PyPy <http://pypy.org> is an alternative implementation of Python
primarily focused on performance.
During a very rough benchmark I made with CosmeticChangesToolkit and a
few pages, it didn't provide significant speed improvements, but it did
work.
Have you ever tested PyPy or used it in production?
Given the importance that MediaWiki people have recently given to HHVM,
what do you think we could/should do on the performance side of the
framework?