Adaptive Parallelism and Piranha

. Under "adaptive parallelism," the set of processors executing a parallel program may grow or shrink as the program runs. Potential gains include the capacity to run a parallel program on the idle workstations in a conventional LAN---processors join the computation when they become idle, and withdraw when their owners need them---and to manage the nodes of a dedicated multiprocessor efficiency. Experience to date with our Piranha system for adaptive parallelism suggests that these possibilities can be achieved in practice on real applications at comparatively modest costs. Keywords: Parallelism, networks, multiprocessors, adaptive parallelism, programming techniques, Linda, Piranha. 1 Introduction Most work on parallelism is "static": it assumes that programs are distributed over processor sets that remain fixed throughout the computation. If a program starts out on 64 processors, it runs on exactly 64 until completion, and specifically on the same 64. "Adaptive parallelism" (AP) abo..