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PriorityDriven Scheduling of Periodic Task Systems on Multiprocessors
, 2001
"... The scheduling of systems of periodic tasks upon multiprocessor platforms is considered. ..."
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Cited by 117 (16 self)
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The scheduling of systems of periodic tasks upon multiprocessor platforms is considered.
Scheduling Periodic Task Systems to Minimize Output Jitter
, 1999
"... Output jitter  the variation in the intercompletion times of successive jobs of the same task  is studied in the context of the preemptive uniprocessor scheduling of periodic realtime tasks. A formal quantitative model for output jitter is proposed. A list of properties that are desirable ..."
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Cited by 59 (9 self)
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Output jitter  the variation in the intercompletion times of successive jobs of the same task  is studied in the context of the preemptive uniprocessor scheduling of periodic realtime tasks. A formal quantitative model for output jitter is proposed. A list of properties that are desirable in any jitterminimization schedule is enumerated. Algorithms are presented for generating suchschedules, and bounds proved for the maximum jitter in schedules generated by these algorithms. Keywords. Scheduling: uniprocessor, preemptive# periodic tasks# output jitter. 1 Introduction In many realtime control applications, periodic activities represent the major computational demand on the system. Such periodic activities typically arise from sensory data acquisition, lowlevel servoing, control loops, action planning, and system monitoring, which need to be cyclically executed at specific rates (derived from the application requirements). These periodic activities are often formally m...
A polynomialtime approximation scheme for feasibility analysis in staticpriority systems with arbitrary relative deadlines
 In Proceedings of the 13th International Conference on RealTime Systems
, 2005
"... Current feasibility tests for the staticpriority scheduling of periodic task systems run in pseudopolynomial time. We present a fully polynomialtime approximation scheme (FPTAS) for feasibility analysis in staticpriority systems where each task’s relative deadline is constrained to be at most it ..."
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Cited by 39 (10 self)
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Current feasibility tests for the staticpriority scheduling of periodic task systems run in pseudopolynomial time. We present a fully polynomialtime approximation scheme (FPTAS) for feasibility analysis in staticpriority systems where each task’s relative deadline is constrained to be at most its period. This test is an approximation with respect to the amount of processor capacity that must be “sacrificed ” for the test to become exact. We show that an arbitrary level of accuracy, ɛ, may be chosen for the approximation scheme, and present a runtime bound that is polynomial in terms of ɛ and the number of tasks, n. Keywords: Realtime scheduling; Uniprocessor systems; Staticpriority systems; Feasibility analysis; Approximation algorithms.
Fairness in Periodic RealTime Scheduling
, 1995
"... The issue of temporal fairness in periodic realtime scheduling is considered. It is argued that such fairness is often a desirable characteristic in realtime schedules. A concrete criterion for temporal fairness  pfairness  is described. The weightmonotonic scheduling algorithm, a static prio ..."
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Cited by 31 (3 self)
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The issue of temporal fairness in periodic realtime scheduling is considered. It is argued that such fairness is often a desirable characteristic in realtime schedules. A concrete criterion for temporal fairness  pfairness  is described. The weightmonotonic scheduling algorithm, a static priority scheduling algorithm for generating pfair schedules, is presented and proven correct. A feasibility test is presented which, if satisfied by a system of periodic tasks, ensures that the weightmonotonic scheduling algorithm will schedule the system in a pfair manner.
Resource sharing in edfscheduled systems: A closer look
 In Proceedings of the 27th IEEE RealTime Systems Symposium
, 2006
"... Resource sharing in prioritybased systems can give rise to priorityinversion and blocking, wherein a job’s execution is delayed because a lowerpriority job holds some resource that is needed for execution. The Stack Resource Policy (SRP) can be used to reduce such blocking in EDFscheduled syst ..."
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Cited by 16 (6 self)
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Resource sharing in prioritybased systems can give rise to priorityinversion and blocking, wherein a job’s execution is delayed because a lowerpriority job holds some resource that is needed for execution. The Stack Resource Policy (SRP) can be used to reduce such blocking in EDFscheduled systems. An efficient implementation of an algorithm is presented for determining whether systems scheduled in this manner are feasible. Some interesting properties of such systems are derived. The technique of reducing the duration of blocking by the replication of selected resources is explored: an algorithm is presented which determines the minimum amount of resource replication necessary to achieve specified blocking times.
Adaptive Dissemination of Data in TimeCritical Asymmetric Communication Environments
, 1999
"... The proliferation of new dataintensive applications in asymmetric communication environments has led to an increasing interest in the development of pushbased techniques, in which the information is broadcast to a large population of clients in order to achieve the most efficient use of the limite ..."
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Cited by 14 (0 self)
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The proliferation of new dataintensive applications in asymmetric communication environments has led to an increasing interest in the development of pushbased techniques, in which the information is broadcast to a large population of clients in order to achieve the most efficient use of the limited server and communication resources. It is important to note that quite often the data that is broadcast is timecritical in nature. Most of the related current research focuses on a pure pushbased approach (Broadcast Disks model), where the transmission of data is done without allowing explicit requests from the users. More recently, some bidirectional models incorporating a lowcapacity uplink channel have been proposed in order to increase the functionality of the Broadcast Disks model. However, the impact of integration of the uplink channel has been investigated using only static client profiles or ignoring the existence of timing constraints associated with data. None of the existing...
Robustness results concerning edf scheduling upon uniform multiprocessors
 IEEE Transactions on Computers
, 2003
"... ..."
Exact and Efficient Analysis of Schedulability in FixedPacket Networks: A Generic Approach
 Proc. of IEEE INFOCOM'97
, 1996
"... Emerging heterogeneous, multimedia network applications, such as video teleconferencing, require guarantees of timely and effective information delivery. In particular, it is important that the network does not commit to an additional service unless throughput and timeliness guarantees can be provid ..."
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Cited by 9 (4 self)
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Emerging heterogeneous, multimedia network applications, such as video teleconferencing, require guarantees of timely and effective information delivery. In particular, it is important that the network does not commit to an additional service unless throughput and timeliness guarantees can be provided for both the new and existing connections. However, as both hardware changes and applications diversify, the forms of traffic patterns and of guarantees are impossible to predict a priori. In this paper, we provide a general model of traffic flows, and a schedulability test for a set of such flows on a packetswitched virtualcircuit fixedpacket network, together with a set of rules designed to make evaluation of the schedulability conditions feasible and efficient. An experimental study is presented which demonstrates the usefulness of the proposed rules and offers recommendations for building actual networks. We also derive testing sets for some standard traffic models and discuss issue...
Approximate bandwidth allocation for compositional realtime systems
 In Proceedings of the 21st Euromicro Conference on RealTime Systems
, 2009
"... Allocation of bandwidth among components is a fundamental problem in compositional realtime systems. Stateoftheart algorithms for bandwidth allocation use either exponentialtime or pseudopolynomialtime techniques for exact allocation, or lineartime, utilizationbased techniques which may o ..."
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Cited by 9 (3 self)
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Allocation of bandwidth among components is a fundamental problem in compositional realtime systems. Stateoftheart algorithms for bandwidth allocation use either exponentialtime or pseudopolynomialtime techniques for exact allocation, or lineartime, utilizationbased techniques which may overprovision bandwidth. In this paper, we develop a fullypolynomialtime approximation scheme (FPTAS) for allocating bandwidth for sporadic task systems scheduled by earliestdeadline first (EDF) upon an ExplicitDeadline Periodic (EDP) resource. Our algorithm takes, as parameters, the task system and an accuracy parameter ε> 0, and returns a bandwidth which is guaranteed to be at most a factor (1+ ε) more than the optimal minimum bandwidth required to successfully schedule the task system. Furthermore, the algorithm has time complexity that is polynomial in the number of tasks and 1/ε. Via simulations over randomlygenerated task systems, we have observed a several orders of magnitude decrease in runtime and a small relative error when comparing our proposed algorithm with the exact algorithm, even for mediumsized values of ε (e.g., ε ≈.3). 1
RealTime Mutable Broadcast Disks
, 1997
"... There is an increased interest in using broadcast disks to support mobile access to realtime databases. However, previous work has only considered the design of realtime immutable broadcast disks, the contents of which do not change over time. This paper considers the design of programs for real ..."
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Cited by 6 (0 self)
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There is an increased interest in using broadcast disks to support mobile access to realtime databases. However, previous work has only considered the design of realtime immutable broadcast disks, the contents of which do not change over time. This paper considers the design of programs for realtime mutable broadcast disks  broadcast disks whose contents are occasionally updated. Recent schedulingtheoretic results relating to pinwheel scheduling and pfair scheduling are used to design algorithms for the efficient generation of realtime mutable broadcast disk programs.