Embedded Linux as platform enabler for real-time sensor control applications

Abstract

With the recent introduction of the PREEMPT_RT patch into the mainline kernel, the open-source operating system Linux is becoming a more formidable real-time platform. The patch introduces the fully preemptible kernel mode, which can be enabled when building the Linux kernel. This mode increases real-time performance by improving the way real-time tasks preempt lower priority tasks. Sensor control systems are generally dependent on real-time performance, and thus requires such optimizations to meet time constraints. This project considers a series of fully preemptible Linux setups as a prospective platform for sensor control systems, and compares them to reference setups using previous preemption modes. To evaluate the setups, a series of latency measurements have been made at different background load conditions using different schedulers, as well as the impact of CPU-isolation. The measurements show that significant gains in real-time performance can be made using the fully preemptible kernel mode, but also shows that the mode increases overhead for non-real-time tasks.