Timerlat: Real-Time Linux Scheduling Latency Measurements, Tracing, and Analysis

A trend in many embedded devices is the move from hardware-based to software-defined, such as software-defined networks and software-defined PLCs. This trend is motivated by multiple aspects, including the availability of complex software stacks and the consolidation of multiple devices into a single larger system. Due to its real-time capabilities and flexibility, Linux is the operating system of choice for many applications, including time-sensitive ones. However, assessing and debugging timing violations, especially those caused by scheduling latency, is challenging with the current state-of-the-art tools. This paper presents <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">timerlat</monospace>, a tool that integrates scheduling latency measurements, tracing, and analysis in an easy-to-use interface. Its output includes an auto-analysis, providing insightful details on the composition of the scheduling latency. Experimental results are reported, evaluating the effectiveness of timerlat in assessing the latencies, considering different setups and workloads.