[sudhirj]

For hot code, probably, not the entire language in general. If you're looping through a million numbers doing the same calculation, or maybe rendering markdown in a loop an a lot of text, might hit 10X - the JIT will essentially write the code in C for you, then compile it and run it instead of Ruby.

[jashmatthews]

Another factor is a lot of the hot code, like JSON serialization, DB clients, HTTP parsing, is all already in native C extensions. Performance there is only going to improve a little, although some can be better off as pure Ruby + JIT.

[himom]

Rubinius uses LLVM IR for this. The only problem is rbx is still very slow on startup and interactive use.

Ruby (MRI) will have to reinvent the wheel in order to get a panoply of optimizations that some very smart people have already baked in: like the ability to target almost any platform from the same library.. GCC requires cross-compiling per target.

[jashmatthews]

Didn't Rubinius deprecate their JIT due to a torrent of issues and bugs and have not yet replaced it? Or am I out of date?

[chrisseaton]

Yes Rubinius hasn't had a JIT for years.