[aartur]

I run the benchmark using PyPy (which doesn't have this C extension) and got a result about 20% slower compared to CPython (ie. still faster than Go).

EDIT. I also did a funny thing and replaced the CPython C _csv.so extensions with pure Python version _csv.py, from PyPy. It run about 80 (eighty) times slower. It shows what wonders does JIT do (at least to some code).

[jjawssd]

Would be a great experiment to Cythonize PyPy's _csv.so

[chrisseaton]

PyPy doesn't have a _csv.so - that was the main point of the comment you replied to.

[masklinn]

That sounds completely worthless, PyPy doesn't need a Cython version, and its library is a Python version of CPython's native csv module.