The Partitioned Multiprocessor Scheduling of Sporadic Task Systems

Baruah, Sanjoy; Fisher, Nathan

doi:10.1109/rtss.2005.40

Cited by 96 publications

(68 citation statements)

References 10 publications

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“…Such an assignment (and correspondingly, the number of processors required for C hrt ) can be determined using any of various bin-packing heuristics. Further results concerning PEDF schedulability tests can be found in (Baruah and Fisher, 2005;Chakraborty and Thiele, 2005;Liu, 2000). As mentioned earlier, HRT policies may introduce utilization loss.…”

Section: Subproblemmentioning

confidence: 99%

A hierarchical multiprocessor bandwidth reservation scheme with timing guarantees

Leontyev

Anderson

2009

Real-Time Syst

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A multiprocessor scheduling scheme is presented for supporting hierarchical containers that encapsulate sporadic soft and hard real-time tasks. In this scheme, each container is allocated a specified bandwidth, which it uses to schedule its children (some of which may also be containers). This scheme is novel in that, with only soft real-time tasks, no utilization loss is incurred when provisioning containers, even in arbitrarily deep hierarchies. Presented experiments show that the proposed scheme performs well compared to conventional real-time scheduling techniques that do not provide container isolation.

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Section: Subproblemmentioning

confidence: 99%

A hierarchical multiprocessor bandwidth reservation scheme with timing guarantees

Leontyev

Anderson

2009

Real-Time Syst

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“…The tasks are usually partitioned using polynomial time heuristic algorithms such as, first-fit, worst-fit and best-fit. In [9], Baruah et al present an optimized first-fit partitioning algorithm. The key idea of the algorithm is to assign tasks to processor bins such that the tasks assigned to the processors create a feasible schedule.…”

Section: Classification Based On Degree Of Task Migrationmentioning

confidence: 99%

“…The key idea of partitioned scheduling is to divide the task-set using an off-line heuristic, as partitioning a set of tasks on M processors has been shown to be equivalent to the bin-packing problem [46] and hence NP-hard in the strong sense. Baruah et al present a polynomial-time algorithm to partition collection of sporadic tasks onto a M processors in [8]. Figure 5.5 illustrates the partitioned scheduling approach used in ChronOS.…”

Section: Partitioned Schedulingmentioning

confidence: 99%

“…In Figure 5.9 tasks RT 5 , RT 8 , RT 1 and RT 4 represent four real-time tasks that have been selected by the global scheduling algorithm at the end of a scheduling event. In order to understand the mapping algorithm we give a snapshot of the per-processor run-queues.…”

Section: Mapping Tasks To Processorsmentioning

confidence: 99%

“…In order to partition the tasks on to the processors, we implement Baruah's first-fit partitioning algorithm [9] to divide the task-sets off-line into processor bins. The algorithm uses the EDF schedulability criteria and assigns tasks to processors such that the resultant task-set is feasible on that processor.…”

Section: Comparison With Partitioned Scheduling Algorithmsmentioning

confidence: 99%

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On Best-Effort Utility Accrual Real-Time Scheduling on Multiprocessors

Garyali¹,

Dellinger²,

Ravindran³

2010

Lecture Notes in Computer Science

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We consider the problem of scheduling real-time tasks on a multiprocessor system. Our primary focus is scheduling on multiprocessor systems where the total task utilization demand, U , is greater than m, the number of processors on a multiprocessor system-i.e., the total available processing capacity of the system. When U > m, the system is said to be overloaded; otherwise, the system is said to be underloaded. While significant literature exists on multiprocessor real-time scheduling during underloads, little is known about scheduling during overloads, in particular, in the presence of task dependencies-e.g., due to synchronization constraints. We consider real-time tasks that are subject to time/utility function (or TUF) time constraints, which allow task urgency to be expressed independently of task importance-e.g., the most urgent task being the least important. The urgency/importance decoupling allowed by TUFs is especially important during overloads, when not all tasks can be optimally completed. We consider the timeliness optimization objective of maximizing the total accrued utility and the number of deadlines satisfied during overloads, while ensuring task mutual exclusion constraints and freedom from deadlocks. This problem is NP-hard. We develop a class of polynomial-time heuristic algorithms, called the Global Utility Accrual (or GUA) class of algorithms.The algorithms construct a directed acyclic graph representation of the task dependency relationship, and build a global multiprocessor schedule of the zero in-degree tasks to heuristically maximize the total accrued utility and ensure mutual exclusion. Potential deadlocks are detected through a cycle-detection algorithm, and resolved by aborting a task in the deadlock cycle. The GUA class of algorithms include two algorithms, namely, the Non-Greedy Global Utility Accrual (or NG-GUA) and Greedy Global Utility Accrual (or G-GUA) algorithms. NG-GUA and G-GUA differ in the way schedules are constructed towards meeting all task deadlines, when possible to do so. We establish several properties of the algorithms including conditions under which all task deadlines are met, satisfaction of mutual exclusion constraints, and deadlock-freedom.We create a Linux-based real-time kernel called ChronOS for multiprocessors. ChronOS is extended from the PREEMPT RT real-time Linux patch, which provides optimized interrupt service latencies and real-time locking primitives. ChronOS provides a scheduling framework for the implementation of a broad range of real-time scheduling algorithms, including utility accrual, non-utility accrual, global, and partitioned scheduling algorithms.We implement the GUA class of algorithms and their competitors in ChronOS and conduct experimental studies. The competitors include G-EDF, G-NP-EDF, G-FIFO, gMUA, P-EDF and P-DASA. Our study reveals that the GUA class of algorithms accrue higher utility and satisfy greater number of deadlines than the deadline-based scheduling algorithms by as much as 750% and 600%, respectively. In addition, ...

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Techniques for Building Timing-Predictable Embedded Systems

Guan

2016

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The Partitioned Multiprocessor Scheduling of Sporadic Task Systems

Cited by 96 publications

References 10 publications

A hierarchical multiprocessor bandwidth reservation scheme with timing guarantees

A hierarchical multiprocessor bandwidth reservation scheme with timing guarantees

On Best-Effort Utility Accrual Real-Time Scheduling on Multiprocessors

Techniques for Building Timing-Predictable Embedded Systems

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