unladen swallow: python and llvm

[Paul Rubin]

bearophileHUGS at lycos.com writes:
> What I like of Unladen swallow is that it's a very practical approach,
> very different in style from ShedSkin and PyPy (and it's more
> ambitious than Psyco). I also like Unladen swallow because they are
> the few people that have the boldness to do something to increase the
> performance of Python for real.

IMHO the main problem with the Unladen Swallow approach is that it
would surprise me if CPython really spends that much of its time
interpreting byte code.  Is there some profiling output around?  My
guess is that CPython spends an awful lot of time in dictionary
lookups for method calls, plus incrementing and decrementing ref
counts and stuff like that.  Plus, the absence of a relocating garbage
collector may mess up cache hit ratios pretty badly.  Shed Skin as I
understand it departs in some ways from Python semantics in order to
get better compiler output, at the expense of breaking some Python
programs.  I think that is the right approach, as long as it's not
done too often.  That's the main reason why I think it's unfortunate
that Python 3.0 broke backwards compatibility at the particular time
that it did.