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Many people ignore various actual or equivalent expenses in running on AWS (like optimization opportunities or bad scaling). It's old, but NASA did a study [1]
by gnufx 3y ago
Many people ignore various actual or equivalent expenses in running on AWS (like optimization opportunities or bad scaling). It's old, but NASA did a study [1] that rings true and I didn't see rebutted. I saw it after an AWS HPC expert stated that you could scale tightly-coupled MPI applications like density functional theory (think 3D FFTs) on EC2; I eventually got him to admit that was rubbish -- and not the only rubbish claim. The "low latency" network is at least no better than I measured intra-switch with the normal 1GbE NICs on Sun x2200s long ago -- an order of magnitude worse than real HPC fabrics.
1. https://www.nas.nasa.gov/assets/nas/pdf/papers/NAS_Technical_Report_NAS-2018-01.pdf https://www.nas.nasa.gov/assets/nas/pdf/papers/NAS_Technical...
- dekhn 3y agoAre you familiar with UltraCluster? https://aws.amazon.com/ec2/ultraclusters/ https://aws.amazon.com/ec2/ultraclusters/ It's a product directly intended to compete with other HPC fabrics. I believe it was launched after your paper was published. Even before then, AWS had ways of placing all your jobs on the same rack, which used same-rack switching. Whenever AWS told us stuff about HPC we tested it carefully, and I'd say that before ultracluster, AWS was being misleading about performance, although Azure was not.
- gnufx 3y agoI don't do AWS any more, but the adapters apparently used with UltraCluster had a latency of 15µs last I knew. I think the NAS benchmarks are overall less latency sensitive than DFT and would benefit less from GPUs, and I assume UltraCluster is rather expensive even by AWS standards.