A Concurrent Dictionary and Wait-Free Queue from Compare and Swap

This paper describes algorithms for a lock-free dictionary and a waitfree queue. The queue improves on a previous result by Kogan and Petrank by not requiring Stop-The-World Garbage Collection. The lock-free dictionary is structured as a multi-level hash table to avoid global resize. It can be made wait-free for most practical key types with trivial modifications. The dictionary supports sequentially consistent compare and swap operations in addition to exchange and put, but does not support removal. It was over 3 times faster than a previous concurrent multi-level hash table result. The data structures in this paper expect a compare and swap primitive, found in many commodity architectures including x86, x64, and Itanium.