Optimizing I/O performance and application of results on Linear Scaling Methods for Quantum Hall Transport Simulations

This study has focused on an application for Quantum Hall Transport simulations and more specifically on how to overcome an initially identified potential performance bottleneck related to the I/O of wave functions. These operations are required in order to enable and facilitate continuation runs of the code. After following several implementations for performing these I/O operations in parallel (using the MPI I/O library) we showcase that a performance gain in the range 1.5 - 2 can be achieved when switching from the initial POSIX only approach to the parallel MPI I/O approach on both CURIE and HERMIT PRACE Tier-0 systems. Moreover, we showcase that because I/O throughput scales with an increasing number of cores overall the performance of the code is efficient up to at least 8192 processes.