On Network Locality in MPI-Based HPC Applications
Felix Zahn, Holger Fröning · 2020
Data movements through interconnection networks exceed local memory accesses in terms of latency as well as energy by multiple orders of magnitude. While many optimizations make great effort to improve memory accesses, large distances in the network can easily dash these improvements, resulting in increased overall costs. Therefore, a deep understanding of network locality is key for further optimizations, such as improved mapping of ranks to physical entities.