Timing-Accurate General-Purpose I/O for Multi- and Many-Core Systems: Scheduling and Hardware Support

General-purpose I/O widely exists on multi- and many-core systems. For real-time applications, I/O operations are often required to be timing-predictable, i.e., bounded in the worst case, and timing-accurate, i.e., occur at (or near) an exact desired time instant. Unfortunately, both timing requirements of I/O operations are hard to achieve from the system level, especially for many-core architectures, due to various latency and contention factors presented in the path of instigating an I/O request. This paper considers a dedicated I/O co-processing unit, and proposes two scheduling methods, with the necessary hardware support implemented. It is the first work that guarantees timing predictability and maximises timing accuracy of I/O tasks in the multi-and many-core systems.