MEASURING THE REAL-TIME LATENCY OF AN I.MX7D USING XENOMAI AND THE YOCTO PROJECT

Abstract: In this thesis the real-time latency of an i.MX7D processor on a CL-SOM-IMX7 boardis evaluated. The real-time Linux for the system is created using Xenomai with both theI-Pipe patch and thePREEMPT_RTpatch. The embedded distribution is built using theYocto Project and uses a vendor i.MX kernel maintained by NXP. The maximum latency for thecobaltcore is268μsfor user-space tasks with a loadedCPU. These types of tasks have the highest latency of Xenomai's three task categories.A latency measurement of thePREEMPT_RTpatch showed a maximum latency ofwith an idle CPU. Therefore it is concluded that thecobalt412μscore has a lower latencyand is therefore better suited for real-time applications. A comparison is made with other modules and it is found that the latency measured inthis thesis is high compared to for example a Raspberry Pi 3B. The source code and congurations for the project can be found at https://github.com/bracoe/meta-xenomai-imx7d