Building a real-time multi-GPU platform: Robust real-time interrupt handling despite closedsource drivers

Abstract—Architectures in which multicore chips are augmented with graphics processing units (GPUs) have great potential in many domains in which computationally intensive real-time workloads must be supported. How-ever, unlike standard CPUs, GPUs are treated as I/O devices and require the use of interrupts to facilitate communication with CPUs. Given their disruptive nature, interrupts must be dealt with carefully in real-time systems. With GPU-driven interrupts, such disruptiveness is further compounded by the closed-source nature of GPU drivers. In this paper, such problems are considered and a solution is presented in the form of an extension to LITMUSRT called klitirqd. The design of klitirqd targets systems with multiple CPUs and GPUs. In such settings, interrupt-related issues arise that have not been previously addressed. I