Cross-interpreter support for efficient sharing of frozendicts

[a-reich]

Feature or enhancement

Proposal:

The concurrent.interpreters module for subinterpreters handles sharing/sending values across interpreters with direct sharing of some basic immutable types, and a fallback to pickling others. As an immutable container, tuples are supported (as long as all items are themselves shareable). Similarly, I think it would be good to support sharing frozendict without serialization (if keys & values are shareable).

Because dictionaries are so fundamental and common, having a better and more performant way to share such a mapping would significantly improve the experience of using concurrent.interpreters and InterpreterPoolExecutor.

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

[MazinSharaf]

I'm happy to work on this after some further discussion, but I think this seems good at first glance. Just double-checking, we're sharing frozendict if the contents are safe to share, and otherwise we just fallback to pickling, just like tuples in concurrent.interpreters?

[a-reich]

That's what I had in mind yes, but to be clear I'm commenting merely from the perspective of a user that's followed along the subinterpreter features. I don't have the knowledge to be qualified in judging implementations of the internals.