[Python-Dev] Fwd: Removal of GIL through refcounting removal.

Neil Schemenauer nas at arctrix.com
Fri Oct 31 02:27:12 CET 2008

Sigurd Torkel Meldgaard <stm at daimi.au.dk> wrote:
> For a student project in a course on virtual machines, we are
> evaluating the possibility to experiment with removing the GIL
> from CPython


It's great to hear of this kind of project.  I think what you want
to do is difficult but possible.  The major compilcation would be
that extension modules would have to re-written since they all
assume a reference counting GC.  A foreign function interface like
CMU Lisp's "alien" or GHC's FFI is not necessarily any worse but it
does place different demands on extension module authors. 

As a student project, I think it would make sense to forget about
extensions and try to create a barebones interpreter based on
CPython's runtime, compiler, etc with the reference counting ripped
out and some other GC installed.

I once had the Boehm GC working with Python.  That's not too
interesting.  I'm not really up-to-date on current GC research but I
think your GC has to do some copying in order to get really good
performance.  Producing a barebones version of the Python
interpreter that utilizes a modern, copying GC would be a nice
achievement and could be a platform for future work.



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