Practical lock-free and wait-free LL/SC/VL implementations using 64-Bit GAS

Abstract

The ideal semantics of the instructions LL/SC/VL (LoadLinked, Store-Conditional, Validate) are inherently immune to the ABA problem which is a fundamental problem that affects most lock-free algorithms. This paper presents practical lock-free and wait-free implementations of arbitrary-sized LL/SC/VL variables using 64-bit GAS (Compare-and-Swap). The implementations improve on Jayanti and Petrovic's 64-bit wait-free implementations by reducing the space overhead per variable to a small constant, and not requiring advance knowledge of the maximum number of participating threads, while maintaining minimal amortized expected time and work complexities. © Springer-Verlag 2004.