An Isolation Scheduling Model for Multicores

Huang, Pengcheng; Giannopoulou, Georgia; Ahmed, Rehan; Bartolini, Davide B.; Thiele, Lothar

doi:10.1109/rtss.2015.21

Cited by 15 publications

(11 citation statements)

References 29 publications

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“…However, these prior real-time gang scheduling policies also allow co-scheduling of multiple gangs as long as there exist available cores because they mainly focus on CPU utilization, without considering the negative WCET impact of co-scheduling on shared memory multicore platforms. On the other hand, the Isolation Scheduling model [21] and the integrated modular avionic (IMA) scheduler design in [34] consider shared resource interference and limit coscheduling to the tasks of the same criticality (in [21]) or those in the same IMA partition (in [34]). However, they do not specifically target parallel real-time tasks and do not allow co-scheduling of best-effort tasks.…”

Section: Related Workmentioning

confidence: 99%

RT-Gang: Real-Time Gang Scheduling Framework for Safety-Critical Systems

Ali

Yun

2019

2019 IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS)

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In this paper, we present RT-Gang: a novel realtime gang scheduling framework that enforces a one-gang-at-atime policy. We find that, in a multicore platform, co-scheduling multiple parallel real-time tasks would require highly pessimistic worst-case execution time (WCET) and schedulability analysiseven when there are enough cores-due to contention in shared hardware resources such as cache and DRAM controller.In RT-Gang, all threads of a parallel real-time task form a real-time gang and the scheduler globally enforces the one-gangat-a-time scheduling policy to guarantee tight and accurate task WCET. To minimize under-utilization, we integrate a state-ofthe-art memory bandwidth throttling framework to allow safe execution of best-effort tasks. Specifically, any idle cores, if exist, are used to schedule best-effort tasks but their maximum memory bandwidth usages are strictly throttled to tightly bound interference to real-time gang tasks.We implement RT-Gang in the Linux kernel and evaluate it on two representative embedded multicore platforms using both synthetic and real-world DNN workloads. The results show that RT-Gang dramatically improves system predictability and the overhead is negligible.

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Section: Related Workmentioning

confidence: 99%

RT-Gang: Real-Time Gang Scheduling Framework for Safety-Critical Systems

Ali

Yun

2019

2019 IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS)

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“…To overcome this limitation, the authors of [25,13] propose scheduling MC applications such that only tasks of the same criticality can be executed, and hence interfere on shared platform resources, at any time. Huang et al formalise this notion under the term Isolation Scheduling and provide optimality results in [33]. In this paper, we employ policies for Isolation Scheduling of MC systems in order to facilitate their deployment on commercial-off-the-shelf platforms without dedicated hardware support.…”

Section: Related Workmentioning

confidence: 99%

DOL-BIP-Critical: a tool chain for rigorous design and implementation of mixed-criticality multi-core systems

Giannopoulou

Poplavko

Socci

et al. 2018

Des Autom Embed Syst

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Mixed-criticality systems are promoted in industry due to their potential to reduce size, weight, power, and cost. Nonetheless, deploying mixed-criticality applications on commercial multi-core platforms remains a highly challenging problem. To name a few reasons: (i) Industrial mixed-criticality applications are usually complex reactive applications, which cannot be specified by traditional, e.g., dataflow-based, models of computation. Appropriate mixed-criticality models of computation built upon Vestal's assumptions are missing; (ii) Scheduling such applications on multicores with shared resources, such as memory buses, requires that any timing interference among applications of different criticality is bounded in order to guarantee-the necessary for certification-temporal isolation and to enable incremental design; (iii) The implementation of isolation-preserving mixed-criticality schedulers is itself subject to certification. Hence, it needs to be not only efficient, but also provably correct. This paper proposes, for the first time, a complete design flow covering all aspects from specification, using a novel mixed-criticality aware model of computation (DOL-Critical), to correct-by-construction implementation, using the principle 'what you verify is what you generate' which is based on a novel variant of task automata (BIP). We demonstrate the applicability of our design flow with an industrial avionic test case on the state-of-the-art Kalray MPPA R-256. Keywords real-time systems • mixed-criticality systems • multi-core scheduling • rigorous design • software synthesis • avionics

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“…A third approach for bounding interference on mixed-criticality multi-core designs is Isolation Scheduling (IS) [13]. The key idea is, instead of fine-grained resource arbitration, to only permit tasks of the same criticality to execute concurrently.…”

Section: Related Workmentioning

confidence: 99%

“…The key idea is, instead of fine-grained resource arbitration, to only permit tasks of the same criticality to execute concurrently. This way, IS policies [4,11,13] avoid intercriticality interference, while exploiting parallelism. Adaptive temporal partitioning is a special IS case, where task preemptions and migrations are not permitted.…”

Section: Related Workmentioning

confidence: 99%

“…Our multi-core scheduling approach reduces the complexity of interference analysis by applying global temporal partitioning, i.e. by allowing only applications of the same criticality to utilize the platform resources at any time [4,11,13]. For efficient resource utilization, the schedule of the temporal partitions can be dynamically adapted at runtime to react to occasionally higher resource demand (from high-criticality applications).…”

Section: Introductionmentioning

confidence: 99%

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Implementation of Partitioned Mixed-Criticality Scheduling on a Multi-Core Platform

Trüb

Giannopoulou

Tretter

et al. 2017

ACM Trans. Embed. Comput. Syst.

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Recent industrial trends favor the adoption of multi-core architectures for mixed-criticality applications. Although several mixed-criticality multi-core scheduling approaches have been proposed, currently there are few implementations on hardware that demonstrate efficient resource utilization and the ability to bound interference on shared resources. To address this necessity, we develop a mixed-criticality runtime environment on the Kalray MPPA-256 Andey many-core platform. The runtime environment implements a scheduling policy based on adaptive temporal partitioning. We develop models, methods and implementation principles to implement the necessary scheduling primitives, to achieve high platform utilization and to perform a compositional worst-case execution time analysis. The bounds account for scheduling overheads and for the inter-task interference on the platform's shared memory. Using realistic benchmarks from avionics and signal processing, we validate the correctness and tightness of the bounds and demonstrate a high platform utilization. CCS Concepts: • Computer systems organization → Embedded software; Real-time operating systems; Real-time system architecture;

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An Isolation Scheduling Model for Multicores

Cited by 15 publications

References 29 publications

RT-Gang: Real-Time Gang Scheduling Framework for Safety-Critical Systems

RT-Gang: Real-Time Gang Scheduling Framework for Safety-Critical Systems

DOL-BIP-Critical: a tool chain for rigorous design and implementation of mixed-criticality multi-core systems

Implementation of Partitioned Mixed-Criticality Scheduling on a Multi-Core Platform

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