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Journal ArticleDOI

Co-Scheduling Persistent Periodic and Dynamic Aperiodic Real-Time Tasks on Reconfigurable Platforms

TL;DR: This work presents a co-scheduling framework for the combined execution of such periodic and aperiodic real-time tasks on fully and run-time partially reconfigurable platforms and reveals that the proposed scheduling strategies are able to achieve high resource utilization with low task rejection rates over various simulation scenarios.
Abstract: As task preemption/relocation with acceptably low overheads become a reality in today's reconfigurable FPGAs, they are starting to show bright prospects as platforms for executing performance critical task sets while allowing high resource utilization. Many performance sensitive real-time systems including those in automotive and avionics systems, chemical reactors, etc., often execute a set of persistent periodic safety critical control tasks along with dynamic event driven aperiodic tasks. This work presents a co-scheduling framework for the combined execution of such periodic and aperiodic real-time tasks on fully and run-time partially reconfigurable platforms. Specifically, we present an admission control strategy and preemptive scheduling methodology for dynamic aperiodic tasks in the presence of a set of persistent periodic tasks such that aperiodic task rejections may be minimized, thus resulting in high resource utilization. We used the 2D slotted area model where the floor of the FPGA is assumed to be statically equipartitioned into a set of tiles in which any arbitrary task may be feasibly mapped. The experimental results reveal that the proposed scheduling strategies are able to achieve high resource utilization with low task rejection rates over various simulation scenarios.
Citations
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Book
01 Jan 2000
TL;DR: The journal Real-Time Systems publishes papers, short papers and correspondence articles that concentrate on real-time computing principles and applications, including requirements engineering, specification and verification techniques, design methods and tools, programming languages, operating systems, scheduling algorithms, architecture, hardware and interfacing.
Abstract: From the Publisher: Real-Time Systems is both a valuable reference for professionals and an advanced text for Computer Science and Computer Engineering students. Real world real-time applications based on research and practice State-of-the-art algorithms and methods for validation Methods for end-to-end scheduling and resource management More than 100 illustrations to enhance understanding Comprehensive treatment of the technology known as RMA (rate-monotonic analysis) methods A supplemental Companion Website www.prenhall.com/liu

435 citations

Journal ArticleDOI
TL;DR: The proposed approach utilizes the energy harvesting techniques and the PowerControl algorithm to reduce the nonharvested consumed energy and provides the highest percentage of adding messages, with a lower average in response time and energy consumption.
Abstract: This paper deals with the medium between two reconfigurable sensor nodes characterized by radio interfaces that support multiple channels for exchanging real-time messages under energy constraints. These constraints are violated if the consumed energy in transmission is higher than the remaining quantity of energy. A reconfiguration, i.e., any addition or removal of tasks in devices and consequently of messages on the medium, can cause the violation of real-time or energy constraints at run time. To achieve a feasible scheduling in time (i.e., message deadlines will be respected) and energy (i.e., there is available energy) on the medium, we propose new dynamic solutions: Balance, Dilute, and a Combination of them to manage any addition or removal of messages. The proposed approach utilizes the energy harvesting techniques and the PowerControl algorithm to reduce the nonharvested consumed energy. The proposed strategies achieve significant improvement over existing methods and provide the highest percentage of adding messages, with a lower average in response time and energy consumption. They reach a percentage of success in adding the highest priority messages while meeting deadlines up to 85%.

19 citations


Cites background or methods from "Co-Scheduling Persistent Periodic a..."

  • ...2) in the case of multiple channels: a) the proposed strategies continue to exhibit similar behavior by achieving higher addition success rates than the other considered strategies (EHD, DMP, RTQS, DPSC_PR/DPSC_FR, and GlobalScheduler), and Combination always achieves the highest one....

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  • ...Note that this strategy uses RM for periodic messages scheduling while sending aperiodic ones in the available slack time; e) the average response time provided by the Combination strategy has decreased significantly after using two channels; then, it increased a bit as channels number increases, but still lower than what is provided by EDH, DPSC_PR/DPSC_FR, and GlobalScheduler, since these strategies are providing a long response time with alow message addition success rate, whereas Combination provides the highest message addition success rate with a short response time....

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  • ...With five channels, the message addition success rate achieved by Balance is around 70%, by Dilute around 40%, and by Combination around 85%; b) the message addition success rates achieved by the related strategies EDH, DMP, RTQS, DPSC_PR/DPSC_FR, and GlobalScheduler do not exceed 30%....

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  • ...6, where: 1) in case of one channel: a) the average energy consumption provided by DMP, Balance, Dilute, and Combination strategies are close to each other, whereas RTQS and GlobalScheduler provide the highest ones, and EDH and DPSC_PR/DPSC_FR provide the lowest one....

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  • ...4, where: 1) the messages addition success rate achieved by the proposed strategies Balance and Dilute is increased symmetrically, where it is 1% for both strategies with one channel, and 5% for Balance and 8% for Dilute with five channels; 2) the messages addition success rate achieved by the strat- egy DPSC_PR/DPSC_FR is increased symmetrically, where it goes up to 5% with one channel and around 24% with five channels; 3) the messages addition success rate achieved by the strat- egy GlobalScheduler is increased symmetrically, where it is around 6% with one channel, and around 24% with five channels....

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Proceedings ArticleDOI
01 Aug 2018
TL;DR: In this article, a reliability-driven mixed critical periodic task schedule generation against HTH attacks is focused, where reliability ensured execution of mixed critical aperiodic and sporadic tasks is considered.
Abstract: The property of dynamic partial reconfiguration of modern field programmable gate arrays (FPGAs) has made it feasible to execute various mixed critical tasks on the same platform. This requires partitioning the FPGA fabric into several virtual portions (VPs) and a scheduling methodology to determine which task is to be executed when and in which FPGA VP. Executing a task in an FPGA VP requires runtime configuring of the VP with a bitstream or a reconfigurable intellectual property, procured from a third party intellectual property (3PIP) vendor. Recent literature has exposed the presence of malicious elements like hardware trojan horses (HTHs) in such 3PIP bitstreams. Such HTH is particularly dangerous as these remain dormant during testing and initial stages of operation, but gets activated suddenly at runtime to jeopardize the basic security primitives of the system. Thus, reliability driven mixed critical tasks processing on FPGAs against HTH attacks is important. Firstly, reliability driven mixed critical periodic task schedule generation against HTH attacks is focused. Secondly, reliability ensured execution of mixed critical aperiodic and sporadic tasks in the generated periodic task schedule is considered. Experimentation is carried out with a variety of bitstreams and performance evaluation is performed via metrics like task success rate, task rejection rate and task preemption rate.

10 citations


Cites background from "Co-Scheduling Persistent Periodic a..."

  • ...Works exist which focus on task scheduling and execution on FPGAs without taking its vulnerability aspects into account [18]....

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  • ...Bitstreams with which the FPGA VPs are to be reconfigured at runtime are stored in the FPGA memory or resource pool [17], [18]....

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Journal ArticleDOI
TL;DR: Simulation results show that cluster base approach increases the number of tasks scheduled on a multiprocessor system, system utilization, and reduces response time, migration, and preemption overheads.
Abstract: Real‐time systems are nowadays extensively used in most time‐critical embedded applications. The existing multiprocessor real‐time scheduling algorithms are based on partitioned and global scheduling approaches. The partitioned‐based algorithms suffer poor utilization bound, load balancing, not compatible for an open system environment, and the global scheduling approach faces problems like high scheduling, migration overhead. Cluster scheduling represents a hybrid scheduling approach which consists of a set of processors as clusters and tasks scheduled to each processor of clusters using a global scheduling approach. The different cluster formation heuristics are investigated for homogenous clusters. The main objective of this article is to propose task utilization‐based cluster formation and harmonic period aware task allocation for a hierarchical real‐time system on a multiprocessor platform. Tasks with high utilization, cluster size tune to a smaller value to achieve high utilization. Tasks with low utilization, the size of cluster tune to larger to reduce migration and scheduling overheads. Experimentation performed on multiprocessor real‐time simulator with a different set of tasks, multiprocessor system, different tasks utilization, and cluster size. Simulation results show that cluster base approach increases the number of tasks scheduled on a multiprocessor system, system utilization, and reduces response time, migration, and preemption overheads.

6 citations

Journal ArticleDOI
TL;DR: This work initially explores how HTHs implanted by 3PIP vendors in the bitstreams may cause active attacks, and develops strategies to ensure reliability for processing of mixed critical tasks on reconfigurable hardware against HTH attacks.

6 citations

References
More filters
Journal ArticleDOI
TL;DR: The survey outlines fundamental results about multiprocessor real-time scheduling that hold independent of the scheduling algorithms employed, and provides a taxonomy of the different scheduling methods, and considers the various performance metrics that can be used for comparison purposes.
Abstract: This survey covers hard real-time scheduling algorithms and schedulability analysis techniques for homogeneous multiprocessor systems. It reviews the key results in this field from its origins in the late 1960s to the latest research published in late 2009. The survey outlines fundamental results about multiprocessor real-time scheduling that hold independent of the scheduling algorithms employed. It provides a taxonomy of the different scheduling methods, and considers the various performance metrics that can be used for comparison purposes. A detailed review is provided covering partitioned, global, and hybrid scheduling algorithms, approaches to resource sharing, and the latest results from empirical investigations. The survey identifies open issues, key research challenges, and likely productive research directions.

910 citations


"Co-Scheduling Persistent Periodic a..." refers background in this paper

  • ...The situation becomes worse as the number of processing elements in the system increases [17]....

    [...]

Book
01 Jan 2000
TL;DR: The journal Real-Time Systems publishes papers, short papers and correspondence articles that concentrate on real-time computing principles and applications, including requirements engineering, specification and verification techniques, design methods and tools, programming languages, operating systems, scheduling algorithms, architecture, hardware and interfacing.
Abstract: From the Publisher: Real-Time Systems is both a valuable reference for professionals and an advanced text for Computer Science and Computer Engineering students. Real world real-time applications based on research and practice State-of-the-art algorithms and methods for validation Methods for end-to-end scheduling and resource management More than 100 illustrations to enhance understanding Comprehensive treatment of the technology known as RMA (rate-monotonic analysis) methods A supplemental Companion Website www.prenhall.com/liu

435 citations


"Co-Scheduling Persistent Periodic a..." refers methods in this paper

  • ...They proposed EDF-Next Fit (EDF-NF), a variant of the EDF [22] algorithm which uses the concept of master processes (servers) to reserve area and execution time for tasks....

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  • ...The newly arrived task is accepted if such a feasible EDF schedule is actually realizable....

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  • ...The admission controller then attempts to generate an Earliest Deadline First (EDF) schedule considering all tasks in L....

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  • ...We used a deadline partitioning based fair scheduling approach in order to schedule persistent periodic tasks and an EDF like strategy for scheduling aperiodic tasks on the spare computational resources left after the allocation of the periodic tasks....

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  • ...Andersson et al. [32] proposed necessary and sufficient feasibility conditions to achieve low overhead exact admission control in EDF scheduled systems consisting of either, only aperiodic tasks, or a combination of persistent periodic tasks and dynamic aperiodic tasks....

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Proceedings ArticleDOI
06 Jul 2010
TL;DR: This paper develops a unifying theory with the DP- FAIR scheduling policy and examines how it overcomes problems faced by greedy scheduling algorithms, and presents a simple DP-FAIR scheduling algorithm, DP-WRAP, which serves as a least common ancestor to many recent algorithms.
Abstract: We consider the problem of optimal real-time scheduling of periodic and sporadic tasks for identical multiprocessors. A number of recent papers have used the notions of fluid scheduling and deadline partitioning to guarantee optimality and improve performance. In this paper, we develop a unifying theory with the DP-FAIR scheduling policy and examine how it overcomes problems faced by greedy scheduling algorithms. We then present a simple DP-FAIR scheduling algorithm, DP-WRAP, which serves as a least common ancestor to many recent algorithms. We also show how to extend DP-FAIR to the scheduling of sporadic tasks with arbitrary deadlines.

172 citations


"Co-Scheduling Persistent Periodic a..." refers methods in this paper

  • ...DPCS-PR partitions the task set into m disjoint subsets using a strategy similar to DP-Wrap [7] as follows: the tasks are allocated (one tile at a time) in any order starting from...

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  • ...based proportional fair scheduling methodology [7] devel-...

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  • ...After checking the necessary condition in Equation (2), DPCS-PR partitions the task set into m disjoint subsets using a strategy similar to DP-Wrap [7] as follows: the tasks are allocated (one tile at a time) in any order starting from the first tile V1, such that the combined sum of task shares along with the reconfiguration overheads in each such tile is less than the time-slice interval tslr....

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Proceedings ArticleDOI
05 Dec 1995
TL;DR: Algorithms for the joint scheduling of periodic and aperiodic tasks in statically scheduled distributed real-time systems with very high guarantee ratios for various load and deadline scenarios are presented.
Abstract: In this paper we present algorithms for the joint scheduling of periodic and aperiodic tasks in statically scheduled distributed real-time systems. Periodic tasks are precedence constrained, distributed, and communicating over the nodes of the systems. Both soft and hard aperiodic tasks are handled. After a static schedule has been created in a first step, the algorithms determine the amount and distribution of unused resources and leeway in it. These are then used to incorporate aperiodic tasks into the schedule by shifting the periodic tasks' execution, without violating their feasibility. Run-time mechanisms are simple and require only little memory. Processors and communication nodes can be utilized fully. The algorithm performs on optimal online guarantee algorithm for hard aperiodic tasks of O(N). An extensive simulation study exhibits very high guarantee ratios for various load and deadline scenarios, which underlines the efficiency of our method.

152 citations


"Co-Scheduling Persistent Periodic a..." refers methods in this paper

  • ...discussed a similar approach called Slot-Shifting, in [28]....

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Journal ArticleDOI
TL;DR: It is proved that the synthetic utilization bound for deadline-monotonic scheduling of aperiodic tasks is 1/1+/spl radic/1/2, and it is shown that no other time-independent scheduling policy can have a higher schedulability bound.
Abstract: Real-time scheduling theory offers constant-time schedulability tests for periodic and sporadic tasks based on utilization bounds. Unfortunately, the periodicity or the minimal interarrival-time assumptions underlying these bounds make them inapplicable to a vast range of aperiodic workloads such as those seen by network routers, Web servers, and event-driven systems. This paper makes several important contributions toward real-time scheduling theory and schedulability analysis. We derive the first known bound for schedulability of aperiodic tasks. The bound is based on a utilization-like metric we call synthetic utilization, which allows implementing constant-time schedulability tests at admission control time. We prove that the synthetic utilization bound for deadline-monotonic scheduling of aperiodic tasks is 1/1+/spl radic/1/2. We also show that no other time-independent scheduling policy can have a higher schedulability bound. Similarly, we show that EDF has a bound of 1 and that no dynamic-priority policy has a higher bound. We assess the performance of the derived bound and conclude that it is very efficient in hit-ratio maximization.

127 citations