[Armin Rigo] ...
Why it is related to Psyco: the current treatment of globals/builtins makes it hard for Psyco to statically tell what function we are calling when it sees e.g. "len(a)" in the code. We would at least need some help from the interpreter; at least hooks called when the module's globals() dictionary change. The above proposal might provide a more uniform solution.
FYI, a different proposal for opt. globals access by Jeremy Hylton. It seems, it would break fewer things ... don't know whether it can be as useful for Psyco:
In any case I think Psyco will need notification support from the interpreter about dynamic changes to things that Psyco honestly assumes to be invariant in order to achieve performance.
regards, Samuele Pedroni.