Title

The Pessimism behind Optimistic Simulation

Authors

George Varghese, Washington University in St Louis
Roger D. Chamberlain, Washington University in St LouisFollow
William E. Weihl, Washington University in St Louis

Document Type

Technical Report

Publication Date

1993

Filename

WUCS-93-54.pdf

DOI:

10.7936/K73J3B90

Technical Report Number

WUCS-93-54

Abstract

In this paper we make an analogy between the time that storage must be maintained in an optimistic simulation and the blocking time in a conservative simulation. By exploring this analogy, we design two new Global Virtual Time (GVT) protocols for Time Warp systems. The first simple protocol is based on the null message scheme proposed for clock advancement in some conservative approaches; this yields what we call Local Guaranteed Time. Our main contribution is a second new protocol that is inspired by Misra's circulating marker scheme for deadlock recovery in conservative simulations, and appears to have advantages over previous GVT algorithms. It is simple enough to be implemented in hardware, takes no overhead in the normal path, can be made to work over non-FIFO links, and its overhead can be dynamically tuned based on computational load.

Comments

Permanent URL: http://dx.doi.org/10.7936/K73J3B90

Recommended Citation

Varghese, George; Chamberlain, Roger D.; and Weihl, William E., "The Pessimism behind Optimistic Simulation" Report Number: WUCS-93-54 (1993). All Computer Science and Engineering Research.
https://openscholarship.wustl.edu/cse_research/549