Embedded Rust or C Firmware? Lessons from an Industrial Microcontroller Use Case with Ariel OS

TL;DR

This study compares Rust and C for microcontroller firmware in an industrial IoT case, finding Rust's ecosystem is mature enough to match C in performance and efficiency, with Ariel OS supporting Rust's viability.

Contribution

It provides empirical evidence that Rust is a practical and efficient alternative to C for microcontroller firmware development, supported by a real-world case study.

Findings

Rust and C have comparable memory and speed performance.

Ariel OS enables a smaller footprint in Rust firmware.

Rust is a viable choice for industrial microcontroller firmware.

Abstract

As Rust gains traction for developing safer systems software, a reality check for the microcontroller hardware segment becomes necessary. How ready is the Rust ecosystem for this segment? Can Rust compete with C in practice? This paper reports on an IoT industrial case study that contributes to answering these questions. Two teams concurrently developing the same functionality (one in C, one in Rust) are analyzed over a period of several months. A comparative analysis of their approaches, results, and iterative efforts is provided. The analysis and measurements on hardware indicate no strong reason to prefer C over Rust for microcontroller firmware on the basis of memory footprint or execution speed. Furthermore, Ariel OS is shown to provide an efficient and portable system runtime in Rust whose footprint is smaller than that of the state-of-the-art bare-metal C stack traditionally used in this context. It is concluded that Rust is a sound choice today for firmware development in this domain.