A one-bit swap object using test-and-sets and a max register

TL;DR

This paper presents a wait-free, linearizable one-bit swap object implementation using a max register and test-and-set bits, with optimized operation steps and potential for read-write register replacement, balancing efficiency and complexity.

Contribution

It introduces a novel wait-free implementation of a one-bit swap object using minimal synchronization primitives, improving efficiency and flexibility over previous methods.

Findings

Each swap operation takes at most three steps.

Replacing primitives with read-write registers increases expected steps to O(max(log n, min(log t, n))).

The implementation is linearizable and wait-free.

Abstract

We describe a linearizable, wait-free implementation of a one-bit swap object from a single max register and an unbounded array of test-and-set bits. Each swap operation takes at most three steps. Using standard randomized constructions, the max register and test-and-set bits can be replaced by read-write registers, at the price of raising the cost of a swap operation to an expected O(max(log n, min(log t, n))) steps, where t is the number of times the swap object has previously changed its value and n is the number of processes.