{"title":"Multi-dimensional Robustness Optimization in Heterogeneous Distributed Embedded Systems","authors":"A. Hamann, R. Racu, R. Ernst","doi":"10.1109/RTAS.2007.19","DOIUrl":"https://doi.org/10.1109/RTAS.2007.19","url":null,"abstract":"Embedded system optimization typically considers objectives such as cost, timing, buffer sizes, and power consumption. Robustness criteria, i.e. sensitivity of the system to property variations like execution and transmission delays, input data rates, CPU clock rates, etc., has found less attention despite its practical relevance. In this paper we present an approach for optimizing multidimensional robustness criteria in complex distributed embedded systems. The key novelty of our approach is a scalable stochastic multi-dimensional sensitivity analysis technique approximating the sought-after sensitivity front from two sides, i.e. coming from the space of working and from the space of non-working system property combinations. We utilize the proposed stochastic sensitivity analysis to derive multi-dimensional robustness metrics, which are capable of bounding the robustness of given system configurations with little computational effort. The proposed metrics can significantly speed up multidimensional robustness optimization by quickly identifying promising system configurations, whose in-depth robustness evaluation can be performed subsequently to the optimization process","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121049509","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}
{"title":"Full Duplex Switched Ethernet for Next Generation \"1553B\"-Based Applications","authors":"A. Mifdaoui, F. Frances, C. Fraboul","doi":"10.1109/RTAS.2007.13","DOIUrl":"https://doi.org/10.1109/RTAS.2007.13","url":null,"abstract":"Over the last thirty years, the MIL-STD 1553B data bus has been used in many embedded systems, like aircrafts, ships, missiles and satellites. However, the increasing number and complexity of interconnected subsystems lead to emerging needs for more communication bandwidth. Therefore, a new interconnection system is needed to overcome the limitations of the MIL-STD 1553B data bus. Among several high speed networks, full duplex switched Ethernet is put forward here as an attractive candidate to replace the MIL-STD 1553B data bus. However, the key argument against switched Ethernet lies in its non-deterministic behavior that makes it inadequate to deliver hard time-constrained communications. Hence, our primary objective in this paper is to achieve an accepted QoS level offered by switched Ethernet, to support diverse \"1553B\"-based applications requirements. We evaluate the performance of traffic shaping techniques on full duplex switched Ethernet with an adequate choice of service strategy in the switch, to guarantee the real-time constraints required by these specific 1553B-based applications. An analytic study is conducted, using the network calculus formalism, to evaluate the deterministic guarantees offered by our approach. Theoretical analysis are then investigated in the case of a realistic \"1553B\"-based application extracted from a real military aircraft network. The results herein show the ability of profiled full duplex switched Ethernet to satisfy 1553B-like real-time constraints","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128424191","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}
{"title":"A Programming Model for Time-Synchronized Distributed Real-Time Systems","authors":"Yang Zhao, Jie Liu, Edward A. Lee","doi":"10.1109/RTAS.2007.5","DOIUrl":"https://doi.org/10.1109/RTAS.2007.5","url":null,"abstract":"Discrete-event (DE) models are formal system specifications that have analysable deterministic behaviors. Using a global, consistent notion of time, DE components communicate via time-stamped events. DE models have primarily been used in performance modeling and simulation, where time stamps are a modeling property bearing no relationship to real time during execution of the model. In this paper, we extend DE models with the capability of relating certain events to physical time. We propose a programming model, called PTIDES (programming temporally integrated distributed embedded systems), which has DE semantics, but with carefully chosen relations between model time and real time. Key to making this model effective is to ensure that constraints that guarantee determinacy in the semantics are preserved at runtime. To accomplish this, we give a distributed execution strategy that obeys DE semantics without the penalty of totally ordered executions based on time stamps. Our technique relies on having a distributed common notion of time, known to some precision. Based on causality analysis of DE models, we define relevant dependency and relevant orders to enable out-of-order execution without compromising determinism and without requiring backtracking","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128172386","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}
Yuanfang Zhang, Chenyang Lu, C. Gill, P. Lardieri, Gautam H. Thaker
{"title":"Middleware Support for Aperiodic Tasks in Distributed Real-Time Systems","authors":"Yuanfang Zhang, Chenyang Lu, C. Gill, P. Lardieri, Gautam H. Thaker","doi":"10.1109/RTAS.2007.16","DOIUrl":"https://doi.org/10.1109/RTAS.2007.16","url":null,"abstract":"Many mission-critical distributed real-time applications must handle aperiodic tasks with end-to-end deadlines. However, existing middleware (e.g., RT-CORBA) lacks schedulability analysis and run-time enforcement mechanisms needed to give online real-time guarantees for aperiodic tasks. The primary contribution of this work is the design, implementation, and performance evaluation of the first realization of deferrable server and admission control mechanisms for aperiodic tasks in middleware. Empirical results on a KURT-Linux testbed demonstrate the efficiency and effectiveness of our deferrable server and admission control mechanisms in TAO's federated event service","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128327876","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}
{"title":"Minimising Task Migration and Priority Changes in Mode Transitions","authors":"P. Emberson, I. Bate","doi":"10.1109/RTAS.2007.17","DOIUrl":"https://doi.org/10.1109/RTAS.2007.17","url":null,"abstract":"Handling mode changes is one of the most complex and important problems for real-time systems designers. The challenge is to move a system from running one set of software to another while still achieving the quality of service guarantees necessary. There has been previous work which concentrated on how to perform scheduling and timing analysis of mode changes. However, a common theme of all this research is that if the system's schedule and allocation is chosen to minimise the set of differences between modes then the mode transition problem can be performed more easily and quickly. This paper investigates how this can be achieved","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133573168","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}
J. Calandrino, Dan P. Baumberger, Tong Li, Scott Hahn, James H. Anderson
{"title":"Soft Real-Time Scheduling on Performance Asymmetric Multicore Platforms","authors":"J. Calandrino, Dan P. Baumberger, Tong Li, Scott Hahn, James H. Anderson","doi":"10.1109/RTAS.2007.35","DOIUrl":"https://doi.org/10.1109/RTAS.2007.35","url":null,"abstract":"This paper discusses an approach for supporting soft real-time periodic tasks in Linux on performance asymmetric multicore platforms (AMPs). Such architectures consist of a large number of processing units on one or several chips, where each processing unit is capable of executing the same instruction set at a different performance level. We discuss deficiencies of Linux in supporting periodic real-time tasks, particularly when cores are asymmetric, and how such deficiencies were overcome. We also investigate how to provide good performance for non-real-time tasks in the presence of a real-time workload. We show that this can be done by using deferrable servers to explicitly reserve a share of each core for non-real-time tasks. This allows non-real-time tasks to have priority over real-time tasks when doing so will not cause timing requirements to be violated, thus improving non-real-time response times. Experiments show that even small deferrable servers can have a dramatic impact on non-real-time task performance","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114335809","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}
B. Mochocki, D. Rajan, X. Hu, C. Poellabauer, Kathleen Otten, Thidapat Chantem
{"title":"Network-Aware Dynamic Voltage and Frequency Scaling","authors":"B. Mochocki, D. Rajan, X. Hu, C. Poellabauer, Kathleen Otten, Thidapat Chantem","doi":"10.1109/RTAS.2007.20","DOIUrl":"https://doi.org/10.1109/RTAS.2007.20","url":null,"abstract":"Reducing energy consumption is an important consideration in embedded real-time system development. This work examines systems that contain a DVFS managed CPU executing packet producing tasks and a DPM-controlled network interface. We introduce a novel approach to minimize energy consumed by the network resource on such a system, through careful selection of voltage and frequency levels on the CPU. Contrary to existing claims which state that DVFS should not be employed when the CPU is not a significant consumer of energy, we show that our DVFS technique can reduce system energy by as much as 35%, even when the CPU energy consumption is negligible. Furthermore, we motivate the need to balance the CPU and network energy and present two techniques to do so. One is based on off-line analysis and the other is a conservative on-line approach. We then validate the proposed methods using both simulation and an implementation in the Linux kernel","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"151 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115549129","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}
P. Basanta-Val, L. Almeida, M. García-Valls, I. Estévez-Ayres
{"title":"Towards a Synchronous Scheduling Service on Top of a Unicast Distributed Real-Time Java","authors":"P. Basanta-Val, L. Almeida, M. García-Valls, I. Estévez-Ayres","doi":"10.1109/RTAS.2007.40","DOIUrl":"https://doi.org/10.1109/RTAS.2007.40","url":null,"abstract":"This paper describes an approach towards the definition and implementation of a synchronization service on top of a remote object model offered by an unicast real-time remote object paradigm. Also an architecture model based on the RTSJ (real-time specification for Java) and the distribution middleware RMI (remote method invocation) specifications is proposed in order to give support to the model, defining a convergence layer that manages the underlying resources involved in a master-slave communication through a new API. Finally, preliminary results from an implementation prototype show the feasibility of the model and provide an initial estimation of jitters and the performance of the synchronization service","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126224316","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}
{"title":"Resource-Locking Durations in EDF-Scheduled Systems","authors":"N. Fisher, M. Bertogna, Sanjoy Baruah","doi":"10.1109/RTAS.2007.32","DOIUrl":"https://doi.org/10.1109/RTAS.2007.32","url":null,"abstract":"The duration of time for which each application locks each shared resource is critically important in composing multiple independently-developed applications upon a shared \"open\" platform. The concept of resource hold time (RHT) - the largest length of time that may elapse between the instant that an application system locks a resource and the instant that it subsequently releases the resource - is formally defined and studied in this paper. An algorithm is presented for computing resource hold times for every resource in an application that is scheduled using earliest deadline first scheduling, with resource access arbitrated using the stack resource policy. An algorithm is presented for decreasing these RHT's without changing the semantics of the application or compromising application feasibility","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133990728","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}
{"title":"Efficient Computation of Buffer Capacities for Cyclo-Static Real-Time Systems with Back-Pressure","authors":"M. Wiggers, M. Bekooij, P. Jansen, G. Smit","doi":"10.1109/RTAS.2007.12","DOIUrl":"https://doi.org/10.1109/RTAS.2007.12","url":null,"abstract":"This paper describes a conservative approximation algorithm that derives close to minimal buffer capacities for an application described as a cyclo-static dataflow graph. The resulting buffer capacities satisfy constraints on the maximum buffer capacities and end-to-end throughput and latency constraints. Furthermore we show that the effects of run-time arbitration can be included in the response times of dataflow actors. We show that modelling an MP3 playback application as a cyclo-static dataflow graph instead of a multi-rate dataflow graph results in buffer capacities that are reduced up to 39%. Furthermore, the algorithm is applied to a real-life car-radio application, in which two independent streams are processed","PeriodicalId":222543,"journal":{"name":"13th IEEE Real Time and Embedded Technology and Applications Symposium (RTAS'07)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127168893","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}