If you're calling into C, you can disable the GIL from C for the duration of the call. You have to re-enable it again before the call returns and you have to be

If you're calling into C, you can disable the GIL from C for the duration of the call. You have to re-enable it again before the call returns and you have to be careful not to call any of the Python C API calls that rely on the GIL (reference counting and such for sure). Of course, if you want to do this, you can't simply call into a random C library directly but have to write a C stub.