> We didn't have HPC workloads, just Postgres, which uses one OS process per connection, and performance was terrible as a result.
I'd bet, but not too much, that that was more due to a) postgres' internal locking implementation scaling horribly at that time b) zone_reclaim_mode leading to bad behaviour around IO.
It's possible, but we weren't testing 48 clients at that time, just our normal workload, which had much less parallelism than that. The person in charge of setting up the systems explained the performance issues as being due to NUMA.
I'd bet, but not too much, that that was more due to a) postgres' internal locking implementation scaling horribly at that time b) zone_reclaim_mode leading to bad behaviour around IO.