Mar 22, 2025

This shows the projected hashmap filtering efficiencies for a LF 1.5 table, for filters of 1-4 bytes, as a function of fingerprint vs. sentinel bits. At this load factor, 3 sentinel bits is most efficient, with a very slight advantage for 4 bits in the 32 bit filter. The optimal configuration varies slightly by load factor, and of course search rate will increase with load factor and/or decrease with filter size.