From: Kent Overstreet > Sent: 25 February 2024 03:19 .. > when I implemented cuckoo (which is more obviously sensitive to a weak > hash function), I had to go with siphash, even jhash wasn't giving me > great reslts. and looking at the code it's not hard to see why, it's all > adds, and the rotates are byte aligned... you want mixed adds and xors > and the rotates to be more prime-ish. > > right idea, just old... > > what would be ideal is something more like siphash, but with fewer > rounds, so same number of instructions as jhash. xxhash might fit the > bill, I haven't looked at the code yet... There is likely to be a point where scanning a list of values for the right hash value is faster than executing a hash function that is good enough to separate them to separate buckets. You don't want to scan a linked list because they have horrid cache footprints. The locking is equally horrid - especially for remove. Arrays of pointers ar ethe way forward :-) David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
