[senderista]

You might want to check out Bidirectional Linear Probing, which can handle load factor >90% with good performance. I implemented and benchmarked it here: https://github.com/senderista/hashtable-benchmarks. Storing integer keys as their hash values (using a reversible hash function) also helps performance. I implemented a dozen or so 32- and 64-bit reversible integer hash functions in the same repo.

[nosferalatu75]

That's great work. Thanks! Using a reversible hash function is a good idea.

[senderista]

FYI here's a concurrent version of BLP (I haven't implemented it but I stole their simplified insert algorithm): https://pdfs.semanticscholar.org/6d6c/ca94c57d408c0b1164d6ff.... Also see a compact version (concurrent Cleary hash table) by the same authors: https://www.researchgate.net/profile/Alfons_Laarman/publicat....