> 5) Reverted changes in Objects/descrobject.c. They added a regression in
> namedtuple attributes access.
Oh, I now understand. The change makes "namedtuple.attr" slower. With fastcall-3.patch attached to this issue, the fast path is not taken on this benchmark, and so you loose the removed optimization (tuple cached in the modified descriptor function).
In fact, you need the "full" fastcall change to make this attribute lookup *faster*:
https://bugs.python.org/issue26814#msg263999
So yeah, it's better to wait until more changes are merged.