Troy Wolz, Dynetics, Inc.
Mike Santy, Dynetics, Inc.

Modern Hardware-in-the-loop (HWIL) systems often use some combination of open-source software and commodity hardware such as Field Programmable Gate Arrays (FPGA) to reduce system development and maintenance costs. HWIL systems with low-latency requirements will typically leverage FPGA's because software-based approaches using standard Operating Systems (OS) introduce unacceptable and unpredictable latency spikes. However, unexpected latency spikes have been drastically reduced due to recent advances in real-time Linux kernels. This paper presents MORPF, a low-latency software framework based on a Xenomai real-time Linux kernel that enables software-based solutions to applications with computational latency requirements as low as tens of microseconds. The framework uses multiple Central Processing Unit cores, with each core executing a single stage in a pipelined algorithm. MORPF also provides support for fan-out and fan-in patterns to distribute a stage’s work across multiple cores and then collect the results to send down the pipeline. MORPF facilitates high-throughput by executing independent stages in parallel while the Xenomai kernel reduces the communication latency between cores to hundreds of nanoseconds. With the combination of multiple cores and near-negligible communication latency, MORPF provides deterministic execution times through the pipeline that are lower than the unavoidable latency spikes present in a standard OS. Using MORPF, developers can build low-latency high-throughput algorithms in software that are not only more sophisticated than FPGA algorithms, but are also faster to develop.