GROMACS version: 2020.2
GROMACS modification: No
MPI Library: OpenMPI 4.0.5
Job input: ion_channel.tpr from Unified European Applications Benchmark Suite
I’ve been running some performance tests on AWS public cloud using EC2 instances (c5.4xlarge) in a private VPC and cluster placement group. I’ve noticed the performance scaling is really odd with two nodes performing just 20-30% better than a single node and similar with performance across 4 and 8 nodes. I’ve noticed the same trend with a smaller job input.
I have also tried using larger instances with better networking (i.e. elastic fabric adapter) and noticed the same.
Has anybody else noticed the same or is this an inherent feature of running HPC in the cloud?