Concord: re-thinking the division of labor in a distributed shared memory system

A distributed shared memory system provides the abstraction of a shared address space on either a network of workstations or a distributed-memory multiprocessor. Although a distributed shared memory system can improve performance by relating the memory consistency model and maintaining memory coherence at a granularity specified by the programmer, the challenge is to offer ease of programming while maintaining high performance. Concord meets this challenge by carefully splitting responsibilities among the programmer, the compiler, and the runtime system. Concord has allowed a single programmer to port several real, large shared-memory parallel programs onto an Intel iPS/2 in a few weeks and achieve reasonable speedup.<>