| 8061. |
- Inam, Rafia, et al.
(författare)
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Hierarchical Scheduling Framework Implementation in FreeRTOS
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report presents the implementation of hierarchical scheduling framework HSF on an open source real-time operating system FreeRTOS to support the temporal isolation of a number of real-time components (or applications) onto a single processor. The goal is to achieve predictable integration and reusability of independently developed components or tasks. It presents the initial results of the HSF implementation by running it on an AVR 32-bit board EVK1100. It addresses the fixed-priority preemptive scheduling at both global and local scheduling levels. It describes the detailed design of HSF with the emphasis of doing minimal changes to the underlying FreeRTOS kernel and keeping its API intact. Finally it provides (and compares) the results for the performance measures of periodic and deferrable servers with respect to the overhead of the implementation. Index Terms: real-time systems; hierarchical scheduling framework; fixed-priority scheduling
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| 8062. |
- Inam, Rafia, 1974-, et al.
(författare)
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Implementing and Evaluating Communication- Strategies in the ProCom Component Technology
- 2012
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Ingår i: Acm Sigbed Review. - 1551-3688. ; 9:4, s. 1-4
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents two strategies to support communication between real-time executable Runnable Virtual Node (RVN) components in the ProCom component technology. We describe the currently implemented server-based communication strategy which uses a dedicated server for communication. We compare the server-based technique with a direct (RVN-to-RVN) communication strategy. The paper also describes how these strategies could be evaluated for real-time performance, and the real-time analysis technologies needed to perform such an evaluation.
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| 8063. |
- Inam, Rafia, 1974-, et al.
(författare)
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Implementing Hierarchical Scheduling to support Multi-Mode System
- 2012
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Ingår i: 7th IEEE International Symposium on Industrial Embedded Systems (SIES) June 20 – June 22, 2012 Karlsruhe, Germany, Conference Proceedings. - Karlsruhe, Germany. ; , s. 319-322
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Konferensbidrag (refereegranskat)abstract
- Multi-mode embedded real-time systems exhibit a specific behavior for each mode and upon a mode-change request, the task-set and timing interfaces of the system need to be changed. Hierarchical Scheduling Framework (HSF) is a known technique to partition the CPU time into a number of hierarchically divided subsystems each consists of its own task set. We propose to implement a multi-mode system using a two-level HSF and provide a skeleton (framework) for an adaptive HSFs supporting multi-modes. Upon a mode-change request, the timing interface of each subsystem is changed, thus making the hierarchical scheduling adaptive in nature. We address the main goals for the implementation and describe the initial design details of Multi-Mode Adaptive Hierarchical Scheduling Framework (MMAHSF) with the emphasis of doing minimal changes to the underlying kernel.
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| 8064. |
- Inam, Rafia, et al.
(författare)
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Mode-Change Mechanisms support for Hierarchical FreeRTOS Implementation
- 2013
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Konferensbidrag (refereegranskat)abstract
- Multi-mode embedded real-time systems exhibit a specific behaviour for each mode, and upon a mode-change request the task-set and timing interfaces of the system need to be changed. This paper presents the implementation of a Multi- Mode Adaptive Hierarchical Scheduling Framework (MMAHSF) and provides a generic skeleton (framework) for a two-level adaptive hierarchical scheduling supporting multiple modes and multiple mode-change mechanisms on an open source real-time operating system (FreeRTOS). The MMAHSF enable applicationspecific implementations of mode-change protocols using a set of predefined mode-change mechanisms. The paper addresses different mode-change mechanisms at both global and local scheduling levels. It presents examples of mode-change protocols that are developed by composing together these mechanisms in multiple ways and provide the initial results of executing these protocols in the MMAHSF implementation on an AVR 32-bit board EVK1100.
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| 8065. |
- Inam, Rafia
(författare)
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Performance Preservation using Servers for Predictable Execution and Integration
- 2014
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Ingår i: The 38th Annual International Computers, Software & Applications Conference COMPSAC 2014. - 9781479935741 ; , s. 614-617
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Konferensbidrag (refereegranskat)abstract
- In real-time embedded systems the components and components integration must satisfy both functional correctness and extra-functional correctness, such as satisfying timing properties. Deploying multiple real-time components on a physical node poses timing problems in components’s integration. These timing problems during integration further effect predictability and reusability of real-time components. We propose a novel concept of runnable virtual node (RVN) whose interaction with the environment is bounded both by a functional and a temporal interface, and the validity of its internal temporal behaviour is preserved when integrated with other components or when reused in a new environment. Our realization of RVN exploits the latest techniques for hierarchical scheduling framework to achieve temporal isolation, and the principles from component-based software-engineering to achieve functional isolation. Proof-of-concept case studies executed on an AVR based 32- bit micro-controller demonstrates the preserving of real-time properties within components for predictable integration and reusability in a new environment without altering its temporal behaviour in both hierarchical scheduling and RVN contexts. We also take a step ahead towards expanding the performance preserving servers’ concept for multicore platform on which the scheduling of real-time tasks is inherently unpredictable due to the contention for shared physical memory and caches. It results in proposing and implementation of a novel type of server, called Multi-Resource Server (MRS) which controls the access to both CPU and memory bandwidth resources such that the execution of real-time tasks become predictable. The MRS provides temporal isolation both between tasks running on the same core, as well as, between tasks running on different cores. Further, we provide the schedulability analysis for MRS to provide predictable performance when composing multiple components on a shared multi-core platform.
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| 8066. |
- Inam, Rafia, et al.
(författare)
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Predictable integration and reuse of executable real-time components
- 2014
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Ingår i: Journal of Systems and Software. - : Elsevier BV. - 0164-1212 .- 1873-1228. ; 91, s. 147-162
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Tidskriftsartikel (refereegranskat)abstract
- We present the concept of runnable virtual node (RVN) as a means to achieve predictable integration and reuse of executable real-time components in embedded systems. A runnable virtual node is a coarse-grained software component that provides functional and temporal isolation with respect to its environment. Its interaction with the environment is bounded both by a functional and a temporal interface, and the validity of its internal temporal behaviour is preserved when integrated with other components or when reused in a new environment. Our realization of RVN exploits the latest techniques for hierarchical scheduling to achieve temporal isolation, and the principles from component-based software-engineering to achieve functional isolation. It uses a two-level deployment process, i.e. deploying functional entities to RVNs and then deploying RVNs to physical nodes, and thus also gives development benefits with respect to composability, system integration, testing, and validation. In addition, we have implemented a server-based inter-RVN communication strategy to not only support the predictable integration and reuse properties of RVNs by keeping the communication code in a separate server, but also increasing the maintainability and flexibility to change the communication code without affecting the timing properties of RVNs. We have applied our approach to a case study, implemented in the ProCom component technology executing on top of a FreeRTOS-based hierarchical scheduling framework and present the results as a proof-of-concept.
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| 8067. |
- Inam, Rafia, 1974-, et al.
(författare)
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Real-Time Component Integration using Runnable Virtual Nodes
- 2012
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Ingår i: Proceedings - 38th EUROMICRO Conference on Software Engineering and Advanced Applications, SEAA 2012. - 9780769547909 ; , s. 80-84
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Konferensbidrag (refereegranskat)abstract
- We present the concept of runnable virtual nodes (RVNs) as means to achieve predictable integration and temporal error-containment of real-time software components. An RVN exploits the latest techniques for hierarchical scheduling and is intended as a coarse-grained component for single-node deployment, that provides functional and temporal isolations with respect to its environment. It uses a two-level deployment process; i.e. deploying functional entities to RVNs and then deploying RVNs to physical nodes. The two-level deployment process not only gives development benefits with respect to composability, system integration, testing, validation and certification but also leverages the hierarchical scheduling to preserve the validity of an RVN's internal temporal behaviour when integrated with other components. We have applied our approach to a simple case study, implemented in the ProCom component-technology executing on top of FreeRTOS-based hierarchical scheduling and present our initial results as a proof-of-concept.
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| 8068. |
- Inam, Rafia, 1974-, et al.
(författare)
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Run-Time Component Integration and Reuse in Cyber-Physical Systems
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We present the concept of runnable virtual nodes as a means to achieve predictable integration and reuse of software components in cyber-physical systems. A runnable virtual nodeis a coarse-grained real-time component that provides functional and temporal isolation with respect to its environment.Its interaction with the environment is bounded both by a functional and a temporal interface, and the validity of itsinternal temporal behavior is preserved when integrated with other components or when reused in a new environment.Our realization of runnable virtual nodes exploits the latest techniques for hierarchical scheduling to achieve temporalisolation, and the principles from component-based software-engineering to achieve functional isolation. In the paperwe present a proof-of-concept case study, implemented in the ProCom component-technology executing on top of FreeRTOSbased hierarchical scheduling framework.
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| 8069. |
- Inam, Rafia, 1974-, et al.
(författare)
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Support for Hierarchical Scheduling in FreeRTOS
- 2011
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Ingår i: 2011 IEEE 16TH CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA). - : IEEE conference proceedings. - 9781457700187 ; , s. 1-10
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the implementation of a HierarchicalScheduling Framework (HSF) on an open sourcereal-time operating system (FreeRTOS) to support the temporalisolation between a number of applications, on a single processor.The goal is to achieve predictable integration and reusability ofindependently developed components or applications. We presentthe initial results of the HSF implementation by running it onan AVR 32-bit board EVK1100.The paper addresses the fixed-priority preemptive schedulingat both global and local scheduling levels. It describes the detaileddesign of HSF with the emphasis of doing minimal changes tothe underlying FreeRTOS kernel and keeping its API intact.Finally it provides (and compares) the results for the performancemeasures of idling and deferrable servers with respect to theoverhead of the implementation.
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| 8070. |
- Inam, Rafia, 1974-, et al.
(författare)
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Support for Legacy Real-Time Applications in an HSF-Enabled FreeRTOS - a technical report
- 2014
-
Rapport (refereegranskat)abstract
- This paper presents a runtime support to consolidate legacy together with other real-time applications, running a single instance of a real-time operating system (RTOS), and sharing system resources. In this context, we resort to the hierarchical scheduling framework (HSF) to provide tem- poral partitions for dierent applications, supporting their independent development and real-time analysis, thus resulting on a predictable inte- gration. In particular, the paper focuses on a constructive element, the legacy server that allows executing code that is unaware of the temporal partition within which it is deployed. Furthermore, we discuss the chal- lenges that need to be addressed to execute a legacy application in an HSF without modications to the original code. We focus on the chal- lenge of enabling sharing system resources, both hardware and software, as typically found in most industrial software systems. We propose a novel solution based on wrappers for the required RTOS system calls. We implement our ideas in a concrete implementation on FreeRTOS OS, taking advantage of a prior HSF implementation. The validation is performed by a proof-of-concept case study that shows a successful integration of a legacy application that uses shared resources in a system that executes other applications.
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