Auto-vectorizing a large-scale production unstructured-mesh CFD application

For modern x86 based CPUs with increasingly longer vector lengths, achieving good vectorization has become very important for gaining higher performance. Using very explicit SIMD vector programming techniques has been shown to give near optimal performance, however they are difficult to implement for all classes of applications particularly ones with very irregular memory accesses and usually require considerable re-factorisation of the code. Vector intrinsics are also not available for languages such as Fortran which is still heavily used in large production applications. The alternative is to depend on compiler auto-vectorization which usually have been less effective in vectorizing codes with irregular memory access patterns. In this paper we present recent research exploring techniques to gain compiler auto-vectorization for unstructured mesh applications. A key contribution is details on software techniques that achieve auto-vectorisation for a large production grade unstructure...

• Type: Journal
• Year: 2016
• Where: PPOPP
• Authors: Gihan R. Mudalige, I. Z. Reguly, Michael B. Giles
• Keywords: Distributed And Parallel Computing, PPOPP 2016