Centaur: Hybrid Processing in On/Off-chip Memory Architecture for Graph Analytics

The increased use of graph algorithms in diverse fields has highlighted their inefficiencies in current chip-multiprocessor (CMP) architectures, primarily due to their seemingly random-access patterns to off-chip memory. Recently, two families of solutions have been proposed: 1) solutions that offload operations generated by all vertices from the processor cores to off-chip memory; and 2) solutions that offload only operations generated by high-degree vertices to dedicated on-chip memory, while the cores continue to process the work related to the remaining vertices. Neither approach is optimal over the full range of vertex's degrees. Thus, in this work, we propose Centaur, a novel architecture that processes operations on vertex data in on- and off-chip memory. Centaur utilizes a vertex's degree as a proxy to determine whether to process related operations in on- or off-chip memory. Centaur manages to provide up to 4.0× improvement in performance and 3.8× in energy benefits, compared to a baseline CMP, and up to a 2.0× performance boost over state-of-the-art specialized solutions.