Suitability for Real-Time Applications

Whether the presented system is suitable for practical usage is depended on the application. The measurements overall give a good reference for a wide variety of practical applications that stress the system in different ways. However, slightly differently configured, or selected stressors might have given different results. Likewise, it should be noted that cyclictest can give somewhat optimistic numbers, so that would need to be carefully considered when referencing these numbers for real-world usage. Even the cyclictest utility itself can interfere with the latency measurements. In addition, the used minimal real-time kernel is certainly not representative of practical applications, so changing the configuration might bring up additional challenges.

Regardless, already at this point, without any significant architecture-specific latency optimizations the system appears to achieve acceptable latencies. The current system can be considered soft or firm but certainly not hard real-time capable. This means that in theory, the presented system would be suitable for industrial machinery, but in practice, official support by PREEMPT_RT with extensive prior experience would be required. Starting from kernel v6.6, RT-Linux officially supports RISC-V architecture.

Other properties of RISC-V, of course, provide some appealing benefits in comparison to other architectures for industrial applications. It is a completely open ecosystem, and for example, it is easier to develop completely custom instruction-level extensions. The RISC-V ecosystem is also very modern as there is not any legacy burden on the system. All these aspects might very well make a Real-Time Linux running on the RISC-V platform a desirable system for some use cases in the future.