Parallel Scan on Ascend AI Accelerators
Bartłomiej Wróblewski, Gioele Gottardo, Anastasios Zouzias · 2025
We design and implement parallel prefix sum (scan) algorithms using Ascend AI accelerators. Ascend accelerators feature specialized computing units—the cube units for efficient matrix multiplication and the vector units for optimized vector operations. A key feature of the proposed scan algorithms is their extensive use of matrix multiplications and accumulations enabled by the cube unit.We present a multi-core scan algorithm that fully utilizes both the cube and vector units of Ascend, reaching up to 37.5% of the theoretical memory bandwidth. In addition, our radix sort implementation, which utilizes matrix multiplications for its parallel splits, highlights the potential of matrix engines in enhancing complex operations (3.3× speedup over the vector-only baseline).