LLTA: A Simplicity-Oriented Open-Source WCET Analyser

2026-09-30

AI Summary

This work addresses the challenge of obtaining trustworthy worst-case execution time (WCET) bounds, as existing analysis tools are often closed-source or lack support for commercial microcontrollers. We present an open-source static WCET analyzer designed for commercial off-the-shelf (COTS) microcontrollers. Adopting a simplicity-first design philosophy, the tool directly parses architecture-specific binaries to estimate WCET, natively supports mainstream chips such as the ESP32-C6, and explicitly reports unsound results arising from hardware or software limitations to ensure transparency. Experimental evaluations successfully derive reliable WCET bounds for both the ESP32-C6 and MSP430 platforms. These results validate the tool’s usability and its advantage of eliminating licensing barriers, demonstrating its suitability for real-time systems education and engineering practice.

Abstract

Deriving a safe upper bound on the worst-case execution time (WCET) of a real-time task is essential for hard real-time systems. Many WCET analysers exist, but they are either (i) closed source or (ii) do not provide a WCET for an existing microcontroller. Hence, it is difficult to obtain a trustworthy WCET bound for the binary that is flashed to an available embedded hardware platform and to observe whether the bound is safe. To solve this, we present LLTA, an open-source WCET analyser for Commercial-Off-The-Shelf (COTS) microcontrollers. LLTA is designed based on the following goals: it is simple (G1), runs on real COTS hardware (G2), reports results that are unsound due to programming or device constraints (G3), and is available open-source without licensing complications (G4). LLTA generates WCETs for the ESP32-C6 and the MSP430(FR5994), which are broadly available. This paper systematically lays out our design decisions for LLTA with those goals in mind. To demonstrate its ease of use, we propose scenarios where LLTA can be used for lab exercises of real-time systems.

Problem

• Worst-Case Execution Time
• Real-Time Systems
• Microcontrollers
• Open-Source
• Embedded Hardware

Innovation

• Worst-Case Execution Time
• Open-Source
• COTS Microcontrollers
• Real-Time Systems
• WCET Analysis