You can have cache-unfriendly hash functions, though. For example, a common optimisation for CRC implementation involves lookup tables. If your lookup table ex

You can have cache-unfriendly hash functions, though. For example, a common optimisation for CRC implementation involves lookup tables. If your lookup table exceeds L1 then you're going to have a bad time. If your lookup table fits exactly in L1, your benchmarks might look great, while real-world performance suffers (because your other code wants to be making use of L1, too). I'd imagine rapidhash avoids lookup tables but the question of cache-friendliness is still pertinent.