Ruby Enterprise Edition is a server-oriented friendly branch of Ruby which includes various enhancements:
- A copy-on-write friendly garbage collector. Phusion Passenger uses this, in combination with a technique called preforking, to reduce Ruby on Rails applications' memory usage by 33% on average.
- An improved memory allocator called tcmalloc, which improves performance quite a bit.
- The ability to tweak garbage collector settings for maximum server performance, and the ability to inspect the garbage collector's state. (RailsBench GC patch)
- The ability to dump stack traces for all running threads (caller_for_all_threads), making it easier for one to debug multithreaded Ruby web applications.