Twist: Lua makes it trivial to overload arithmetic using metatables, but LuaJIT seems to have solved that. If there is any warmup time, it's hard to tell. Mike Pall is a JIT god, and I wish we had more insight into everything that went into producing one of the best JIT's of all time.

I'd love a comment/post that highlights the differences between JS and Lua as the reason why LuaJIT was able be so effective. There must be differences that make Lua possible to speed up so much. There are easy ones to think of, but the details matter a lot.

EDIT: I found some discussion at https://news.ycombinator.com/item?id=1188246 but it left me wanting more.

Related:

https://stackoverflow.com/questions/4911762/why-is-luajit-so...

http://article.gmane.org/gmane.comp.lang.lua.general/58908

http://lua-users.org/lists/lua-l/2010-03/msg00305.html