Yet, no one in their sane mind uses module on hashing, it's always power of 2 table, so the operation is just: hash & (len -1) which is absolutely trivial. It has been this way for decades.
And yet just here in this article someone asked how it compares to a recent hash implementation that offers non-power of two tables and uses modulo if you let it do that, and I have seen many other recent hash table implementations do so.
But that is also not the only issue: If you use powers of two and resort to bitwise and to pick the bucket, you're even more dependent on a good hash function, which may be impossible to guarantee if implementinf APIs that let the user choose hash function as in the article.
Unless you follow the suggestion in this article and uses this method to pick buckets.
To the contrary almost everybody who knows a bit about DDOS security uses primes, not power's of two.
This has been this way for decades, see the relevant hash tables for glibc, gcc, binutils, ...
