Low Overhead Message Passing for High Performance Many-Core Processors

Many-core processors provide the raw computation power required by modern high-performance multimedia and signal processing workloads. The translation of this into execution performance is often constrained by the overheads of communication between concurrent tasks. This paper presents Pronto, a low overhead message passing system which simplifies the semantics of data movement between communicating tasks by performing buffer management, message synchronization and address translation directly in hardware. The integration of these functions into hardware results in transfer latencies up to 30% shorter than state of the art MPI derivatives. The overheads for communication in a 16-core processor array are under 5% for 64-word burst transfers with Pronto using workloads such as the JPEG decoder and FIR filter. Furthermore, this paper also studies the effect of task mapping and interconnect traffic on the predictability of data block arrival times, and illustrates a method to reduce variations.