FINGERS: exploiting fine-grained parallelism in graph mining accelerators

Graph mining is an emerging application of high importance and also with high complexity, thus requiring efficient hardware acceleration. Current accelerator designs only utilize coarse-grained parallelism, leaving large room for further optimizations. Our key insight is to fully exploit fine-grained parallelism to overcome the existing issues of hardware underutilization, inefficient resource provision, and limited single-thread performance under imbalanced loads. Targeting pattern-aware graph mining algorithms, we first comprehensively identify and analyze the abundant fine-grained parallelism at the branch, set, and segment levels during search tree exploration and set operations. We then propose a novel graph mining accelerator, FINGERS, which effectively exploits these multiple levels of fine-grained parallelism to achieve significant performance improvements. FINGERS mainly enhances the design of each single processing element with parallel compute units for set operations, and efficient techniques for task scheduling, load balancing, and data aggregation. FINGERS outperforms the state-of-the-art design by 2.8× on average and up to 8.9× with the same chip area. We also demonstrate that different patterns and different graphs exhibit drastically different parallelism opportunities, justifying the necessity of exploiting all levels of fine-grained parallelism in FINGERS.