A load balancing mechanism for large scale multiprocessor systems and its implementation

In large scale multiprocessor systems, the distance between processors should be taken into account by software to reduce the network traffic and the communication overhead. A load balancing method based on P³ (Processing Power Plane) model is proposed to enable programmers to specify distributing computational load, keeping the locality of the computation. In this method, a process is allocated to a rectangle on a hypothetical processing power plane. The size of the rectangle represents the processing power given to the process, and the distance between rectangles represents the communication cost between them. This plane is divided to processors, and the region of the processor may be dynamically reshaped to alleviate imbalance on P³. Mechanism for realization of the method has been implemented on the Multi-PSI/version, 2, which is a parallel processing system with 64 processing elements connected to form a 2-dimensional mesh network. A packet transmission mechanism of the Multi-PSI/version 2 is described, which realizes the process distribution along with the balancing method.