Seems like LuaJIT could offer a "drop-in" performance boost for mod_lua .. ?

http://luajit.org/performance_x86.html

"LuaJIT is API-compatible with Lua 5.1. If you've already embedded Lua into your application, you probably don't need to do anything to switch to LuaJIT, except link with a different library ..."

http://luajit.org/install.html#embed

Regards,