MPI for the Clint Gb/s Interconnect

The Clint network provides an FPGA-based segregated architecture with a bulk channel controlled by a quick channel. We report in this paper how, in order to implement efficiently the MPI APIs on top of this network, we “codesigned” the interface between the SunTM MPI communication stack and the network FPGAs. The SunTM MPI “Protocol Module” we developed implements functions to enable a full support of Sun MPI and gave us an insightful view of the design problems and performance bottlenecks. Hence, we were able to provide pertinent feedback to the hardware designers who then, thanks to the use of rapid FPGA-prototyping, implemented the corresponding hardware enhancements. As a result, our software architecture fits as much as possible with the hardware capabilities and the resulting prototype exploits the best of the overall architecture.