| 1. |
- Brandenburg, Björn, et al.
(författare)
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Message from the Chairs : RTAS 2019
- 2019
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Ingår i: 2019 IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS). - 1545-3421. - 9781728106786 ; 2019-April
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Presents the introductory welcome message from the conference proceedings. May include the conference officers' congratulations to all involved with the conference event and publication of the proceedings record.
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| 2. |
- Imes, Connor, et al.
(författare)
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POET: A Portable Approach to Minimizing Energy Under Soft Real-time Constraints
- 2015
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Ingår i: Real-Time and Embedded Technology and Applications Symposium (RTAS), 2015 IEEE. - 1545-3421. - 9781479986033 - 9781479986040 ; , s. 75-86
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Konferensbidrag (refereegranskat)abstract
- Embedded real-time systems must meet timing constraints while minimizing energy consumption. To this end, many energy optimizations are introduced for specific platforms or specific applications. These solutions are not portable, however, and when the application or the platform change, these solutions must be redesigned. Portable techniques are hard to develop due to the varying tradeoffs experienced with different application/platform configurations. This paper addresses the problem of finding and exploiting general tradeoffs, using control theory and mathematical optimization to achieve energy minimization under soft real-time application constraints. The paper presents POET, an open-source C library and runtime system that takes a specification of the platform resources and optimizes the application execution. We test POET's ability to deliver portable energy reduction on two embedded systems with different tradeoff spaces - the first with a mobile Intel Haswell processor, and the second with an ARM big.LITTLE System on Chip. POET achieves the desired latency goals with small error while consuming, on average, only 1.3% more energy than the dynamic optimal oracle on the Haswell and 2.9% more on the ARM. We believe this open-source, library-based approach to resource management will simplify the process of writing portable, energy-efficient code for embedded systems.
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| 3. |
- Pathan, Risat, 1979
(författare)
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Unifying Fixed- and Dynamic-Priority Scheduling based on Priority Promotion and an Improved Ready Queue Management Technique
- 2015
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Ingår i: Proceedings of the IEEE Real-Time and Embedded Technology and Applications Symposium, RTAS. - 1545-3421. - 9781479986033 ; 2015-May:Art nr. 7108444, s. 209-220
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a new preemptive scheduling algorithm, called Fixed-Priority with Priority Promotion (FPP), for scheduling sporadic tasks on uni- and multiprocessor platform. In FPP scheduling, tasks are executed similar to traditional fixed-priority (FP) scheduling but the priority of some tasks may be promoted at fixed time interval (called, promotion point) relative to the release time of each job. A policy called Increase Priority at Deadline Difference (IPDD) to compute the promotion points and promoted priorities for each task is proposed. It is shown that when all tasks' priorities are governed under IPDD policy, then FPP scheduling essentially prioritizes jobs according to Earliest-Deadline-First (EDF) priority. It is known that inserting and removing jobs to and from the ready queue of traditional EDF scheduler is more complex and has higher overhead than that of FP scheduler. To avoid such problem in FPP scheduling, a simple data structure and efficient operations to insert and remove jobs to and from the ready queue are proposed. Finally, an effective scheme to reduce overhead due to priority promotion is proposed: if a task set is not schedulable using traditional FP scheduling, then promotion points are assigned only to those tasks that need them to meet the deadlines; otherwise, tasks are assigned fixed priorities without any priority promotion and executed same as traditional FP scheduling. Empirical investigation shows the effectiveness of the proposed scheme in reducing overhead on uniprocessor and in accepting larger number of task sets in comparison to that of using state-of-the-art global schedulability tests for multiprocessors. © 2015 IEEE.
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| 4. |
- Voudouris, Petros, 1987, et al.
(författare)
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Timing-anomaly free dynamic scheduling of task-based parallel applications
- 2016
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Ingår i: Proceedings of the IEEE Real-Time and Embedded Technology and Applications Symposium, (RTAS 2017). Pittsburgh, PA, APR 18-21, 2017. - 1545-3421. - 9781509052691 ; 0, s. 365-376
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Konferensbidrag (refereegranskat)abstract
- Multicore architectures can provide high predictable performance through parallel processing. Unfortunately, computing the makespan of parallel applications is overly pessimistic either due to load imbalance issues plaguing static scheduling methods or due to timing anomalies plaguing dynamic scheduling methods. This paper contributes with an anomaly-free dynamic scheduling method, called Lazy, which is non-preemptive and non-greedy in the sense that some ready tasks may not be dispatched for execution even if some processors are idle. Assuming parallel applications using contemporary taskbased parallel programming models, such as OpenMP, the general idea of Lazy is to avoid timing anomalies by assigning fixed priorities to the tasks and then dispatch selective highestpriority ready tasks for execution at each scheduling point. We formally prove that Lazy is timing-anomaly free. Unlike all the commonly-used dynamic schedulers like breadth-first and depth-first schedulers (e.g., CilkPlus) that rely on analytical approaches to determine an upper bound on the makespan of parallel application, a safe makespan of a parallel application is computed by simulating Lazy. Our experimental results show that the makespan computed by simulating Lazy is much tighter and scales better as demonstrated by four parallel benchmarks from a task-parallel benchmark suite in comparison to the state-of-the-art.
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| 5. |
- Voudouris, Petros, 1987, et al.
(författare)
-
Timing-anomaly free dynamic scheduling of task-based parallel applications
- 2017
-
Ingår i: Proceedings of the IEEE Real-Time and Embedded Technology and Applications Symposium, RTAS. - 1545-3421. ; , s. 365-376
-
Konferensbidrag (refereegranskat)abstract
- Multicore architectures can provide high predictable performance through parallel processing. Unfortunately, computing the makespan of parallel applications is overly pessimistic either due to load imbalance issues plaguing static scheduling methods or due to timing anomalies plaguing dynamic scheduling methods. This paper contributes with an anomaly-free dynamic scheduling method, called Lazy, which is non-preemptive and non-greedy in the sense that some ready tasks may not be dispatched for execution even if some processors are idle. Assuming parallel applications using contemporary taskbased parallel programming models, such as OpenMP, the general idea of Lazy is to avoid timing anomalies by assigning fixed priorities to the tasks and then dispatch selective highestpriority ready tasks for execution at each scheduling point. We formally prove that Lazy is timing-anomaly free. Unlike all the commonly-used dynamic schedulers like breadth-first and depth-first schedulers (e.g., CilkPlus) that rely on analytical approaches to determine an upper bound on the makespan of parallel application, a safe makespan of a parallel application is computed by simulating Lazy. Our experimental results show that the makespan computed by simulating Lazy is much tighter and scales better as demonstrated by four parallel benchmarks from a task-parallel benchmark suite in comparison to the state-of-the-art.
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