[antocuni]

what is the python implementation you are involved with?

I agree with your concerns, HPy tries to address them since the beginning. Basically, there are two distinct compilation modes: - CPython ABI: in this mode, things like HPy_Dup and HPy_Close are translated directly into Py_INCREF and Py_DECREF. The overhead is 0 both in theory and in practice, since all the benchmark that we ran so far confirmed this.

- HPy Universal ABI: in this mode, you introduce the indirections which makes it possible e.g. the debug mode. Our benchmarks indicate a 5-10% overhead, which is in line with what you (and we :)) expected.

So, if you are an extension writer, you will be able to distribute both CPython-opimized and universal binaries