Optimizing Sparse Matrix Vector Multiplication Using Cache Blocking Method on Fermi GPU

It is an important task to tune performance for sparse matrix vector multiplication (SpMV), but it is also a difficult task because of its irregularity. In this paper, we propose a cache blocking method to improve the performance of SpMV on the emerging GPU architecture. The sparse matrix is partitioned into many sub-blocks, which are stored in CSR format. With the blocking method, the corresponding part of vector x can be reused in the GPU cache, so the time spent on accessing the global memory for vector x is reduced heavily. Experimental results on GeForce GTX 480 show that SpMV kernel with the cache blocking method is 5x faster than the unblocked CSR kernel in the best case.