A DISTRIBUTED FAIR POLLING SCHEME APPLIED TO OR-PARALLEL LOGIC PROGRAMMING

A task scheduling algorithm for parallel execution of logic programs on NUMA multiprocessors is proposed. The algorithm endorces a so-called fair polling policy. We show analytically that the proposed algorithm has a good iso-efficiency function. Results from simulation on switch based NUMA architecture multiprocessors, the BBN Butterfly GP1000 and TC2000, corroborate the analysis. The proposed algorithm exhibits performance characteristics very similar to that of its counterpart that uses a shared memory. It achieves reasonable speed-up on benchmarks, using a nonconstant time task migration protocol. In addition, fair polling algorithms (with or without a shared memory) are shown to be consistently superior than several other known polling schemes that do not maintain fairness, for a variety of benchmark programs.