SparSynergy: Unlocking Flexible and Efficient DNN Acceleration Through Multi-Level Sparsity

To more effectively address the computational and memory requirements of deep neural networks (DNNs), leveraging multi-level sparsity-including value-level and bit-level sparsity-has emerged as a pivotal strategy. While substantial research has been dedicated to exploring value-level and bit-level sparsity individually, the combination of both has largely been overlooked until now. In this paper, we propose SparSynergy, which-to the best of our knowledge-is the first accelerator that synergistically integrates multi-level sparsity into a unified framework, maximizing computational efficiency and minimizing memory usage. However, jointly considering multi-level sparsity is non-trivial, as it presents several challenges: (1) increased hardware overhead due to the complexity of incorporating multiple sparsity levels, (2) bandwidth-intensive data transmission during multiplexing, and (3) decreased throughput and scalability caused by bottlenecks in bit-serial computation. Our proposed SparSynergy addresses these challenges by introducing a unified sparsity format and a cooptimized hardware design. Experimental results demonstrate that SparSynergy achieves a 5.38 x geometric mean improvement in the energy-delay product (EDP) when compared with the tensor core, across workloads with varying degrees of sparsity. Furthermore, SparSynergy significantly improves accuracy retention compared to state-of-the-art accelerators for representative DNNs.