OpenMP and Timing Predictability: A Possible Union?

Proceedings of the 2016 Design, Automation &Amp; Test in Europe Conference &Amp; Exhibition (DATE)

Melani

Bertogna

et al. 2016

Self Cite

Abstract-Limited preemptive (LP) scheduling has been demonstrated to effectively improve the schedulability of fully preemptive (FP) and fully non-preemptive (FNP) paradigms. On one side, LP reduces the preemption related overheads of FP; on the other side, it restricts the blocking effects of FNP. However, LP has been applied to multi-core scenarios only when completely sequential task systems are considered. This paper extends the current state-of-the-art response time analysis for global fixed priority scheduling with fixed preemption points by deriving a new response time analysis for DAG-based task-sets.

Section: Related Workmentioning

confidence: 99%

Section: A Task Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Response-Time Analysis of DAG Tasks under Fixed Priority Scheduling with Limited Preemptions

Proceedings of the 2016 Design, Automation &Amp; Test in Europe Conference &Amp; Exhibition (DATE)

Melani

Bertogna

et al. 2016

Self Cite

“…Furthermore, recent studies demonstrate that the structure and syntax of the OpenMP tasking model resembles the Directed Acyclic Graph (DAG) scheduling real-time model [35]. This enables the analysis of the timing properties for such a model.…”

Section: Introductionmentioning

confidence: 99%

A Functional Safety OpenMP $$^{*}$$ for Critical Real-Time Embedded Systems

Royuela

Durán

Scaling OpenMP for Exascale Performance and Portability

et al. 2017

Abstract. OpenMP* has recently gained attention in the embedded domain by virtue of the augmentations implemented in the last specification. Yet, the language has a minimal impact in the embedded real-time domain mostly due to the lack of reliability and resiliency mechanisms. As a result, functional safety properties cannot be guaranteed. This paper analyses in detail the latest specification to determine whether and how the compliant OpenMP implementations can guarantee functional safety. Given the conclusions drawn from the analysis, the paper describes a set of modifications to the specification, and a set of requirements for compiler and runtime systems to qualify for safety critical environments. Through the proposed solution, OpenMP can be used in critical real-time embedded systems without compromising functional safety.

The Cooperative Parallel: A Discussion About Run-Time Schedulers for Nested Parallelism

Royuela

OpenMP: Conquering the Full Hardware Spectrum

García-Gasulla

et al. 2019

Nested parallelism is a well-known parallelization strategy to exploit irregular parallelism in HPC applications. This strategy also fits in critical real-time embedded systems, composed of a set of concurrent functionalities. In this case, nested parallelism can be used to further exploit the parallelism of each functionality. However, current run-time implementations of nested parallelism can produce inefficiencies and load imbalance. Moreover, in critical real-time embedded systems, it may lead to incorrect executions due to, for instance, a work non-conserving scheduler. In both cases, the reason is that the teams of OpenMP threads are a black-box for the scheduler, i.e., the scheduler that assigns OpenMP threads and tasks to the set of available computing resources is agnostic to the internal execution of each team. This paper proposes a new run-time scheduler that considers dynamic information of the OpenMP threads and tasks running within several concurrent teams, i.e., concurrent parallel regions. This information may include the existence of OpenMP threads waiting in a barrier and the priority of tasks ready to execute. By making the concurrent parallel regions to cooperate, the shared computing resources can be better controlled and a work conserving and priority driven scheduler can be guaranteed.