Robust Real-Time Multiprocessor Interrupt Handling Motivated by GPUs

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. However, 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 LITMUS^RT called klmirqd. The design of klmirqd targets systems with multiple CPUs and GPUs. In such settings, interrupt-related issues arise that have not been previously addressed.