Analysis of 100 Mb/s Ethernet for the Whitney commodity computing testbed

We evaluate the performance of a fast Ethernet network configured with a single switch, a single hub, a combination of hubs and switches, and a 4/spl times/4 2D tents topology in a testbed cluster of "commodity " Pentium Pro PCs. An MPI collective communication benchmark and the NAS Parallel Benchmarks version 2.2 (NPB2) show that the torus network performs best for all sizes that we were able to test (up to 16 nodes). For larger networks the Ethernet switch outperforms the hub, though its performance is far less than peak. The hub/switch combination tests indicate that the NAS parallel benchmarks are relatively insensitive to hub densities of less than 7 nodes per hub.