Love for LuaJIT

The last few years have been an exciting time for dynamic language implementations. The latest generation of JavaScript engines – Mozilla TraceMonkey, WebKit SquirrelFish Extreme, and Google's own V8 – are all based on just-in-time (JIT) compilation, which has led to dramatic speedups for web applications. The Unladen Swallow project is building a JIT for Python based on LLVM. But you may not have heard of the dynamic language Lua or the one-man LuaJIT project, which released a beta of its long-awaited 2.0 two months ago, along with some very impressive benchmarks.

LuaJIT is developed by Mike Pall, an open source developer located in Germany. Since its first release in 2005, LuaJIT has been at the forefront of dynamic language performance. In 2008 Mike announced that he was working on a complete rewrite based on trace compiler technology. It breaks with a long tradition of method-at-a-time JIT compilers and seems especially well suited for compiling dynamic languages. As LuaJIT shows, this approach yields performance that can rival even offline, static language compilers.

We use Lua internally at Google, and are very happy to be sponsoring the port of LuaJIT 2.0 to x86-64 (the initial release was for 32-bit x86 only). The full list of sponsors can be found on the LuaJIT sponsors page. The x86-64 port will be released under the MIT/X license, just as previous LuaJIT releases have been. Many thanks to Mike Pall for his excellent work on LuaJIT.

by Joshua Haberman, Software Engineering Team