Bandwidth Compression of Floating-Point Numerical Data Streams for FPGA-Based High-Performance Computing

Abstract

Although computational performance is often limited by insufficient bandwidth to/from an external memory, it is not easy to physically increase off-chip memory bandwidth. In this study, we propose a hardware-based bandwidth compression technique that can be applied to field-programmable gate array-- (FPGA) based high-performance computation with a logically wider effective memory bandwidth. Our proposed hardware approach can boost the performance of FPGA-based stream computations by applying a data compression technique to effectively transfer more data streams. To apply this data compression technique to bandwidth compression via hardware, several requirements must first be satisfied, including an acceptable level of compression performance and a sufficiently small hardware footprint. Our proposed hardware-based bandwidth compressor utilizes an efficient prediction-based data compression algorithm. Moreover, we propose a multichannel serializer and deserializer that enable applications to use multiple channels of computational data with the bandwidth compression. The serializer encodes compressed data blocks of multiple channels into a data stream, which is efficiently written to an external memory. Based on preliminary evaluation, we define an encoding format considering both high compression ratio and small hardware area. As a result, we demonstrate that our area saving bandwidth compressor increases performance of an FPGA-based fluid dynamics simulation by deploying more processing elements to exploit spatial parallelism with the enhanced memory bandwidth.