[Python-3000] the future of the GIL

[Mike Klaas]

On 5/9/07, Talin <talin at acm.org> wrote:

<>
> This much I agree: There's no point in talking about supporting multiple
> processors using threads as long as we're living in a refcounting world.
<>

But python isn't--CPython, though, certainly is.  The CPython
interpreter has enormous stability, backward-compatibility, and speed
expectations to live up to, which makes huge architectural unheavals
an unlikely proposition.

I build multi-machine distributed systems using python (and hence use
multi-process parallelism all the time), but I would still like to
have a GILless CPython.  I don't buy the "multi-processor machines
aren't common" argument (certainly has not been my experience), nor
"threading is inferior to multiple processes as the former is too
hard": neither of these arguments would carry the day if (for
instance) a new python interpreter was created from scratch today.

Instead, the real reason the GIL still lingers in CPython is that such
an architectural change (while maintaining the same performance) is
difficult and _not done_.  No-one has solved this challenge, and until
that happens, talking on mailing lists about how great it would be is
pretty much pointless.  It would probably be more fruitful to start a
new python interpreter project based on a different architecture.
Perhaps you could even write it in python.  I suggest that you call it
"PyPy".

-MIke