Optimizing Application Performance on Cray Systems With PGI Compilers and Tools

Overview

PGI Fortran, C and C++ compilers and tools are available on most Cray XT3 and Cray XD1 systems. Optimizing performance of the AMD Opteron processors in these systems often depends on maximizing SSE vectorization, ensuring alignment of vectors, and minimizing the number of cycles the processors are stalled waiting on data from main memory. The PGI compilers support a number of directives and options that allow the programmer to control and guide optimizations including vectorization, parallelization, function inlining, memory prefetching, interprocedural optimization, and others. This paper provides detailed examples of the use of several of these features as a means for extracting maximum single-node performance from Cray systems using PGI compilers and tools.