Revisiting Actor Programming in C++

TL;DR

This paper introduces CAF, a C++ actor framework designed for scalable, reliable, and resource-efficient concurrent and distributed applications, demonstrating superior performance over existing frameworks in various scenarios.

Contribution

The paper presents the design and implementation of CAF, a native C++ actor framework with features like message transparency, type safety, and pattern matching, enabling robust distributed systems.

Findings

CAF outperforms existing actor frameworks in scalability and efficiency.

CAF demonstrates effective integration with heterogeneous hardware like GPGPUs.

Performance evaluations show low memory footprint and high throughput up to 64 cores.

Abstract

The actor model of computation has gained significant popularity over the last decade. Its high level of abstraction makes it appealing for concurrent applications in parallel and distributed systems. However, designing a real-world actor framework that subsumes full scalability, strong reliability, and high resource efficiency requires many conceptual and algorithmic additives to the original model. In this paper, we report on designing and building CAF, the "C++ Actor Framework". CAF targets at providing a concurrent and distributed native environment for scaling up to very large, high-performance applications, and equally well down to small constrained systems. We present the key specifications and design concepts---in particular a message-transparent architecture, type-safe message interfaces, and pattern matching facilities---that make native actors a viable approach for many robust, elastic, and highly distributed developments. We demonstrate the feasibility of CAF in three scenarios: first for elastic, upscaling environments, second for including heterogeneous hardware like GPGPUs, and third for distributed runtime systems. Extensive performance evaluations indicate ideal runtime behaviour for up to 64 cores at very low memory footprint, or in the presence of GPUs. In these tests, CAF continuously outperforms the competing actor environments Erlang, Charm++, SalsaLite, Scala, ActorFoundry, and even the OpenMPI.