Intel® MPI Benchmarks User Guide and Methodology Description

# Warm-Up Phase (IMB-MPI1, IMB-EXT, IMB-NBC, and IMB-RMA)

Before starting the actual benchmark measurement for `IMB-MPI1`, `IMB-EXT`, `IMB-NBC`, and `IMB-RMA`, the selected benchmark is executed `N_WARMUP` times with a `sizeof(assign_type)` message length. The `N_WARMUP` value is defined in `IMB_settings.h`, see Parameters Controlling Intel® MPI Benchmarks for details. The warm-up phase eliminates the initialization overhead from the benchmark measurement.