allows processes to calculate the GVT based on the
local information currently available to each process. System
information, such as the Local Virtual Time (LVT) of each process and
information about messages in transit, is appended to simulation
messages. We present experimental data that show the performance of
the algorithm.