Fixed priority scheduling with limited priority levels

Katcher, Daniel I.; Sathaye, Shirish S.; Strosnider, J.K.

doi:10.1109/12.464392

Cited by 27 publications

(11 citation statements)

References 11 publications

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“…In contrast, only few researchers (Katcher et al 1995;Orozzo et al, 1998;Xuelian et al, 2003) have reported work on scheduling tasks with limited priority levels. Ketcher et al (1995) addressed the scheduling of a fixed priority system by restricting priority levels to a limited number.…”

Section: Background and Related Workmentioning

confidence: 99%

Maintaining the Feasibility of Hard Real–Time Systems with a Reduced Number of Priority Levels

Qureshi

Alrashed

Min‐Allah

et al. 2015

International Journal of Applied Mathematics and Computer Science

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When there is a mismatch between the cardinality of a periodic task set and the priority levels supported by the underlying hardware systems, multiple tasks are grouped into one class so as to maintain a specific level of confidence in their accuracy. However, such a transformation is achieved at the expense of the loss of schedulability of the original task set. We further investigate the aforementioned problem and report the following contributions: (i) a novel technique for mapping unlimited priority tasks into a reduced number of classes that do not violate the schedulability of the original task set and (ii) an efficient feasibility test that eliminates insufficient points during the feasibility analysis. The theoretical correctness of both contributions is checked through formal verifications. Moreover, the experimental results reveal the superiority of our work over the existing feasibility tests by reducing the number of scheduling points that are needed otherwise.

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Section: Background and Related Workmentioning

confidence: 99%

Maintaining the Feasibility of Hard Real–Time Systems with a Reduced Number of Priority Levels

Qureshi

Alrashed

Min‐Allah

et al. 2015

International Journal of Applied Mathematics and Computer Science

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“…As an example, consider the case study that is discussed in (Katcher 1995). A highspeed network connects one or more multimedia servers to multimedia workstations where traffic consists of a mixture of video, audio, voice, MIDI, and large file transfers in addition to periodic and aperiodic network management messages.…”

Section: Perts Front-endmentioning

confidence: 99%

“…Rather, it assumes that all tasks have equal execution time. The work presented in (Katcher 1995) develops both necessary and sufficient conditions for determining schedulability on a single node system with limited priorities. A metric called the degree of schedulable saturation is introduced to evaluate the impact of task groupings on schedulability.…”

Section: The Distributed Priority Ceiling Protocolmentioning

confidence: 99%

“…For instance, the schedulability analysis must account for blocking of higher global priority tasks by lower global priority tasks that is caused by the higher and lower global priority tasks being mapped to the same local priority, and thus being scheduled first-in-first-out (FIFO) by POSIX1c-based real-time operating systems. Some work on priority mapping has been done (Lehoczky 1986, Katcher 1995, and we review that work in Section 2. However, a priority mapping solution for enforcing global priorities in middleware that must interact with local real-time operating systems, has not been developed.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Scheduling and Priority Mapping for Static Real-Time Middleware

DiPippo¹,

Wolfe²,

Esibov³

et al. 2001

Challenges in Design and Implementation of Middlewares for Real-Time Systems

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Abstract. This paper presents a middleware real-time scheduling technique for static, distributed, real-time applications. The technique uses global deadline monotonic priority assignment to clients and the Distributed Priority Ceiling protocol to provide concurrency control and priorities for server execution. The paper presents a new algorithm for mapping the potentially large number of unique global priorities required by this scheduling technique to the restricted set of priorities provided by commercial real-time operating systems. This algorithm is called Lowest Overlap First Priority Mapping; we prove that it is optimal among direct priority mapping algorithms. This paper also presents the implementation of these real-time middleware scheduling techniques in a Scheduling Service that meets the interface proposed for such a service in the Real-Time CORBA 1.0 standard. Our prototype Scheduling Service is integrated with the commercial PERTS tool that provides schedulability analysis and automated generation of global and local priorities for clients and servers.

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“…, is addressed in [3]. They give an exponential time algorithm for determining the assignment that gives the smallest response time while ensuring that the system remains schedulable, if such an assignment exists.…”

Section: Related Workmentioning

confidence: 99%