Raimar Thudt

Cost of state saving & rollback

Approaches to state saving and rollback for a shared memory, optimistically synchronized, simulation executive are presented. An analysis of copy state saving and incremental state saving is made and these two schemes are compared. Two benchmark programs are then described, one a simple, all overhead, model and one a performance model of a regional Canadian public telephone network. The latter is a large SS7 common channel signalling model that represents a very challenging, practical, test application for parallel simulation. Experimental results are presented which show the necessity and sufficiency of incremental state saving for this application.