Comment by lopuhin
I think GraalPython does have a GIL, see https://github.com/oracle/graalpython/blob/master/docs/contr... - and if by "there is no such thing on those platforms" you mean JVM/CLR not having a GIL, C also does not have a GIL but CPython does.
My mistake, as I assumed they took the same decision as jython and IronPython.
https://jython.readthedocs.io/en/latest/Concurrency/#no-glob...
https://wiki.python.org/moin/IronPython
The difference between JVM, CLR and C in regards to parallel and concurrent code is that they are built for those kind of workloads, and have a memory model proper, hence not needing a GIL.