Version 2.2 of the PyPy implementation of the Python 2 language is out. "Our Garbage Collector is now 'incremental'. It should avoid almost all pauses due to a major collection taking place. Previously, it would pause the program (rarely) to walk all live objects, which could take arbitrarily long if your process is using a whole lot of RAM. Now the same work is done in steps." There have also been improvements to the JIT compiler, the NumPy module has been split out, and various other changes have been made.