Non-blocking Patricia Tries with Replace Operations

TL;DR

This paper introduces a non-blocking Patricia trie supporting concurrent insert, delete, and replace operations, with a wait-free find, enabling efficient, atomic updates and high concurrency in shared-memory systems.

Contribution

It presents a novel non-blocking Patricia trie with atomic replace operations and a wait-free find, improving concurrency and atomicity in shared-memory data structures.

Findings

Supports atomic replace of two locations in the trie.

Achieves high concurrency with non-blocking operations.

Empirically outperforms some existing set implementations.

Abstract

This paper presents a non-blocking Patricia trie implementation for an asynchronous shared-memory system using Compare&Swap. The trie implements a linearizable set and supports three update operations: insert adds an element, delete removes an element and replace replaces one element by another. The replace operation is interesting because it changes two different locations of tree atomically. If all update operations modify different parts of the trie, they run completely concurrently. The implementation also supports a wait-free find operation, which only reads shared memory and never changes the data structure. Empirically, we compare our algorithms to some existing set implementations.