Hybrid-SIMD: A Modular and Reconfigurable Approach to Beyond von Neumann Computing

The increasing complexity of real-life applications demands constant improvements of microprocessor systems. One of the most frequently adopted microprocessor design scheme is the von Neumann architecture. Central Processing Unit (CPU) performs computations and communicates with memory in a constant exchange of information. This unceasing motion of data between these two components became a significant performance bottleneck. A lot of power, energy, and computational time are wasted in this communication. With Beyond von Neumann Computing (BvNC) paradigms, calculations are performed inside or very close to a memory array. BvNC approaches are proposed in the literature, mainly based on modifications of existing memories, enabling simple computations. Others exploit emerging technologies to both store and compute data, using analog operations. In this work we follow a different approach, where computational units are placed close to memory cells, improving versatility and performance. We propose a Hybrid-SIMD architecture made of memory and computing elements in an interleaved structure. Hybrid-SIMD can be used both as a low density memory and as SIMD accelerator. We insert our design in a classical von Neumann system based on a RISC-V processor, and we estimate its impact, demonstrating its capability to improve speed reducing at the same time energy consumption.