Comment by jeffbee

A more recent benchmark is https://martin.ankerl.com/2022/08/27/hashmap-bench-01/

However, it lacks the newer Boost stuff which is very fast.

The Hopscotch map was interesting at the time but due to unfortunate timing was immediately outshone by absl::unordered_flat_map A.K.A. "Swiss tables", and there's been even more water under the bridge since then.