It's not "Microsoft", it's an experimental side project of two people who happen to work at Microsoft. As I understand it, the core motivation is to explore how far they can get in dragging upstream CPython in a JITwards direction -- so it's written as a extension module for CPython, and it requires a very recent version of CPython (no support for python 2!). The advantage is that it's *extremely* compatible with CPython -- unlike pypy, it handles the latest version of the language, it has the same garbage collection rules, and not only do they get essentially perfect extension module compatibility, they get it with zero speed penalty. They can also potentially explore different compilation strategies (e.g. function at a time) that aren't as easy a fit to pypy's meta-tracing architecture, and can use it as a lever to push CPython to start adding features like dict versioning. The disadvantage versus PyPy obviously is that it's nowhere near as mature, there are reasons to doubt that their optimization strategy could ever be competitive with PyPy's given the need for CPython compatibility, and PyPy could conceivably catch up on the relevant axes (better faster cpyext, python 3 support, etc.) -- though this isn't a given either. Right now I think it makes more sense to think of it as an interesting experiment to watch than as a serious product that one hopes to use. In any case, one can't really get mad at some individuals for investing their spare time in the wrong thing. This is definitely not some strategic initiative from Microsoft-the-company. -n On Jul 21, 2016 3:16 PM, "Phyo Arkar" <phyo.arkarlwin@gmail.com> wrote: Hello PyPy Team; I guess you guys already known. Microsft is starting its own pypy : https://github.com/Microsoft/Pyjion The main reason they mention there is due to weak CPyext support but It is just duplicating work, as you guys are already working on it . Shouldn't microsoft contribute into CPyext work in pypy instead? Regards, Phyo. _______________________________________________ pypy-dev mailing list pypy-dev@python.org https://mail.python.org/mailman/listinfo/pypy-dev