Application Experiments: MPPA and FPGA

This paper describes the mapping approach, programmability, and performance of the Ambric massively parallel processor array (MPPA), and compares these aspects to an FPGA. Two application kernels, a trellis decoder, and n-gram frequency counter, were ported to the Ambric development system and an Altera Stratix II. We find that the mapping strategies to Ambric and FPGAs are similar at the high level, but diverge quite a bit in implementation due to differences in granularity between the basic compute units of the two devices. Both require substantial refactoring from the baseline sequential algorithm. The FPGA proved superior in terms of performance, but the Ambric fares significantly better than the FPGA in programmability and ease of application development.