An Asynchronous Protocol for Virtual Factory Simulation on Shared Memory Multiprocessor Systems

The development of parallel simulation technology is seen as an enabler for the implementation of the virtual factory concept, the integrated simulation of all the systems in a factory. One important parallel simulation protocol, the asynchronous deadlock avoidance algorithm proposed by Chandy, Misra, and Bryant, has usually been discussed in the context of distributed memory systems. Also, null messages have normally been associated with this approach for deadlock avoidance. This paper presents a new implementation of the CMB protocol designed for shared memory multiprocessor systems. We have successfully used this protocol, which we call the CMB-SMP protocol, to achieve useful speedups in a manufacturing simulation application, despite the fine granularity of event processing. The implementation eliminates the need for sending null messages, without causing deadlock in the simulation. Double buffering is also used to reduce the overhead of buffer locking. It is shown that the CMB-SMP..

Optimistic synchronization in HLA-based distributed simulation

On behalf of

ABSTRACT INTEROPERATING SIMULATIONS OF AUTOMATIC MATERIAL HANDLING SYSTEMS AND MANUFACTURING PROCESSES

To perform a high fidelity simulation study on a 300 mm wafer fabrication plant, modeling of the manufacturing process (MP) alone is not sufficient. Inclusion of the automated material handling system (AMHS) model is necessary due to the high degree of factory automation. There isn’t, however, a single tool that is capable of modeling both the AMHS and MP with sufficient accuracy and granularity. A commercial simulation package such as AutoMod is usually used to model the AMHS while Auto-Sched AP is usually used to model the MP. These packages can be integrated using the supplied interoperation module but flexibility in optimizing the execution performance for different simulation models is lacking. In this paper, we present an approach to interoperation based on the High Level Architecture standard. We note that the typical characteristic

Implementation Lessons of Performance Prediction Tool for Parallel Conservative Simulation

. Performance prediction is useful in helping parallel programmers answer questions such as speedup scalability. Performance prediction for parallel simulation requires rst working out the performance analyzer algorithms for specic simulation protocols. In order for the prediction results to be close to the results from actual parallel executions, there are further considerations when implementing the analyzer. These include (a) equivalence of code between the sequential program and parallel program, and (b) system eects (e.g. cache miss rates and synchronization overheads in an actual parallel execution). This paper describes our investigations into these issues on a performance analyzer for a conservative, \super-step" (synchronous) simulation protocol. 1 Introduction Parallel programmers often use performance predictions to better understand the behavior of their applications. In this paper, we discuss the main implementation issues to consider in order to obtain accu..

Criticality Of Detailed Modeling In Semiconductor Supply Chain Simulation

Supply chain management offers a large potential for organizations to reduce costs and improve customer service performance. Simulation of supply chains can help in these objectives by evaluating the impact of alternate inventory control policies. Supply chain simulation involves modeling of multiple factories across the chain and can get quite complex. Analysts typically carry out such simulation at a coarse level of detail to keep the complexity and computing resources manageable. However, modeling at coarse levels may reduce the accuracy of outputs and affect the quality of decisions. In this paper, we report on a study to compare the quality of results at different levels of details in a semiconductor supply chain simulation. 1 INTRODUCTION The globalization of markets is forcing the producers to look for ways to improve their competitive positions through focusing on supply chain management. Supply chain management involves planning and managing the flow of material and informatio..

Implementations of Dispatch Rules in Parallel Manufacturing Simulation

Most features in commercial simulation packages are often omitted in parallel simulation benchmarks, because they neither affect the overall correctness of the simulation protocol nor the benchmark's performance. In our work on parallel simulation of a wafer fabrication plant, we however find several features which complicates the implementation of the simulation protocol and affects the program performance. One such feature is the dispatch rules which a machine set uses to decide the priority of the waiting wafer lots. In a sequential simulation, the dispatch rule can be implemented in a straight-forward fashion because the whole system state is at the same simulation time, and the rule simply reads the state variables (of any machine, resources, etc.) In a parallel simulation, the dispatch rule computation may be complicated by the fact that different portions of the simulated system can be at different simulation times. This paper describes our study of the implementation of dispatc..

Implementation Lessons of Performance Prediction Tool for Parallel Conservative Simulation

Performance prediction is a useful thing to do to help parallel programmers answer questions such as speedup scalability. To do performance prediction for parallel simulation, one first has to work out the performance analyzer algorithms for specific simulation protocols. This is only part of the work. In order for the prediction results to be close to what one gets from actual parallel executions, there are further considerations when implementing the analyzer. These include (a) equivalence of code between the sequential program and what might have been in an actual parallel program, and (b) system effects (e.g. cache miss rates and synchronization overheads in an actual parallel execution.) This paper describes our investigations into these issues for a discrete-event simulation program (for wafer fabrication models.) The performance analyzer tries to predict what the speedups will be, if a conservative, "super-step" (synchronous) simulation protocol is used. Because we also have an ..