A Low-Energy Wide SIMD Architecture with Explicit Datapath

Abstract

Energy efficiency has become one of the most important topics in computing. To meet the ever increasing demands of the mobile market, the next generation of processors will have to deliver a high compute performance at an extremely limited energy budget. Wide single instruction, multiple data (SIMD) architectures provide a promising solution, as they have the potential to achieve high compute performance at a low energy cost. We propose a configurable wide SIMD architecture that utilizes explicit datapath techniques to further optimize energy efficiency without sacrificing computational performance. To demonstrate the efficiency of the proposed architecture, multiple instantiations of the proposed wide SIMD architecture and its automatic bypassing counterpart, as well as a baseline RISC processor, are implemented. Extensive experimental results show that the proposed architecture is efficient and scalable in terms of area, performance, and energy. In a 128-PE SIMD processor, the proposed architecture is able to achieve an average of 206 times speed-up and reduces the total energy dissipation by 48.3 % on average and up to 94 %, compared to a reduced instruction set computing (RISC) processor. Compared to the corresponding SIMD architecture with automatic bypassing, an average of 64 % of all register file accesses is avoided by the 128-PE, explicitly bypassed SIMD. For total energy dissipation, an average of 27.5 %, and maximum of 43.0 %, reduction is achieved.