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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: Good hash for pointers
Date: Sat, 25 May 2024 10:40:22 -0700
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Bonita Montero <Bonita.Montero@gmail.com> writes:

> Am 25.05.2024 um 11:12 schrieb Tim Rentsch:
>
>> Your hash function is expensive to compute, moreso even
>> than the "FNV" function shown earlier.  In a case like
>> this one where the compares are cheap, it's better to
>> have a dumb-but-fast hash function that might need a
>> few more looks to find an open slot, because the cost
>> of looking is so cheap compared to computing the hash
>> function.
>
> A (size_t)pointer * LARGE_PRIME can be sufficient,
> ignoring the overflow.

Plenty fast but the output quality is poor.  I tested
this scheme against four other hash functions, and in
four out of five workloads it was always dead last, by
a noticeable margin.