Reprogramming of Embedded Devices using Zephyr: Review and Benchmarking

The Internet of Things is driving a new technological revolution using wirelessly connected devices to sense and actuate in many use cases of our daily lives. The development of firmware and software for this kind of device requires specialized developers and updating them after deployment is still an open field topic. This paper aims to address these issues by researching and testing solutions that can isolate functionalities, minimize the size of updates, and facilitate deployments. A set of solutions are compared in terms of performance, update time, power consumption and memory footprint. Results show that scripting based approaches allow easy programming of the devices but are 270x slower than native code while consuming 75% more power. Virtual machines, although not as slow, still incur a slowdown of around 200x. Dynamic loading of native code shows the best trade-off between versatility and performance since they are only 2x times slower than native code. All approaches offer massive reductions in update size and time, with improvements of 30x and 700x, respectively. The results allow us to conclude that all solutions are valid but target different challenges and the use case for each one needs to be carefully studied due to several trade-offs.