[pypy-dev] connecting multiple interpreters (was: Re: change of strategy for the py3k branch?)

[holger krekel]

Hi Armin, Martijn,

On Mon, Jun 04, 2012 at 15:33 +0200, Armin Rigo wrote:
> Hi Martijn, hi Holger,
> 
> On 6/1/12, Martijn Faassen <faassen at startifact.com> wrote:
> > Concerning performance overhead of proxies, lifecycle issues would be
> > tricky
> 
> If, hypothetically speaking, there is someone interested in writing a
> PyPy solution where both a Python2 and a Python3 interpreter are
> running in the same process, then you gain the advantage of having
> only one GC to run both.  At least it transparently solves the issues
> of lifetime and reference cycles.  (You also have for free only one
> JIT, which can do cross-language optimizations like inlining a Python2
> function into a Python3 context or vice-versa).  I see these two
> points as benefits that you don't have in any multi-process solution.
> 
> It would require some work on the PyPy side, and I'm not aware of
> anybody ready to invest time in that, but it shouldn't be particularly
> hard (once PyPy's Python3 interpreter is ready, and once people agree
> about which API to use to do cross-language calls.)

Good point, PyPy could indeed bring considerable performance and
resource benefits and avoid distributed GC issues.  Of course there also are
deployment and API questions that could maybe better first be tackled outside
of PyPy in the form of a prototype that ignores GC issues.

I am wondering, however, how many people really have that py2/py3 need 
and how much they care about performance in such situations. OTOH,
a good solution could trigger needs - that's how a lot of technology 
development works, anyway :)

best,
holger


> A bientôt,
> 
> Armin.
>