Building Efficient Concurrent Graph Object through Composition of List-based Set

TL;DR

This paper introduces a generic concurrent directed graph data structure built from list-based sets, supporting efficient thread-safe updates, with proven linearizability and performance comparable to list-based sets.

Contribution

It presents a novel, flexible concurrent graph construction from list-based sets, adaptable to different progress guarantees and proven to be linearizable.

Findings

The construction is linearizable with identified linearization points.

Performance of the concurrent graph matches that of list-based sets.

The approach supports various progress guarantees based on underlying set implementation.

Abstract

In this paper, we propose a generic concurrent directed graph (for shared memory architecture) that is concurrently being updated by threads adding/deleting vertices and edges. The graph is constructed by the composition of the well known concurrent list-based set data-structure from the literature. Our construction is generic, in the sense that it can be used to obtain various progress guarantees, depending on the granularity of the underlying concurrent set implementation - either blocking or non-blocking. We prove that the proposed construction is linearizable by identifying its linearization points. Finally, we compare the performance of all the variants of the concurrent graph data-structure along with its sequential implementation. We observe that our concurrent graph data-structure mimics the performance of the concurrent list based set.