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Enabling CPython multi-core parallelism via subinterpreters.
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LICENSE Initial commit Aug 17, 2018 Update Aug 24, 2018


Enabling CPython multi-core parallelism via subinterpreters.

This repo is for tracking the effort and as a place to keep any tooling.

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Project Summary

From my python-ideas post (June 2015):

Python's multi-core story is murky at best.  Not only can we be more
clear on the matter, we can improve Python's support.  The result of any
effort must make multi-core (and concurrency) support in Python obvious,
unmistakable, and undeniable (and keep it Pythonic).

The goal of this project is to do just that, by using the existing subinterpreter C-API.


The minimal multi-core solution will involve:

  • resolving existing bugs and blockers
  • exposing the existing support (from C-API) in a stdlib module
  • adding a mechanism to safely "share" basic immutable objects between interpreters
  • no longer sharing the GIL between interpreters

Once a minimal solution is in place we can expand from there.

At a high level, we're doing the following concrete tasks:

Constraints / Requirements

  1. no significant impact on single-threaded performance
  2. maintain backward compatibility (C-API, etc.)
  3. (pseudo-)compatibility with multiprocessing/threading/concurrent.futures APIs
  4. a multi-core concurrency model/approach that fits our brains
  5. Python APIs
  6. supportable on other Python implementations
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