TDGraph

Many solutions have been recently proposed to support the processing of streaming graphs. However, for the processing of each graph snapshot of a streaming graph, the new states of the vertices affected by the graph updates are propagated irregularly along the graph topology. Despite the years' research efforts, existing approaches still suffer from the serious problems of redundant computation overhead and irregular memory access, which severely underutilizes a many-core processor. To address these issues, this paper proposes a topology-driven programmable accelerator TDGraph, which is the first accelerator to augment the many-core processors to achieve high performance processing of streaming graphs. Specifically, we propose an efficient topology-driven incremental execution approach into the accelerator design for more regular state propagation and better data locality. TDGraph takes the vertices affected by graph updates as the roots to prefetch other vertices along the graph topology and synchronizes the incremental computations of them on the fly. In this way, most state propagations originated from multiple vertices affected by different graph updates can be conducted together along the graph topology, which help reduce the redundant computations and data access cost. Besides, through the efficient coalescing of the accesses to vertex states, TDGraph further improves the utilization of the cache and memory bandwidth. We have evaluated TDGraph on a simulated 64-core processor. The results show that, the state-of-the-art software system achieves the speedup of 7.1~21.4 times after integrating with TDGraph, while incurring only 0.73% area cost. Compared with four cutting-edge accelerators, i.e., HATS, Minnow, PHI, and DepGraph, TDGraph gains the speedups of 4.6~12.7, 3.2~8.6, 3.8~9.7, and 2.3~6.1 times, respectively.