Resource-Oriented Partitioned Scheduling in Multiprocessor Systems: How to Partition and How to Share?

2018 IEEE Real-Time Systems Symposium (RTSS)

Shi

et al. 2018

Self Cite

Over the years, many multiprocessor locking protocols have been designed and analyzed. However, the performance of these protocols highly depends on how the tasks are partitioned and prioritized and how the resources are shared locally and globally. This paper answers a few fundamental questions when realtime tasks share resources in multiprocessor systems. We explore the fundamental difficulty of the multiprocessor synchronization problem and show that a very simplified version of this problem is N P -hard in the strong sense regardless of the number of processors and the underlying scheduling paradigm. Therefore, the allowance of preemption or migration does not reduce the computational complexity. For the positive side, we develop a dependency-graph approach, that is specifically useful for framebased real-time tasks, in which all tasks have the same period and release their jobs always at the same time. We present a series of algorithms with speedup factors between 2 and 3 under semi-partitioned scheduling. We further explore methodologies and tradeoffs of preemptive against non-preemptive scheduling algorithms and partitioned against semi-partitioned scheduling algorithms. The approach is extended to periodic tasks under certain conditions.

“…The resource-oriented partitioned (ROP) scheduling was proposed by Huang et. al [24] in 2016 and later refined by von der Brüggen et al [44] with release enforcement for a special case.…”

Section: Introductionmentioning

confidence: 99%

Dependency Graph Approach for Multiprocessor Real-Time Synchronization

2018 IEEE Real-Time Systems Symposium (RTSS)

Shi

et al. 2018

Self Cite

“…The view angles should not be limited to the processor-or computation-centric perspective. When there are abundant cores/processors, the bottleneck of the system design becomes the synchronization and the communication among the tasks [16,29]. Different flexibility and tradeoff options to achieve real-time guarantees should be provided in a modularized manner to enable tradeoffs between execution efficiency and timing predictability.…”

Section: Resultsmentioning

confidence: 99%

On the Formalism and Properties of Timing Analyses in Real-Time Embedded Systems

Huang

A Journey of Embedded and Cyber-Physical Systems

et al. 2020

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The advanced development of embedded computing devices, accessible networks, and sensor devices has triggered the emergence of complex cyber-physical systems (CPS). In such systems, advanced embedded computing and information processing systems heavily interact with the physical world. Cyber-physical systems are integrations of computation, networking, and physical processes to achieve high stability, performance, reliability, robustness, and efficiency [26]. A cyberphysical system continuously monitors and affects the physical environment which also interactively imposes feedback to the information processing system. The applications of CPS include healthcare, automotive systems, aerospace, power grids, water distribution, disaster recovery, etc. Due to their intensive interaction with the physical world, in which time naturally progresses, timeliness is an essential requirement of correctness for CPS. Communication and computation of safety-critical tasks should be finished within a specified amount of time, called deadline. Otherwise, even if the results are correctly delivered from the functional perspective, the reaction of the CPS may be too late and have catastrophic consequences. One example is the release of an airbag in a vehicle, which only functions properly if the bag is filled with the correct amount of air in the correct time interval after a collision, even in the worst-case timing scenario. While in an entertainment gadget a delayed computation result is inconvenient, in the control of a vehicle it can be fatal. Therefore, a modern society cannot adopt a technological advance when it is not safe.

“…• Resource Oriented Partitioned PCP (ROP-PCP) [22]: Binds the resources on dedicated processors and schedules tasks using semi-partitioned PCP. • GS-MSRP [41]: THe Greedy Slacker (GS) partitioning heuristic for spin-based locking protocol MSRP [16], using Audsley's Optimal Priority Assignment [2] for priority assignment.…”

Section: Evaluations Setupmentioning

confidence: 99%

Scheduling of Real-Time Tasks With Multiple Critical Sections in Multiprocessor Systems

Shi

et al. 2022

IEEE Trans. Comput.

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The performance of multiprocessor synchronization and locking protocols is a key factor to utilize the computation power of multiprocessor systems under real-time constraints. While multiple protocols have been developed in the past decades, their performance highly depends on the task partition and prioritization. The recently proposed Dependency Graph Approach showed its advantages and attracted a lot of interest. It is, however, restricted to task sets where each task has at most one critical section. In this paper, we remove this restriction and demonstrate how to utilize algorithms for the classical job shop scheduling problem to construct a dependency graph for tasks with multiple critical sections. To show the applicability, we discuss the implementation in LITMUS RT and report the overheads. Moreover, we provide extensive numerical evaluations under different configurations, which in many situations show significant improvement compared to the state-of-the-art.