Preemptively scheduling hard-real-time sporadic tasks on one processor

Baruah, Sanjoy; Mok, Aloysius K.; Rosier, Louis E.

doi:10.1109/real.1990.128746

Cited by 517 publications

(437 citation statements)

References 8 publications

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“…Ekberg and Yi [4] improved upon EDF-VD by enabling and calculating distinct scale factors for different H-tasks and using a more precise demand bound function (dbf) based schedulability test [7]. This improves performance.…”

Section: Overviewmentioning

confidence: 99%

“…The proposed approach (outlined in pseudocode as Algorithm 1), is divided into three offline stages, (i) task-to-server assignment, (ii) sizing servers ("inflating", in NPS-F jargon) and (iii) mapping servers to processors. The first stage assigns H-tasks to servers via First-Fit (FF) bin-packing, subject to an exact uniprocessor EDF schedulability test, from classic (criticalityoblivious) EDF theory [7] that uses the respective H-WCETs as input. The Ltasks are assigned to a different set of servers via First-Fit, using the same test, but using their L-WCETs as inputs.…”

Section: System Modelmentioning

confidence: 99%

“…Algorithm 2 presents the First-Fit bin-packing routine that assigns tasks to servers. The exact uniprocessor EDF schedulability test employed therein makes use of the demand bound function [7]. It is an abstraction of the computational requirements of the tasks.…”

Section: System Modelmentioning

confidence: 99%

See 2 more Smart Citations

Semi-partitioned Mixed-Criticality Scheduling

Awan

Bletsas

Souto

et al. 2017

Architecture of Computing Systems - ARCS 2017

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Scheduling isolation in mixed-criticality systems is challenging without sacrificing performance. In response, we propose a scheduling approach that combines server-based semi-partitioning and deadline scaling. Semipartitioning (whereby only some tasks migrate, in a carefully managed manner), hitherto used in single criticality systems, offers good performance with low overheads. Deadline-scaling selectivelyprioritizes high-criticality tasks in parts of the schedule to ensure theirdeadlines are met even in rares case of execution time overrun. Ournew algorithm NPS-F-MC brings semi-partitioning to mixed-criticalityscheduling and uses Ekberg and Yi 19s state-ofthe-art deadline scaling approach. It ensures scheduling isolation among different-criticality tasksand only allows low-criticality task migration. We also explore variantsthat disallow migration entirely or relax the isolation between differentcriticalities (SP-EKB) in order to evaluate the performance tradeoffs associated with more flexible or rigid safety and isolation requirements. Semi-partitioned mixed-criticality schedulingMuhammad Ali Awan * + , Konstantinos Bletsas * + , Pedro F. Souto ‡ * and Eduardo Tovar * + * CISTER/INESC-TEC Research Centre, Porto, Portugal + ISEP/IPP, Porto ‡ Faculty of Engineering, University of Porto Abstract. Scheduling isolation in mixed-criticality systems is challenging without sacrificing performance. In response, we propose a scheduling approach that combines server-based semi-partitioning and deadlinescaling. Semi-partitioning (whereby only some tasks migrate, in a carefully managed manner), hitherto used in single criticality systems, offers good performance with low overheads. Deadline-scaling selectively prioritise high-criticality tasks in parts of the schedule to ensure their deadlines are met even in rares case of execution time overrun. Our new algorithm NPS-F-MC brings semi-partitioning to mixed-criticality scheduling and uses Ekberg and Yi's state-of-the-art deadline scaling approach. It ensures scheduling isolation among different-criticality tasks and only allows low-criticality task migration. We also explore variants that disallow migration entirely or relax the isolation between different criticalities (SP-EKB) in order to evaluate the performance tradeoffs associated with more flexible or rigid safety and isolation requirements.

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Section: Overviewmentioning

confidence: 99%

Section: System Modelmentioning

confidence: 99%

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Semi-partitioned Mixed-Criticality Scheduling

Awan

Bletsas

Souto

et al. 2017

Architecture of Computing Systems - ARCS 2017

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“…We define W c (r k ) as the total amount of remaining work after time r k for jobs in I c . Because the upper bound in (8) assumes that all jobs (including J k ) run for their full worst-case execution times, (8) implies…”

Section: B2mentioning

confidence: 99%

Response Time Bounds for G-EDF without Intra-Task Precedence Constraints

Erickson

Anderson

2011

Lecture Notes in Computer Science

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Abstract. Prior work has provided bounds on the deadline tardiness that a set of sporadic real-time tasks may incur when scheduled using the global earliest-deadline-first (G-EDF) scheduling algorithm. Under the sporadic task model, it is necessary that no individual task overutilize a single processor and that the set of all tasks does not overutilize the set of all processors. In this work we generalize the task model by allowing jobs within a single task to run concurrently. In doing so we remove the requirement that no task overutilize a single processor. We also provide tardiness bounds that are better than those available with the standard sporadic task model.

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“…In this model, the exact time of a transmission request is unknown but a lower bound on the time between two consecutive transmission requests from the same message stream is known. This model is supported in processor scheduling [4] (where a message stream is called a task) and in wired communication channels [17]. Wireless communication is of increasing interest in the design of distributed real-time systems, and many scheduling algorithms and analysis techniques for wireless communication are available for periodic messages.…”

Section: Introductionmentioning

confidence: 99%

Static-Priority Scheduling of Sporadic Messages on a Wireless Channel

Andersson

Tovar

2006

Lecture Notes in Computer Science

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Consider the problem of scheduling sporadic messages with deadlines on a wireless channel. We propose a collision-free medium access control (MAC) protocol which implements static-priority scheduling and present a schedulability analysis technique for the protocol. The MAC protocol allows multiple masters and is fully distributed; it is an adaptation to a wireless channel of the dominance protocol used in the CAN bus. But unlike that protocol, our protocol does not require a node having the ability to receive an incoming bit from the channel while transmitting to the channel. Abstract. Consider the problem of scheduling sporadic messages with deadlines on a wireless channel. We propose a collision-free medium access control (MAC) protocol which implements static-priority scheduling and present a schedulability analysis technique for the protocol. The MAC protocol allows multiple masters and is fully distributed; it is an adaptation to a wireless channel of the dominance protocol used in the CAN bus. But unlike that protocol, our protocol does not require a node having the ability to receive an incoming bit from the channel while transmitting to the channel. Static-Priority Scheduling of Sporadic Messages on a Wireless Channel

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Preemptively scheduling hard-real-time sporadic tasks on one processor

Cited by 517 publications

References 8 publications

Semi-partitioned Mixed-Criticality Scheduling

Semi-partitioned Mixed-Criticality Scheduling

Response Time Bounds for G-EDF without Intra-Task Precedence Constraints

Static-Priority Scheduling of Sporadic Messages on a Wireless Channel

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