Enhanced chained and Cuckoo hashing methods for multi-core CPUs

Abstract

A hash table is a fundamental data structure implementing an associative memory that maps a key to its associative value. Besides, the paradigm of micro-architecture design of CPUs is shifting away from faster uniprocessors toward slower chip multiprocessors. In this paper, we propose enhanced chained hashing and Cuckoo hashing methods for modern computers having a lot of CPU cores with exploiting CPU cache line and hardware level lock-free operations. The proposed methods outperform the existing methods in most cases and are very scalable in terms of the number of CPU cores. In addition, their performances do not degrade much even with a high fill factor (e.g., 90 %). Through extensive experiments using Intel 32-core machine, we have shown our proposed methods improve performance compared with the state-of-the-art version of the four exiting major hashing methods of linear, chained, Cuckoo, and Hopscotch.