ComPaSS: efficient communication services for scalable architectures

The authors describe the initial implementation of the ComPaSS communication library to support scalable software development in massively parallel processors. ComPaSS provides high-level global communication operations for both data manipulation and process control, many of which are based on a small set of low-level communication primitives. The ComPaSS library is unique in that these low-level operations are provably optimal for a class of architectures representative of many commercial scalable systems-in particular, those using wormhole routing and n-dimensional mesh network topologies. The authors concentrate on the multicast component of the ComPaSS library, which is useful in several data parallel operations. The design of the multicast primitive is described, and an example of its use in a data parallel application is given. Improvements in performance resulting from use of the library on a 64-node nCUBE-2 are presented