No proper concurrent threads was of course what I meant. In that light the subinterpreter feature is also not very good, since all sib-interpreters share a GIL

No proper concurrent threads was of course what I meant. In that light the subinterpreter feature is also not very good, since all sib-interpreters share a GIL (but iirc there is a PEP out there that might make python properly multi-core through some kind of CSP-approach and independent subinterpreters).