Cluster queue structure for shared-memory multiprocessor systems

Three basic structures have been proposed to organize the task queues for shared-memory multiprocessor systems: centralized, distributed, and hierarchical. Centralized structures are not suitable for massively parallel systems since the shared queue becomes a bottleneck for frequent enqueuing and dequeuing operations. Distributed structures have load imbalancing problem because of no support for workload sharing between queues. Hierarchical structures intend to combine the advantage of the previous two structures and eliminate their disadvantages. Unfortunately, we find load imbalancing still exists in the hierarchical structure, and has significant impact on system performance, particularly when the workload is heavy and irregular. After identifying the cause of this problem, we propose the use of a clustered structure in place of the hierarchical one. Analyzes and simulations show the proposed structure can provide better load balancing and less contention than the hierarchical one.