Implementing an Application-Defined Scheduling Framework for Ada Tasking

Aldea, Mario; Miranda, Javier; Harbour, Michael González

doi:10.1007/978-3-540-24841-5_23

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…Earliestdeadline-first dispatching enforces priority inversion avoidance through the Preemption-Level Protocol (PLP) [Burns et al 2004], which is a special version of the stack resource policy [Baker 1991]. It is worth noting that, during the process of defining the new Ada specification, a proposition was made for the endowment of Ada with application-defined scheduling capabilities [Aldea and Harbour 2003;Aldea et al 2004]. The approach is similar to the framework in this article with a major difference being that the proposed Ada framework presupposes the existence of application-defined facilities in the operating system, or the ability of the operating system to accept kernel-loadable modules.…”

Section: Real-time Programming Languagesmentioning

confidence: 99%

A framework for flexible scheduling in the RTSJ

Zerzelidis

Wellings

2010

ACM Trans. Embed. Comput. Syst.

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This article presents a viable solution to introducing flexible scheduling in the Real-Time specification for Java (RTSJ), in the form of a flexible scheduling framework. The framework allows the concurrent use of multiple application-defined scheduling policies, each scheduling a subset of the total set of threads. Moreover, all threads, regardless of the policy under which they are scheduled, are permitted to share common resources. Thus, the framework can accommodate a variety of interworking applications (soft, firm, and hard) running under the RTSJ. The proposed approach is a two-level scheduling framework, where the first level is the RTSJ priority scheduler and the second level is under application control. This article describes the framework's protocol, examines the different types of scheduling policies that can be supported, and evaluates the proposed framework by measuring its execution cost. A description of an application-defined Earliest-Deadline-First (EDF) scheduler illustrates how the interface can be used. Minimum backward-compatible changes to the RTSJ specification are discussed to motivate the required interface. The only assumptions made about the underlying real-time operating system is that it supports preemptive priority-based dispatching of threads and that changes to priorities have immediate effect.

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Section: Real-time Programming Languagesmentioning

confidence: 99%

A framework for flexible scheduling in the RTSJ

Zerzelidis

Wellings

2010

ACM Trans. Embed. Comput. Syst.

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“…We note that, from the different techniques and approaches enumerated so far in this section, global scheduling imposes implementation requirements that need to be either fulfilled by the underlaying real-time operating system, or implemented at user level by means of some kind of application-defined scheduler [1]. But the rest of approaches (task and job partitioning, and task splitting) can be implemented by using features that are being considered for inclusion in Ada 2012.…”

Section: Multiprocessor Requirementsmentioning

confidence: 99%

Adding multiprocessor and mode change support to the Ada real-time framework

2013

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Association for Computing Machinery (ACM)Sáez Barona, S.; Real Sáez, JV.; Crespo Lorente, A. (2013). Adding multiprocessor and mode change support to the Ada real-time framework. Ada Letters. 33 (1) AbstractBased on a previous proposal of an Ada 2005 framework of real-time utilities, this paper deals with the extension of that framework to include support for multiprocessor platforms and multiple operating modes and mode changes. The design of the proposed framework is also intended to be amenable to automatic code generation.

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Integrating Application-Defined Scheduling with the New Dispatching Policies for Ada Tasks

Rivas

Miranda

Harbour

2005

Reliable Software Technology – Ada-Europe 2005

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In previous papers we had presented an application program interface (API) that enabled applications to use application-defined scheduling algorithms for Ada tasks in a way compatible with the scheduling model defined in the realTime Annex of the language. Each application scheduler was implemented with a special task. This paper presents a new implementation in which the application scheduler actions are executed as part of the kernel on which the run-time system is based, thus increasing the efficiency. This paper also presents modifications to the proposed API that align it with the evolution of the Ada Issues being considered in the Ada 200Y standardization. First, we use the new concept of deadline as an abstract notion of urgency, to order the tasks in the scheduling queue of the underlying kernel, freeing the application scheduler of the responsibility of keeping the desired ordering of tasks, and thus simplifying it and reducing its overhead. In second place, we also consider task synchronization through protected objects using the new Stack Resource Policy proposed for the EDF task dispatching policy in Ada 200Y, which can be used in a large variety of fixed and dynamic priority scheduling policies without explicit intervention of the application scheduler.

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Implementing an Application-Defined Scheduling Framework for Ada Tasking

Cited by 4 publications

References 7 publications

A framework for flexible scheduling in the RTSJ

A framework for flexible scheduling in the RTSJ

Adding multiprocessor and mode change support to the Ada real-time framework

Integrating Application-Defined Scheduling with the New Dispatching Policies for Ada Tasks

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