That's pretty surprising, because I have also extensively used PyO3 in my daily job and it was quite performant. Your comment does seem to suggest that you were

That's pretty surprising, because I have also extensively used PyO3 in my daily job and it was quite performant. Your comment does seem to suggest that you were also using the `numpy` crate or similar in addition to `pyo3`, which performance might be more variable than I would expect for PyO3 though. (I personally minimized the use of `numpy` for that reason, but didn't have a particular performance issue with it anyway.)