Resource Synchronization Protocols And Design Optimization Techniques For Mixed-criticality CPS

In Today’s complex Cyber-Physical Systems(CPS), designers often need to in-tegrate multiple applications with varying levels of criticality on the same hardware platform to form a Mixed-Criticality System. Mixed-Criticality Scheduling (MCS) is a type of real-time scheduling algorithm for Mixed-Criticality Systems. In this thesis, we address two aspects of MCS, including resource synchronization protocols and design optimization algorithms.A common assumption adopted by researchers on MCS is that tasks with differ-ent criticality levels are independent and do not share common resources (e.g., global data variables). This assumption is helpful for reducing mutual interference among tasks with different criticality levels and simplifies system design and safety certifi-cation. However, for certain cases, tasks with different criticality levels may need to share resources and communicate with each other, especially among the lower-critical levels. Therefore, if we can provide effective analysis algorithms theory support, it will help broaden the applicability of MCS in real systems. In order to support re-source sharing among tasks with different criticality levels while guaranteeing real-time schedulability, we developed real-time resource synchronization protocols and their schedulability analysis algorithms, for both Fixed-Priority (FP) and Earnest Deadline First (EDF) algorithms on uniprocessor.The initial application context that MCS was proposed for was the aerospace and avionics systems. Due to the many similarities between automotive and avion-ics electronics, especially the trend of hardware platform consolidation and integra-tion, recently researchers have proposed to apply MCS to automotive electronic con-trol systems. Since automobiles are mass-produced consumer products, the hyper-competitive market pressure forces the automotive industry to be very cost-sensitive, making it very important to reduce system hardware cost by adopting resource- constrained (including CPU speed and memory) low-cost processors. In contrast, the aerospace industry is much less cost-sensitive, hence research on MCS have not placed enough emphasis on hardware resource optimization issues. In order to op-timize (minimize) system memory resource requirements, we integrate Preemption Threshold Scheduling (PTS) with MCS, for both Fixed-Priority (FP) and Earliest Deadline First (EDF) algorithms on uniprocessor.Specifically, this thesis includes the following work:· Resource synchronization protocol for Fixed-Priority(FP)-based MCS:Based on Priority Ceiling Protocol (PCP) for FP scheduling algorithm, we propose the resource synchronization protocol HLC-PCP (Highest-Locker Criticality, Priority-Ceiling Protocol) for Adaptive Mixed-Criticality (AMC), and its schedu-lability analysis.· Resource synchronization protocol for Earliest Deadline First(EDF)-based MCS:Based on Stack Resource Protocol (SRP) for EDF scheduling algorithm, we propose the resource synchronization protocol MC-SRP (Mixed-Criticality Stack Resource Protocol) for Dual-Deadline scheduling algorithm, and its schedulability analysis.· Design optimization techniques for FP-based resource-constrained mixed-criticality systems:We integrate Preemption Threshold Scheduling (PTS) with Adaptive Mixed-Criticality for FP scheduling, and propose PT-AMC (Preemp-tion Threshold-Adaptive Mixed-Criticality) and its schedulability. In addition, we reduce system stack space requirement while guaranteeing schedulability by optimizing task priorities and preemption threshold values.·Design optimization techniques for EDF-based resource-constrained mixed-criticality systems:We integrate Preemption Threshold Scheduling (PTS) with Dual-Deadline scheduling algorithm for EDF scheduling, and propose MC-SRPT (Mixed-Criticality Stack Resource Protocol Threshold) and its schedu- lability analysis. In addition, we reduce system stack space requirement while guaranteeing schedulability by optimizing task priorities and preemption thresh-old values.