CAB: Cache Aware Bi-tier Task-Stealing in Multi-socket Multi-core Architecture

Modern multi-core computers often adopt a multi-socket multi-core architecture with shared caches in each socket. However, traditional task-stealing schedulers tend to pollute the shared cache and incur more cache misses due to their random stealing. To relieve this problem, this paper proposes a Cache Aware Bi-tier (CAB) task-stealing scheduler, which improves the performance of memory-bound applications by reducing memory footprint and cache misses of tasks running inside the same CPU socket. CAB uses an automatic partitioning method to divide an execution Directed Acyclic Graph (DAG) into the inter-socket tier and the intra-socket tier. Tasks generated in the inter-socket tier are scheduled across sockets, while tasks generated in the intra-socket tier are scheduled within the same socket. Experimental results show that CAB can improve the performance of memory-bound applications up to 68.7% compared with the traditional task-stealing.