Implementing MPI under AP/Linux

A preliminary MPI library has been implemented for the Fujitsu AP1000+ multicomputer running the AP/Linux operating system. Under this environment, parallel programs may be dedicated to a fixed partition, or a number of parallel programs may share a partition. Therefore, the MPI library has been constructed so that messaging operations can be driven by polling and/or interrupt techniques. It has been found that polling works well when a single parallel program is running on a given partition, and that interrupt-driven communication makes far better use of the machine when multiple parallel programs are executing. Gang scheduling of multiple parallel programs which use polling was found to be relatively ineffective.