SIGSIM

In Time Warp parallel simulation, the state of each process must be saved (checkpointed) regularly in case a rollback is necessary. Although most existing Time Warp implementations checkpoint after every state transition, this is not necessary, and the ...

We have previously shown that the mathematical technique of uniformization can serve as the basis of synchronization for the parallel simulation of continuous-time Markov chains. This paper reviews the basic method and compares four different methods ...

Time-parallel simulations exploit parallelism by partitioning the time domain of a simulation model. Exploiting temporal parallelism requires predicting future states of a simulation model. A poor prediction of future states may cause extensive ...

A number of optimistic synchronization schemes for parallel simulation rely upon a global synchronization. The problem is to determine when every processor has completed all its work, and there are no messages in transit in the system that will cause ...

Global virtual time (GVT) is used in distributed simulations to reclaim memory, commit output, detect termination, and handle errors. It is a global function that is computed many times during the course of a simulation. A small GVT latency (delay ...

The major goal of this work has been to develop an implementation of a parallel partitioning algorithm which is suitable for use in a conservatively synchronized Parallel Discrete Event Simulation (PDES) environment. Effective partitioning is essential ...

A hardware-based framework which supports a wide range of parallel discrete event synchronization protocols has been proposed in [Reyn92]. This framework offloads all synchronization activity from the host processors and host communication network in ...

Several mathematical and algorithmic problems that have arisen in discrete event simulations of large systems are described. The simulated systems belong to the areas of computational physics, queueing networks, and econometric models.

Although users may want to employ shared variables when they program distributed simulation applications, almost none of the currently existing distributed simulation systems do offer this facility. In this paper, we present new algorithms which provide ...

An approach for high performance parallel logic simulation on a local area network of workstation computers is discussed in this paper. The single, shared transmission medium often found in such networks places limitations on parallel execution, hence a ...

Time Warp has evolved to a common technique for distributed simulation. Speedup in Time Warp simulation systems mainly depends on two overhead factors: first, the load on the simulators has to be well balanced and second, communication and rollbacks ...

In this paper we consider the effect of using bus interconnection structures on the overheads present in conservative parallel simulations of multicomputer programs. We use a modified version of the Poker Programming Environment to empirically measure ...

The implementation of the pending event set (PES) is crucial to the execution speed of discrete event simulation programs. This paper studies the implementation of the PES in the context of simulations executing on parallel computers using the Time Warp ...

Time Warp and Breathing Time Buckets are two general-purpose optimistic synchronization strategies for supporting parallel discrete-event simulations. However, each one of these approaches has potential fatal shortcomings. Time Warp may exhibit rollback ...

The two main approaches to parallel discrete event simulation – conservative and optimistic – are likely to encounter some limitations when the size and complexity of the simulation system increases. For such large scale simulations, the conservative ...

The successful application of optimistic synchronization techniques in parallel simulation requires that rollback overheads be contained. The chief contributions to rollback overhead in a Time Warp simulation are the time required to save state ...

This work presents results from an experimental evaluation of the space-time tradeoffs in Time Warp augmented with the cancelback protocol for memory management. An implementation of the cancelback protocol on Time Warp is described that executes on a ...

We describe, in this paper, a synchronization/deadlock resolution mechanism for a network of communicating finite state machines implemented on a parallel machine. As it is message-based, it is appropriate for distributed memory machines.

The technique ...

Recent experiments have shown that conservative methods can achieve good performance by exploiting the characteristics of the system being simulated. In this paper we focus on the interrelationship between run time and synchronization requirements of a ...

Optimistic methods of synchronizing parallel discrete event simulations can be risky by sending (positive) messages (events) before they have been committed. Risky methods often use anti-messages (negative messages) to cancel incorrectly sent positive ...

Synchronization is a significant cost in many parallel programs, and can be a major bottleneck if it is handled in a centralized fashion using traditional shared-memory constructs such as barriers. In a parallel time-stepped simulation, the use of ...

The suitability of the Time Warp mechanism to perform simulations with real-time constraints is examined. A model for Time Warp is developed that accounts for overheads such as state saving, state restoration, and sending and transmitting positive and ...