Does anyone have other ideas on how to tune the Lua interpreter to squeeze more performance?
My experience with Visual Studio (on windows) is that rebuilding the sources using profile guided optimization can almost double my program speeds. Not sure if it would translate to Linux -- but, insomuch as you do have the capacity to do a build that's optimized based on real world usage data, rather than just using a canned heuristic set, I think that's worth trying.
-Sven