(Didn't find this on LtU yet, apologies if it is a dupe.) While all benchmarks are questionable, I found this 3 way comparison for a given concurrency situation to be of interest.

This is a continuation of Parallel Ant Colony Optimization for TSP in Standard ML and Multi-Core Ant Colony Optimization for TSP in Haskell. Here the program has been rewritten in the programming language Erlang.