LightSpMV: Faster CUDA-Compatible Sparse Matrix-Vector Multiplication Using Compressed Sparse Rows

Compressed sparse row (CSR) is one of the most frequently used sparse matrix storage formats. However, the efficiency of existing CUDA-compatible CSR-based sparse matrix vector multiplication (SpMV) implementations is relatively low. We address this issue by presenting LightSpMV, a parallelized CSR-based SpMV implementation programmed in CUDA C++. This algorithm achieves high speed by employing atomic and warp shuffle instructions to implement fine-grained dynamic distribution of matrix rows over vectors/warps as well as efficient vector dot product computation. Moreover, we propose a unified cache hit rate computation approach to consistently investigate the caching behavior for different SpMV kernels, which may have different data deployment in the hierarchical memory space of CUDA-enabled GPUs. We have assessed LightSpMV using a set of sparse matrices and further compared it to the CSR-based SpMV kernels in the top-performing CUSP, ViennaCL and cuSPARSE libraries. Our experimental results demonstrate that LightSpMV is superior to CUSP, ViennaCL and cuSPARSE on the same Kepler-based Tesla K40c GPU, running up to 2.63× and 2.65× faster than CUSP, up to 2.52× and 1.96× faster than ViennaCL, and up to 1.94× and 1.79× faster than cuSPARSE with respect to single and double precision, respectively. In addition, for the acceleration of the PageRank graph application, LightSpMV still keeps consistent superiority to the aforementioned three counterparts. LightSpMV is open-source and publicly available at http://lightspmv.sourceforge.net.