Performance of the Cray T3D and Emerging Architectures on Canopy QCD Applications

Abstract

The Cray T3D, an MIMD system with NUMA shared memory capabilities and in principle very low communications latency, can support the Canopy framework for grid-oriented applications. CANOPY has been ported to the T3D, with the intent of making it available to a spectrum of users. The performance of the T3D running Canopy has been benchmarked on five QCD applications extensively run on ACPMAPS at Fermilab, requiring a variety of data access patterns. The net performance and scaling behavior reveals an efficiency relative to peak Gflops almost identical to that achieved on ACPMAPS. Detailed studies of the major factors impacting performance are presented. Generalizations applying this analysis to the newly emerging crop of commercial systems reveal where their limitations will lie. On these applications, efficiencies of above 25\% are not to be expected; eliminating overheads due to Canopy will improve matters, but by less than a factor of two.