This is pretty beside the point. The point is that X not having a GIL doesn't inherently mean Python on X also doesn't have a GIL.

CPython does not have a GIL Global Interpreter Lock GC Garbage Collection phase with --gil-disabled. GraalVM does have a GIL, like CPython without --gil-disabled.

How CPython accomplished nogil in their - the original and reference - fork is described in the topical linked PEP 703.

Yes, I know. What I'm saying is that:

It's possible to have a language that doesn't have a GIL, which you implement Python in, but that Python implementation then has a GIL.

The point being that you can't say things like: Jython is written in Java so it doesn't have a GIL. CPython is written in C so doesn't have a GIL. And so on.

If this isn't clear, I apologize.

Oh okay. Yeah I would say that the Java GC and the ported CPython GIL are probably limits to the performance of any Python in Java implementation.

But are there even nogil builds of CPython C extensions on PyPi yet anyway.

Re: Ghidraal and various methods of Python in Java: https://news.ycombinator.com/item?id=36454485