There's a trivial optimization in the round_size in hashtable.c:
a loop is used to compute the lowest power of two >= s,
while this can be done in one step with bit_length.
I am making a pull request for this.

Do you have any benchmarks?

I'd be especially curious about branch (mis)prediction stats before and after applying this patch – including such information seems necessary in a patch that's about optimization.

Since no benchmarking data was provided, I suggest to close this issue. We do not accept optimization changes without evidences of performance boost.

Harsh, but fair.
I'll do a better job next time!

Op di 29 dec. 2020 13:42 schreef Serhiy Storchaka <report@bugs.python.org>:

>
> Serhiy Storchaka <storchaka+cpython@gmail.com> added the comment:
>
> Since no benchmarking data was provided, I suggest to close this issue. We
> do not accept optimization changes without evidences of performance boost.
>
> ----------
> status: open -> pending
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <https://bugs.python.org/issue42673>
> _______________________________________
>

Closing as it sounds like OP agreed to it in the last msg; and no benchmarking was provided.