Multiprocessor Feasibility Analysis of Recurrent Task Systems with Specified Processor Affinities

Baruah, Sanjoy; Brandenburg, Björn B.

doi:10.1109/rtss.2013.24

Cited by 11 publications

(21 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The exact taskset generation parameters for an experiment are described along with the respective experiment. We assume implicit deadlines in our experiment because (i) the only available feasibility test for APA scheduling (Baruah and Brandenburg, 2013) applies only to implicit-deadline tasks; (ii) when assessing the scalability of the reduction-based methods, the choice of constrained or implicit deadlines is irrelevant; and (iii) tasksets with constrained deadlines are more difficult to schedule and hence would require more involved affinity assignment heuristics, which are not the focus of this work.…”

Section: Methodsmentioning

confidence: 99%

“…Scheduling on unrelated heterogenous multiprocessors APA scheduling could also be understood as global scheduling on a (degenerate) unrelated heterogeneous multiprocessor (e.g., see Funk, 2004), where each task has the same, constant execution cost on any processor included in its processor affinity, and "infinite" execution cost on any other processor. While such platforms have primarily been studied in the context of partitioned scheduling to date (e.g., Funk, 2004;Baruah, 2004;Andersson et al, 2010), Baruah and Brandenburg (2013) recently used this connection to derive feasibility tests for APA scheduling with implicit deadlines.…”

Section: Prior Work and Related Scheduling Problemsmentioning

confidence: 99%

“…Feasibility test for JLDP APA scheduling Baruah and Brandenburg (2013) recently proposed a feasibility test based on the connection between APA scheduling and scheduling on unrelated heterogenous multiprocessors. The test assumes implicit deadlines and also employs linear programming.…”

Section: Lp-based Schedulability Analysismentioning

confidence: 99%

See 2 more Smart Citations

Multiprocessor real-time scheduling with arbitrary processor affinities: from practice to theory

2014

View full text Add to dashboard Cite

Contemporary multiprocessor real-time operating systems, such as VxWorks, LynxOS, QNX, and real-time variants of Linux, allow a process to have an arbitrary processor affinity, that is, a process may be pinned to an arbitrary subset of the processors in the system. Placing such a hard constraint on process migrations can help to improve cache performance of specific multi-threaded applications, achieve isolation among applications, and aid in loadbalancing. However, to date, the lack of schedulability analysis for such systems prevents the use of arbitrary processor affinities in predictable hard real-time systems. This paper presents the first analysis of multiprocessor scheduling with arbitrary processor affinities from a real-time perspective. It is shown that job-level fixed-priority scheduling with arbitrary processor affinities is strictly more general than global, clustered, and partitioned job-level fixed-priority scheduling combined. Concerning the more general case of joblevel dynamic priorities, it is shown that global and clustered scheduling are equivalent to multiprocessor real-time scheduling with arbitrary processor affinities. The Linux push and pull scheduler is studied as a reference implementation and two approaches for the schedulability analysis of hard real-time tasks with arbitrary processor affinity masks are presented. In the first approach, the scheduling problem is reduced to "global-like" sub-problems to which existing global schedulability tests can be applied. The second approach is specifically based on response-time analysis and models the response-time computation as a linear optimization problem. The latter linear-programming-based approach has better runtime complexity than the former reduction-based approach. Schedulability experiments show the proposed techniques to be effective. This paper is an extended version of a prior ECRTS 2013 paper. The extensions and new contributions are summarized in Section 1.1.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Prior Work and Related Scheduling Problemsmentioning

confidence: 99%

See 1 more Smart Citation

Multiprocessor real-time scheduling with arbitrary processor affinities: from practice to theory

2014

View full text Add to dashboard Cite

show abstract

“…More recently, the problem of scheduling real-time workloads with arbitrary processor affinities (APAs) has been considered [5,15,23,24]. To avoid schedulability losses due to overly simple implementations of such processor affinities, two notions of scheduling with arbitrary processor affinities, weak and strong APA scheduling, have been identified in prior work [15].…”

Section: Introductionmentioning

confidence: 99%

“…A simple but important observation is that APA and HPA scheduling simultaneously generalize global, clustered, and partitioned scheduling, since they allow to confine each task's migrations to a specified set of processors. An APA/HPA taskset can thus be modeled as a global, clustered, or partitioned taskset with an appropriate processor affinity assignment [5,15,23,24].…”

Section: Introductionmentioning

confidence: 99%

Multiprocessor Real-Time Scheduling with Hierarchical Processor Affinities

Bonifaci

Brandenburg

D’Angelo

et al. 2016

2016 28th Euromicro Conference on Real-Time Systems (ECRTS)

Self Cite

View full text Add to dashboard Cite

Many multiprocessor real-time operating systems offer the possibility to restrict the migrations of any task to a specified subset of processors by setting affinity masks. A notion of &x0022;strong arbitrary processor affinity scheduling&x0022; (strong APA scheduling) has been proposed, this notion avoids schedulability losses due to overly simple implementations of processor affinities. Due to potential overheads, strong APA has not been implemented so far in a real-time operating system. We show that, in the special but highly relevant case of hierarchical processor affinities (HPA), strong APA scheduling can be implemented with a vastly improved runtime complexity. In particular, we present a strong HPA scheduler with a runtime complexity of O(m) per task arrival and O(log n + m2) per task departure, where m is the number of processors and n is the number of tasks, thus improving on the previous bounds of O(m2) and O(m n). The improved runtime algorithms allowed us to implement support for strong hierarchical processor affinities in LITMUS^RT. We benchmarked this implementation on a 24-core platform and observed non-negligible, but still viable runtime overheads. Additionally, in the case of a bilevel affinity hierarchy and when job priorities are based on deadlines, we argue that the performance of our strong HPA scheduler, HPA-EDF, can be related to system optimality in the following way: any collection of jobs that is schedulable (under any policy) on m unit-speed processors subject to hierarchical affinity constraints is correctly scheduled by HPA-EDF on m processors of speed 2.415. © 2016 IEEE

show abstract

Correspondence article: a correction of the reduction-based schedulability analysis for APA scheduling

2018

View full text Add to dashboard Cite

Multiprocessor Feasibility Analysis of Recurrent Task Systems with Specified Processor Affinities

Cited by 11 publications

References 10 publications

Multiprocessor real-time scheduling with arbitrary processor affinities: from practice to theory

Multiprocessor real-time scheduling with arbitrary processor affinities: from practice to theory

Multiprocessor Real-Time Scheduling with Hierarchical Processor Affinities

Correspondence article: a correction of the reduction-based schedulability analysis for APA scheduling

Contact Info

Product

Resources

About