To make this more interesting (as well as to run the latency test on a constrained system), we shall perform latency measurements using the well-known cyclictest app – while the system is under some amount of load (via the stress(1) utility) – on the equally well-known Raspberry Pi device. This section is divided into four logical parts:
- First, set up the working environment on the Raspberry Pi device.
- Second, download and apply the RT patches on the kernel source, configure, and build it.
- Third, install the cyclictest app, as well as a few other required packages (including stress), on the device.
- Fourth, run the test cases and analyze the results (even plotting graphs to help do so).
The first step and most parts of the second have already been covered in detail in Chapter 3, Building the 5.x Linux Kernel from Source – Part 2, in the Kernel build for the Raspberry Pi section. This includes...