As Moore's law comes to an end, multi-processor (MP) systems are becoming increasingly important in embedded systems design, hence real-time schedulability analysis for MP systems has become an important research topic. In this paper, we present an exact method for schedulability analysis of global multiprocessor scheduling with either fixed-priority (FP) or earliest-deadline-first (EDF) algorithms using the model-checker NuSMV. Compared to safe but pessimistic schedulability tests based on processor utilization bounds, model-checking can provide an exact answer to the schedulability of a taskset, as well as quantitative information on each task's best-case and worst- case response times.
{"title":"Schedulability Analysis of Global Fixed-Priority or EDF Multiprocessor Scheduling with Symbolic Model-Checking","authors":"Nan Guan, Z. Gu, Mingsong Lv, Qingxu Deng, Ge Yu","doi":"10.1109/ISORC.2008.74","DOIUrl":"https://doi.org/10.1109/ISORC.2008.74","url":null,"abstract":"As Moore's law comes to an end, multi-processor (MP) systems are becoming increasingly important in embedded systems design, hence real-time schedulability analysis for MP systems has become an important research topic. In this paper, we present an exact method for schedulability analysis of global multiprocessor scheduling with either fixed-priority (FP) or earliest-deadline-first (EDF) algorithms using the model-checker NuSMV. Compared to safe but pessimistic schedulability tests based on processor utilization bounds, model-checking can provide an exact answer to the schedulability of a taskset, as well as quantitative information on each task's best-case and worst- case response times.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114504172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. D. Miguel, Philippe Massonet, Juan Pedro Silva, Javier Fernández Briones
Modelling languages and development frameworks give support for functional and structural description of software architectures. But quality-aware applications require languages which allow expressing QoS as a first-class concept during architecture design and service composition, and to extend existing tools and infrastructures adding support for modelling, evaluating, managing and monitoring QoS aspects. In addition to its functional behaviour and internal structure, the developer of each service must consider the fulfilment of its quality requirements. If the service is flexible, the output quality depends both on input quality and available resources (e.g., amounts of CPU execution time and memory). From the software engineering point of view, modelling of quality-aware requirements and architectures require modelling support for the description of quality concepts, support for the analysis of quality properties (e.g. model checking and consistencies of quality constraints, assembly of quality), tool support for the transition from quality requirements to quality-aware architectures, and from quality-aware architecture to service run-time infrastructures. Quality management in run-time service infrastructures must give support for handling quality concepts dynamically. QoS-aware modeling frameworks and QoS-aware runtime management infrastructures require a common evolution to get their integration.
{"title":"Model Based Development of Quality-Aware Software Services","authors":"M. D. Miguel, Philippe Massonet, Juan Pedro Silva, Javier Fernández Briones","doi":"10.1109/ISORC.2008.23","DOIUrl":"https://doi.org/10.1109/ISORC.2008.23","url":null,"abstract":"Modelling languages and development frameworks give support for functional and structural description of software architectures. But quality-aware applications require languages which allow expressing QoS as a first-class concept during architecture design and service composition, and to extend existing tools and infrastructures adding support for modelling, evaluating, managing and monitoring QoS aspects. In addition to its functional behaviour and internal structure, the developer of each service must consider the fulfilment of its quality requirements. If the service is flexible, the output quality depends both on input quality and available resources (e.g., amounts of CPU execution time and memory). From the software engineering point of view, modelling of quality-aware requirements and architectures require modelling support for the description of quality concepts, support for the analysis of quality properties (e.g. model checking and consistencies of quality constraints, assembly of quality), tool support for the transition from quality requirements to quality-aware architectures, and from quality-aware architecture to service run-time infrastructures. Quality management in run-time service infrastructures must give support for handling quality concepts dynamically. QoS-aware modeling frameworks and QoS-aware runtime management infrastructures require a common evolution to get their integration.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124037924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We propose an incremental compaction algorithm. Our compactor selects a continuous area of the heap and evacuates it by incrementally copying all objects in the area to the rest of the heap. After all objects have been copied, our compactor incrementally updates pointers pointing into the evacuated area. During these processes, each original object and its copy are kept consistent. We implemented the compactor together with a snapshot garbage collector in the KVM. Our measurements show that (1) the largest free chunk is almost always more than 20% as large as the entire heap when the heap is twice as large as the maximum amount of live objects, (2) the runtime overhead is less than 20%, and (3) the maximum pause time caused by the compactor is comparable to that caused by the snapshot collector.
{"title":"Replication-Based Incremental Compaction","authors":"Tomoharu Ugawa, M. Yasugi, T. Yuasa","doi":"10.1109/ISORC.2008.61","DOIUrl":"https://doi.org/10.1109/ISORC.2008.61","url":null,"abstract":"We propose an incremental compaction algorithm. Our compactor selects a continuous area of the heap and evacuates it by incrementally copying all objects in the area to the rest of the heap. After all objects have been copied, our compactor incrementally updates pointers pointing into the evacuated area. During these processes, each original object and its copy are kept consistent. We implemented the compactor together with a snapshot garbage collector in the KVM. Our measurements show that (1) the largest free chunk is almost always more than 20% as large as the entire heap when the heap is twice as large as the maximum amount of live objects, (2) the runtime overhead is less than 20%, and (3) the maximum pause time caused by the compactor is comparable to that caused by the snapshot collector.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"14 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116580023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Estévez-Ayres, M. García-Valls, L. Almeida, P. Basanta-Val
Recently, the application domains where the development of systems with temporal guarantees is needed have increased. The majority of such domains are dynamic environments where the classical design approach is no longer applicable since it is too pessimistic. Thus, new challenges arise to adapt the current methodologies used in different architectural levels to these new environments. New directions and paradigms are needed to allow combining functional flexibility and dynamism with temporal predictability. The current work addresses these new challenges through the exploration of the applicability of concepts from the service oriented paradigm to distributed real-time systems. We propose a concrete system model based on a holistic time-triggered-based approach for design and configuration. Based on this model, we analyse the architectural entities required for two different architectural design approaches: static, when no reconfigurations at run-time are admitted, and dynamic, when these reconfigurations are possible. An exhaustive composition algorithm is also proposed.
{"title":"Solutions for Supporting Composition of Service-Based Real-Time Applications","authors":"I. Estévez-Ayres, M. García-Valls, L. Almeida, P. Basanta-Val","doi":"10.1109/ISORC.2008.21","DOIUrl":"https://doi.org/10.1109/ISORC.2008.21","url":null,"abstract":"Recently, the application domains where the development of systems with temporal guarantees is needed have increased. The majority of such domains are dynamic environments where the classical design approach is no longer applicable since it is too pessimistic. Thus, new challenges arise to adapt the current methodologies used in different architectural levels to these new environments. New directions and paradigms are needed to allow combining functional flexibility and dynamism with temporal predictability. The current work addresses these new challenges through the exploration of the applicability of concepts from the service oriented paradigm to distributed real-time systems. We propose a concrete system model based on a holistic time-triggered-based approach for design and configuration. Based on this model, we analyse the architectural entities required for two different architectural design approaches: static, when no reconfigurations at run-time are admitted, and dynamic, when these reconfigurations are possible. An exhaustive composition algorithm is also proposed.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126727658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optimal real-time scheduling is effective to not only schedulability improvement but also energy efficiency for real-time systems. In this paper, we propose real-time static voltage and frequency scaling (RT-SVFS) techniques based on an optimal real-time scheduling algorithm for multiprocessors. The techniques are theoretically optimal when the voltage and frequency can be controlled both uniformly and independently among processors. Simulation results show that the independent RT-SVFS technique closely approaches the lower bound on energy consumption if the voltage and frequency can be controlled minutely.
{"title":"Energy-Efficient Optimal Real-Time Scheduling on Multiprocessors","authors":"Kenji Funaoka, S. Kato, N. Yamasaki","doi":"10.1109/ISORC.2008.19","DOIUrl":"https://doi.org/10.1109/ISORC.2008.19","url":null,"abstract":"Optimal real-time scheduling is effective to not only schedulability improvement but also energy efficiency for real-time systems. In this paper, we propose real-time static voltage and frequency scaling (RT-SVFS) techniques based on an optimal real-time scheduling algorithm for multiprocessors. The techniques are theoretically optimal when the voltage and frequency can be controlled both uniformly and independently among processors. Simulation results show that the independent RT-SVFS technique closely approaches the lower bound on energy consumption if the voltage and frequency can be controlled minutely.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133185321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Service oriented architecture (SOA) is becoming established in computing as a means to integrate processing and data across organisations. This paper proposes that system-level integration can benefit from service oriented architectural descriptions and loose coupling between the problem domain requirements and different system solutions. The problem domain is exemplified as military capability, from the UK Ministry of Defence (MoD), in particular, network enabled capability (NEC). Representations of military capability in the problem domain can be described in terms of processes. The processes are sequences of functions that can be described as services. Then different types of system solutions can implement the described services. Firstly, the paper presents an overview of conceptual SOA and in the context of military capability compares three levels of service integration: business services, systems services and computing services. Secondly, the paper presents a framework for evaluating the performance and effectiveness of service integration to compare different solutions in delivering military capability.
{"title":"Service-Oriented Integration of Systems for Military Capability","authors":"D. Russell, N. Looker, Lu Liu, Jie Xu","doi":"10.1109/ISORC.2008.45","DOIUrl":"https://doi.org/10.1109/ISORC.2008.45","url":null,"abstract":"Service oriented architecture (SOA) is becoming established in computing as a means to integrate processing and data across organisations. This paper proposes that system-level integration can benefit from service oriented architectural descriptions and loose coupling between the problem domain requirements and different system solutions. The problem domain is exemplified as military capability, from the UK Ministry of Defence (MoD), in particular, network enabled capability (NEC). Representations of military capability in the problem domain can be described in terms of processes. The processes are sequences of functions that can be described as services. Then different types of system solutions can implement the described services. Firstly, the paper presents an overview of conceptual SOA and in the context of military capability compares three levels of service integration: business services, systems services and computing services. Secondly, the paper presents a framework for evaluating the performance and effectiveness of service integration to compare different solutions in delivering military capability.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128678468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nizar Idoudi, Claude Duvallet, B. Sadeg, R. Bouaziz, F. Gargouri
A real-time database is a database in which both the data and the operations upon the data may have timing constraints. The design of this kind of database requires the introduction of new concepts to modelize both data structures and the dynamic behavior of the database. In this paper, we propose an UML2.0 profile, entitled UML-RTDB, allowing the design of structural model for a real-time database. One of the main advantages of UML-RTDB is its capacity to take into account real-time database properties through specialized concepts in rigourous, easy and expressive manner.
{"title":"Structural Model of Real-Time Databases: An Illustration","authors":"Nizar Idoudi, Claude Duvallet, B. Sadeg, R. Bouaziz, F. Gargouri","doi":"10.1109/ISORC.2008.80","DOIUrl":"https://doi.org/10.1109/ISORC.2008.80","url":null,"abstract":"A real-time database is a database in which both the data and the operations upon the data may have timing constraints. The design of this kind of database requires the introduction of new concepts to modelize both data structures and the dynamic behavior of the database. In this paper, we propose an UML2.0 profile, entitled UML-RTDB, allowing the design of structural model for a real-time database. One of the main advantages of UML-RTDB is its capacity to take into account real-time database properties through specialized concepts in rigourous, easy and expressive manner.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122025706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we propose a method to verify software executed on RTOS which conforms to mulTRON with a model checking tool Spin. The RTOS provides facilities such as priorities and service calls to control the execution of tasks, however, Spin does not provide them. Thus, we implemented a middleware which allows us to use the facilities and simulate the execution of the tasks in Spin. The paper shows how it is implemented and its evaluation.
{"title":"Model Checking Multi-Task Software on Real-Time Operating Systems","authors":"Toshiaki Aoki","doi":"10.1109/ISORC.2008.46","DOIUrl":"https://doi.org/10.1109/ISORC.2008.46","url":null,"abstract":"In this paper, we propose a method to verify software executed on RTOS which conforms to mulTRON with a model checking tool Spin. The RTOS provides facilities such as priorities and service calls to control the execution of tasks, however, Spin does not provide them. Thus, we implemented a middleware which allows us to use the facilities and simulate the execution of the tasks in Spin. The paper shows how it is implemented and its evaluation.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132105527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Time-triggered communication is a favored design strategy for safety-critical systems. However, the startup of time-triggered systems is a significant concern, since the time-line from which fault-tolerance is supported must be established in segmented mediums, e.g. multi-hop networks. The startup problems are particularly challenging since clique formation, i.e. the establishment of disjoint time-triggered communication sets, may be systematically induced. This paper presents an alternative startup solution based upon a braided-ring architecture called BRAIN (braided ring availability integrity network). Segmentation-induced cliques are particularly prevalent in this architecture, since each node presents a potential medium break. The described strategy dramatically improves startup performance in relation to current approaches by leveraging the cooperative action of adjacent nodes during startup and high-integrity data propagation.
{"title":"Starting and Resolving a Partitioned BRAIN","authors":"M. Paulitsch, B. Hall","doi":"10.1109/ISORC.2008.9","DOIUrl":"https://doi.org/10.1109/ISORC.2008.9","url":null,"abstract":"Time-triggered communication is a favored design strategy for safety-critical systems. However, the startup of time-triggered systems is a significant concern, since the time-line from which fault-tolerance is supported must be established in segmented mediums, e.g. multi-hop networks. The startup problems are particularly challenging since clique formation, i.e. the establishment of disjoint time-triggered communication sets, may be systematically induced. This paper presents an alternative startup solution based upon a braided-ring architecture called BRAIN (braided ring availability integrity network). Segmentation-induced cliques are particularly prevalent in this architecture, since each node presents a potential medium break. The described strategy dramatically improves startup performance in relation to current approaches by leveraging the cooperative action of adjacent nodes during startup and high-integrity data propagation.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126639915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The real-time specification for Java (RTSJ) extends the Java memory model through immortal and scoped memory regions to reduce the timing-indeterminism caused by garbage collection. Since scoped regions can be nested, RTSJ imposes strict assignment rules to avoid dangling pointers. These rules stabilise that an object shall not reference any object whose lifetime could be shorter than they own. Then references among two objects within different scoped regions are allowed only in one direction (i.e., from objects within region r1 to region r2, but never from r2 to r1). In order to support RTSJ component-based applications, we require controlled violations of the assignment rules to have bidirectional references among objects within two different scopes.
{"title":"Allowing Cycle References by Introducing Controlled Violations of the Assignment Rules in Real-Time Java","authors":"M. T. Higuera-Toledano","doi":"10.1109/ISORC.2008.48","DOIUrl":"https://doi.org/10.1109/ISORC.2008.48","url":null,"abstract":"The real-time specification for Java (RTSJ) extends the Java memory model through immortal and scoped memory regions to reduce the timing-indeterminism caused by garbage collection. Since scoped regions can be nested, RTSJ imposes strict assignment rules to avoid dangling pointers. These rules stabilise that an object shall not reference any object whose lifetime could be shorter than they own. Then references among two objects within different scoped regions are allowed only in one direction (i.e., from objects within region r1 to region r2, but never from r2 to r1). In order to support RTSJ component-based applications, we require controlled violations of the assignment rules to have bidirectional references among objects within two different scopes.","PeriodicalId":378715,"journal":{"name":"2008 11th IEEE International Symposium on Object and Component-Oriented Real-Time Distributed Computing (ISORC)","volume":"185 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121161921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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