The final list of changes is supposed to be with the internal version, and roughly seem to show a 20% change over and above what the basic std::map -> ext/hash_

The final list of changes is supposed to be with the internal version, and roughly seem to show a 20% change over and above what the basic std::map -> ext/hash_map replacement. I'm not sure if I should add the percentages, or multiply them along to get the final runtime, though that doesn't make much difference, really :) You're right that there may not be much improvement, but I've seen the google dense_hash_map do better sometimes than the basic SGI hash_map. Edit: the code repo has the unoptimized versions. Oh well, at least I can get the satisfaction of seeing the 30% myself :)