I/O-profiling with Darshan

Darshan is a set of libraries that can characterize MPI-IO and POSIX file access within typical HPC applications in a nonintrusive way. It can be used to investigate I/O behavior of a MPI-program. An application’s I/O behavior can easily be an obstacle to achieving petascale performance. Hence, to be able to characterize the I/O of a HPC-application is an important step on the path to develop scaling properties. Darshan have been used on selected applications from task 7.1 and 7.2. This whitepaper describes the work carried out and the results achieved