Design and Performance of Active Messages on the IBM SP-2

Abstract

This technical report describes the design, implementation, and evaluation of Active Messages on the IBM SP-2. The implementation benchmarked here uses the standard TB2 network adapter firmware but does not use any IBM software on the Power2 processor. We assume familiarity with the concepts underlying Active Messages. The main performance characteristics are a one-word message round-trip time of 51.0 $\mu$s and an asymptotic network bandwidth of 34.3 MB/s. After presenting selected implementation details, the paper focuses on detailed performance analysis, including a comparison with IBM's Message Passing Layer (MPL) and Split-C benchmarks.