MIGRANT THREADS ON PROCESS FARMS: PARALLEL PROGRAMMING WITH ARIADNE'"

We present a novel and portable threads-based system for the development of concurrent applications on shared and distributed memory environments. Implementing user-space threads. the Ariadne system is highly effective for medium to coarse grained applications. Sequential programs are readily converted into parallel programs for shared ordistributed memory, with low development effort. We describe basic threads primitives, and constructs for synchronization and computation in concurrent applications. Ariadne flexibly caters to a variety of communication environments, through a simple interface. It supports the development ofcustomized schedulers on shared memory mulliprocessors, and offers a thread migration capability for distributed environments. Scheduling ofcomputations at the thread level offers both task- and data-driven executions. Thread migration is a powerful feature which turns remote memory accesses into local accesses, enables load-balancing and simplifies program development. Ariadne currently runs on the SPARe (SunGS 4.x, SunGS 5.x), Sequent Symmetry, Intel Paragon, Silicon Graphics IRIX, and ffiM RS/6000 environments. We present Ariadne's parallel programming capability through several examples, reporting on performance measurements obtained with each