Profiling of Code_Saturne with HPCToolkit and TAU, and autotuning Kernels with Orio

This study has profiled the application Code Saturne, which is part of the PRACE benchmark suite. The profiling has been carried out with the tools HPCtookit and Tuning and Analysis Utilities (TAU) with the target of finding compute kernels suitable for autotuning. Autotuning is regarded as a necessary step in achieving sustainable performance at an Exascale level as Exascale systems most likely will have a heterogeneous runtime environment. A heterogeneous runtime environment imposes a parameter space for the applications run time behavior which cannot be explored by a traditional compiler. Neither can the run time behavior be explored manually by the developer/code owner as this will be too time consuming. The tool Orio has been used for autotuning idenitified compute kernels. Orio has been used on traditional Intel processors, Intel Xeon Phi and NVIDIA GPUs.The compute kernels have a small contribution to the overall execution time for Code Saturne. By autotuning with Orio these kernels have been improved by 3-5%..