In safety-critical systems, timing accuracy is the key to achieving precise I/O control. To meet such strict timing requirements, dedicated hardware assistance has recently been investigated and developed. However, these solutions are often fragile, due to unforeseen timing defects. In this paper, we propose a robust and timing-accurate I/O co-processor, which manages I/O tasks using Execution Time Servers (ETSs) and a two-level scheduler. The ETSs limit the impact of timing defects between tasks, and the scheduler prioritises ETSs based on their importance, offering a robust and configurable scheduling infrastructure. Based on the hardware design, we present an ETS-based timing-accurate I/O schedule, with the ETS parameters configured to further enhance robustness against timing defects. Experiments show the proposed I/O control method outperforms the state-of-the-art method in terms of timing accuracy and robustness without introducing significant overhead.

翻译：在安全关键系统中，时序精度是实现精确I/O控制的关键。为满足此类严格的时序要求，近年来专用硬件辅助方案已得到广泛研究与发展。然而，由于不可预见的时序缺陷，现有方案往往存在脆弱性问题。本文提出一种鲁棒且时序精确的I/O协处理器，其通过执行时间服务器（ETS）与两级调度器管理I/O任务。ETS能够限制任务间时序缺陷的影响，调度器则根据ETS的重要性进行优先级分配，从而提供可配置的鲁棒调度架构。基于该硬件设计，我们进一步提出基于ETS的时序精确I/O调度方案，通过优化ETS参数配置以增强对时序缺陷的鲁棒性。实验表明，所提出的I/O控制方法在时序精度与鲁棒性方面均优于现有最优方法，且未引入显著性能开销。