Cuckoo hashing with pages

Abstract

A downside of cuckoo hashing is that it requires lookups to multiple locations, making it a less compelling alternative when lookups are expensive. One such setting is when memory is arranged in large pages, and the major cost is the number of page accesses. We propose the study of cuckoo hashing with pages, advocating approaches where each key has several possible locations, or cells, on a single page, and additional choices on a second backup page. We show experimentally that with k cell choices on one page and a single backup cell choice, one can achieve nearly the same loads as when each key has k∈+∈1 random cells to choose from, with most lookups requiring just one page access, even when keys are placed online using a simple algorithm. While our results are currently experimental, they suggest several interesting new open theoretical questions for cuckoo hashing with pages. © 2011 Springer-Verlag Berlin Heidelberg.