LogP Performance Assessment of Fast Network Interfaces David E. Culler Computer Science Division University of California, Berkeley In recent years, we have seen dramatic advances in scalable, low-latency interconnection networks for parallel machines and workstation clusters. With such "hot interconnects," the performance of user-to-user communication is limited primarily by the network interface, rather than the switches and links. We present a systematic performance assessment of the hardware and software that provides the interface between applications and emerging high-speed networks. Using LogP as a conceptual framework and Active Messages as the communication layer, we devise a set of communication microbenchmarks. These generate a graphical signature from which we extract the LogP performance parameters of latency, overhead, and bandwidth. The method is illustrated on three diverse platforms: Intel Paragon, Meiko CS-2, and a cluster of SparcStations with Myrinet. The study provides a detailed breakdown of the differences in communication performance among the platforms. While the details of our microbenchmark depend on Active Messages, the methodology can be applied to conventional communication layers.