Optimizing MPI Performance (Real Examples)

MPI jobs that run are easy. MPI jobs that run fast and efficiently — that’s where things get interesting. If your application scales poorly, takes longer than expected, or wastes CPU time, the issue is usually not the code itself… it’s how it’s running. That said, performance tuning is rarely about a single fix. The examples below highlight common issues and improvements, but in real-world HPC workloads, these are often just one of several factors impacting performance. Here’s a practical breakd