Research On Petri Net Based Dynamic Load Balancing Double-Decked Scheduling Model

Load balancing technology is the effective method of improving the performance and the throughput in distributed system. In this paper, considered the problem of uncertainty, incomplete and instability in the current load balancing algorithm, the problem of single level in the general model of load balancing scheduling, the problem of the advantage of the centralized scheduling strategy ignored by the large-scale system, proposed the dynamic load balancing double-decked model that integrated the easy managed and realization of the centralized scheduling and the expansibility of the distributed scheduling. The model divided distributed system into several relative independent task scheduling groups, each task scheduling group made up by a scheduling server and three workstations, within the group used centralized scheduling, among groups used distributed scheduling, the top subsystem and the bottom subsystem made up by scheduling server and workstations of each task scheduling group respectively.In the process of described the dynamic load balancing double-decked scheduling model, according to the four components of the general load balancing scheduling model, there are net condition of the distributed system, task collection, load indicator and load balancing scheduling strategy, made the description of principle, rule etc., and then modeled the model by the theory of Petri net. The model modeled by the theory of Petri net compared with the model modeled by the common method of model simulation and based on mathematical analysis, which was better reflect the dynamic behavior characteristics of the system, and have more flexibility.Petri net was deemed to be the most powerful tool of research the system performance until now, besides the modeling tool. After accomplished modeling the model, proposed the design program of the system based on the behavior of the model, and finally carry out the performance evaluation by Petri net. When carried out the analysis between the integrated strategies both the centralized scheduling and the distributed scheduling under the dynamic load balancing double-decked scheduling model and many common dynamic load balancing scheduling strategies under the general load balancing scheduling model, the experiment result is the model can decrease the average response time and increase the throughput of the system, thereby, it can improve the performance of the distributed system effectively.