On 1/29/2010 4:19 PM, Collin Winter wrote:
On Fri, Jan 29, 2010 at 7:22 AM, Nick Coghlan<ncogh...@gmail.com> wrote:
Agreed. We originally switched Unladen Swallow to wordcode in our 2009Q1 release, and saw a performance improvement from this across the board. We switched back to bytecode for the JIT compiler to make upstream merger easier. The Unladen Swallow benchmark suite should provided a thorough assessment of the impact of the wordcode -> bytecode switch. This would be complementary to a JIT compiler, rather than a replacement for it. I would note that the switch will introduce incompatibilities with libraries like Twisted. IIRC, Twisted has a traceback prettifier that removes its trampoline functions from the traceback, parsing CPython's bytecode in the process. If running under CPython, it assumes that the bytecode is as it expects. We broke this in Unladen's wordcode switch. I think parsing bytecode is a bad idea, but any switch to wordcode should be advertised widely.
Several years, there was serious consideration of switching to a registerbased vm, which would have been even more of a change. Since I learned 1.4, Guido has consistently insisted that the CPython vm is not part of the language definition and, as far as I know, he has rejected any byte-code hackery in the stdlib. While he is not one to, say, randomly permute the codes just to frustrate such hacks, I believe he has always considered vm details private and subject to change and any usage thereof 'at one's own risk'.
tjr _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
