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1.
丁万夫  郭锐锋  秦承刚  刘娴  郭凤钊 《软件学报》2011,22(12):2894-2904
基于软件容错模型,提出了允许容错优先级提升的抢占阈值容错调度算法(extended fault-tolerantfixed-priority with preemption threshold,简称FT-FPPT*).该算法能够在抢占式容错调度算法(fault-tolerantfixed-priority preemptive,简称FT-FPP)和抢占阈值容错调度算法(fault-tolerant fixed-priority with preemptionthreshold,简称FT-FPPT)无法提高系统容错能力的情况下,进一步提高系统的容错能力.为了获得系统中任务优先级分配的最佳策略,基于任务最坏响应时间的可调度性分析,提出了一种最优的优先级配置搜索算法(priorityassignment search algorithm,简称PASA).经过深入分析和实验证明,与FT-FPPT算法相比,FT-FPPT*算法能够有效地提高硬实时系统的容错能力.  相似文献   

2.
In this paper, we study the adequacy of available schedulability tests for monoprocessor fixed-priority systems to enable performing scheduling analysis for automotive applications. We show that, in spite of the work carried out during the last decade to enhance these tests in order to support more realistic task model, a gap still exists between the task model considered in these tests and the usual automotive task model. However, we claim that an extension of these tests is possible to support some of the uncovered automotive features. The aim of this study is to raise discussion and make researchers involved in the development of such schedulability tests be aware of the effort needed to bridge the gap between current schedulability tests and automotive task model mostly used. The study is illustrated by showing the concrete challenges faced when applying scheduling analysis to a case study derived from a real engine control application.  相似文献   

3.
受到广泛关注的抢占阈值调度算法能够有效减少现场切换次数,防止不必要的任务抢占,降低资源额外消耗,提高任务集合的可调度性.目前该调度算法的研究工作大多围绕独立任务集合展开,在实际实时系统中任务经常需要互斥访问共享资源,任务之间由于资源共享而导致的相关性对于任务集合的优先级分配和抢占阈值分配都有很大的影响.SRP协议是在实时系统中得到广泛应用的资源访问控制协议,具有死锁避免、提前阻塞、共享任务栈等一系列优良特性.将SRP和抢占阈值调度算法结合起来,提出FPTS调度模型,给出相应的可调度性判定公式,考虑在任务之间使用SRP协议时求解任务抢占阅值分配,最后给出计算抢占阈值分配的伪多项式时间算法.  相似文献   

4.
目前实时CORBA在电信、电子商务、证券、复杂工业控制等领域发挥着越来越重要的作用。针对这些应用的特点,首先论述了分布式中间件和分布式应用开发对多线程的需求,再在实时CORBA的基础上,设计并用C++实现了一个具有Java风格的面向对象的平台依赖层,它能够在不同的平台上运行,可以把CORBA优先级映射为本地优先级,具有固定优先级的调度策略,在提供灵活的线程管理的同时,能够有效地防止优先级反转。  相似文献   

5.
Chen  Ze-Wei  Lei  Hang  Yang  Mao-Lin  Liao  Yong  Yu  Jia-Li 《计算机科学技术学报》2019,34(4):839-853

Coordinated partitioning and resource sharing have attracted considerable research interest in the field of real-time multiprocessor systems. However, finding an optimal partition is widely known as NP-hard, even for independent tasks. A recently proposed resource-oriented partitioned (ROP) fixed-priority scheduling that partitions tasks and shared resources respectively has been shown to achieve a non-trivial speedup factor guarantee, which promotes the research of coordinated scheduling to a new level. Despite the theoretical elegance, the schedulability performance of ROP scheduling is restricted by the heuristic partitioning methods used in the original study. In this paper, we address the partitioning problem for tasks and shared resources under the ROP scheduling. A unified schedulability analysis framework for the ROP scheduling is proposed in the first place. A sophisticated partitioning approach based on integer linear programming (ILP) is then proposed based on the unified analysis. Empirical results show that the proposed methods improve the schedulability of ROP scheduling significantly, and the runtime complexity for searching a solution is reduced prominently compared with other ILP-based approaches as well.

  相似文献   

6.
弱硬实时应用要求调度算法必须确保提供满足其弱硬实时QoS(Quality of Service)参数要求的服务,一种新的能够提供(m,k)-firm保证的固定优先级调度算法被提出,该算法能够根据任务的周期以及所要求的QoS参数进行调度优先级的设定,并通过将任务设置为抢占和可选来反映其紧迫程度。文中给出该算法的可调度判定不等式,并且通过对经典任务集的调度结果,验证了算法的有效性和灵活性。  相似文献   

7.
Scheduling a batch processing machine with incompatible job families   总被引:6,自引:0,他引:6  
The problem of scheduling batch processors is important in some industries and, at a more fundamental level, captures an element of complexity common to many practical scheduling problems. We describe a branch and bound procedure applicable to a batch processor model with incompatible job families. Jobs in a given family have identical job processing times, arbitrary job weights, and arbitrary job sizes. Batches are limited to jobs from the same family. The scheduling objective is to minimize total weighted completion time. We find that the procedure returns optimal solutions to problems of up to about 25 jobs in reasonable CPU time, and can be adapted for use as a heuristic for larger problems.  相似文献   

8.
T.  M.  C.  B.  K.  P.  E.   《Future Generation Computer Systems》2009,25(8):912-925
A key problem in Grid networks is how to efficiently manage the available infrastructure, in order to satisfy user requirements and maximize resource utilization. This is in large part influenced by the algorithms responsible for the routing of data and the scheduling of tasks. In this paper, we present several multi-cost algorithms for the joint scheduling of the communication and computation resources that will be used by a Grid task. We propose a multi-cost scheme of polynomial complexity that performs immediate reservations and selects the computation resource to execute the task and determines the path to route the input data. Furthermore, we introduce multi-cost algorithms that perform advance reservations and thus also find the starting times for the data transmission and the task execution. We initially present an optimal scheme of non-polynomial complexity and by appropriately pruning the set of candidate paths we also give a heuristic algorithm of polynomial complexity. Our performance results indicate that in a Grid network in which tasks are either CPU- or data-intensive (or both), it is beneficial for the scheduling algorithm to jointly consider the computational and communication problems. A comparison between immediate and advance reservation schemes shows the trade-offs with respect to task blocking probability, end-to-end delay and the complexity of the algorithms.  相似文献   

9.
We consider the problem of preemptively scheduling a set of periodic, real-time tasks on a multiprocessor computer system. We give a new scheduling algorithm, the so-called Slack-Time Algorithm, and show that it is more effective than the known Deadline Algorithm. We also give an (exponential-time) algorithm to decide if a task system is schedulable by the Slack-Time or the Deadline Algorithm. The same algorithm can also be used to decide if a task system is schedulable by any given fixed-priority scheduling algorithm. This resolves an open question posed by Leung and Whitehead. Finally, it is shown that the problem of deciding if a task system is schedulable by the Slack-Time, the Deadline, or any given fixed-priority scheduling algorithm is co-NP-hard for each fixedm.  相似文献   

10.
重点研究了固定优先级抢占调度(FPPS)下的条件保证预算(CGB)的可调度性.先引入占用时间和进度的概念,对于具有任意周期和相位的实时资源调度,基于最好情况时间以及最坏情况时间等基础分析技术将周期按照一定规则划分为不同区域并分别加以分析,详细阐述并推理得出计算系统中可以使用的CGB大小的算法.在系统资源可调度性上,提出的计算CGB的方法可以对资源进行更好地配置,提高了资源的有效利用率.  相似文献   

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