{"title":"The MIDdleware Assurance Substrate: Enabling Strong Real-Time Guarantees in Open Systems with OpenFlow","authors":"Andrew L. King, Sanjian Chen, Insup Lee","doi":"10.1109/ISORC.2014.49","DOIUrl":"https://doi.org/10.1109/ISORC.2014.49","url":null,"abstract":"Middleware designed for use in Distributed Real-Time and Embedded (DRE) systems enable cost and development time reductions by providing simple communications abstractions and hiding operating system-level networking API details from developers. While current middleware technologies can hide many low-level details, designers must provide a static configuration for the system's underlying network in order to achieve required performance characteristics. This has not been a problem for many types of DRE systems where the configuration of the system is relatively fixed from the factory (e.g., aircraft or naval vessels). However for truly open systems (i.e., systems where end users can add or substract components at runtime)the standard static network configuration approach cannot guarantee that required performance will be met because network resource demands are not fully known a priori. Open systems with stringent performance requirements need middleware that can dynamically manage the underlying network configuration automatically in response to changing demands. Fortunately, recent trends in networking have resulted in a wide variety of networking equipment that expose a standardized low-level interface to their configuration via the OpenFlow protocol. In this paper we discuss how OpenFlow can be leveraged by DRE middleware to automatically provide performance guarantees. In order to make the discussion concrete, we describe the architecture of our prototype middleware MIDAS as well as the details of one example network resource management strategy. We demonstrate the feasibility of our approach via performance assesment of a simple DRE application using our MIDAS and commerically available OpenFlow hardware.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125694724","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":"An Operating System for Safety-Critical Applications on Manycore Processors","authors":"Florian Kluge, M. Gerdes, T. Ungerer","doi":"10.1109/ISORC.2014.30","DOIUrl":"https://doi.org/10.1109/ISORC.2014.30","url":null,"abstract":"Processor technology is advancing from bus-based multicores to network-on-chip-based many cores, posing new challenges for operating system design. In this paper, we discuss why future safety-critical systems can profit from such new architectures. To make the potentials of many core processors usable in safety-critical systems, we devise the operating system MOSSCA that is adapted to the special requirements prevailing in this domain. MOSSCA introduces abstractions that support an application developer in his work of writing safety-critical applications. Internally, MOSSCA runs in a distributed manner to achieve a high parallelism while still guaranteeing a predictable behaviour.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127182096","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":"Unmanned Aerial Vehicle as Data Mule for Connecting Disjoint Segments of Wireless Sensor Network with Unbalanced Traffic","authors":"T. Heimfarth, J. Araujo, J. Giacomin","doi":"10.1109/ISORC.2014.51","DOIUrl":"https://doi.org/10.1109/ISORC.2014.51","url":null,"abstract":"This paper presents a method for federating disjoint segments of Wireless Sensor Networks (WSNs) in the presence of unbalanced traffic. The approach relies on an Unmanned Aerial Vehicle (UAV) for message ferrying. Network disconnections compromise the system operation, ergo an alternative to mitigate disconnections is important to extend the network lifetime. In our work, a UAV becomes a data mule, carrying physically packets across the disjoint partitions to assure network connection. The method presented in this article goes beyond previous work by taking into account the traffic situation among the network segments: highly communicating disjoint segments are visited more frequently than partitions with low outgoing/incoming traffic. Simulations realized evince the effectiveness of our system for concentrated traffic. In this case, a lower latency and data loss resulted when compared with the system without prioritization of highly communicating segments.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128579266","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 Synchronization in Hierarchically Scheduled Real-Time Systems Using Preemptive Critical Sections","authors":"Tom Springer, Steffen Peter, T. Givargis","doi":"10.1109/ISORC.2014.50","DOIUrl":"https://doi.org/10.1109/ISORC.2014.50","url":null,"abstract":"In this paper we outline a novel approach for accessing mutually exclusive resources in hierarchically scheduled real-time systems. Our method known as the Resource Access Control Protocol with Preemption (RACPwP) is an improved resource allocation protocol which utilizes preemptive critical sections to provide guaranteed determinism for hard real-time tasks and comparable response times for soft real-time tasks. Our experiments demonstrated that RACPwP outperforms other state-of-the-art resource access control protocols used in hierarchically scheduled systems. RACPwP was implemented as part of VxWorks and evaluated in an actual embedded application used in the aerospace industry. As a result, the response times for hard real-time tasks were improved over a traditional resource synchronization protocol.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124463954","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":"iPlace: An Intelligent and Tunable Power- and Performance-Aware Virtual Machine Placement Technique for Cloud-Based Real-Time Applications","authors":"Faruk Caglar, Shashank Shekhar, A. Gokhale","doi":"10.1109/ISORC.2014.35","DOIUrl":"https://doi.org/10.1109/ISORC.2014.35","url":null,"abstract":"Power and performance tradeoffs are critical and challenging issues faced by cloud service providers (CSPs) while managing their data centers. On the one hand, CSPs strive to reduce power consumption of their data centers to not only decrease their energy costs but to also reduce adverse impact on the environment. On the other hand, CSPs must deliver performance expected by the applications hosted in their cloud in accordance with predefined Service Level Agreements (SLAs). Not doing so will lead to loss of customers and thereby major revenue losses for the CSPs. Addressing these dual set of challenges is hard for the CSPs because power management and performance assurance are conflicting objectives, particularly in the context of multi-tenant cloud systems where multiple virtual machines (VMs) may be hosted on a single physical server. The problem becomes even harder when real-time applications are hosted in these VMs. To address these challenges and make appropriate tradeoffs, we present iPlace, which is an intelligent and tunable power- and performance-aware VM placement middleware. The placement strategy is based on a two-level artificial neural network which predicts (1) CPU usage at the first level, and (2) power consumption and performance of a host machine at the second level that uses the predicted CPU usage. The efficacy of iPlace is evaluated in the context of a VM consolidation algorithm that is applied to running virtual machines and host machines in a private cloud.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116166321","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}
IV RobertG.Pettit, Navneet Mezcciani, Julie S. Fant
{"title":"On the Needs and Challenges of Model-Based Engineering for Spaceflight Software Systems","authors":"IV RobertG.Pettit, Navneet Mezcciani, Julie S. Fant","doi":"10.1109/ISORC.2014.13","DOIUrl":"https://doi.org/10.1109/ISORC.2014.13","url":null,"abstract":"Space flight software continues to experience exponential growth as functionality migrates from hardware to software. The resulting complexity of these mission critical systems demands new approaches to software systems engineering in order to effectively manage the development efforts and ensure that reliability is not compromised. Model-based systems/software engineering (MBE) approaches present attractive solutions to address the size and complexity through abstraction and analytical models. However, there are many challenges that must be addressed before MBE approaches can be effectively adopted on a large scale across an entire system. In this paper, we discuss some of the key motivators and challenges based on our experiences with flight software programs employing elements of MBE.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126118132","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":"Accelerator-Aware Task Synchronization for Real-Time Systems","authors":"Yu-Chen Wu, Che-Wei Chang, Tei-Wei Kuo, C. Shih","doi":"10.1109/ISORC.2014.18","DOIUrl":"https://doi.org/10.1109/ISORC.2014.18","url":null,"abstract":"This work is motivated by the needs to synchronize task executions where tasks might use semaphores to protect their critical sections and run over accelerators. In particular, the Priority Ceiling Protocol is extended to manage priority inversion caused by accelerator usages. By recognizing the difference between an accelerator and a semaphore, higher-priority tasks are less likely blocked by lower-priority tasks, due to their requests for an accelerator. In particular, blocking that will not contribute to any deadlock and/or chained blocking is allowed in a managed way, with an objective to maximize the utilization of accelerators. A series of experiments is then conducted to derive insights to task synchronization when accelerators might be used.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126118900","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":"WCET-Based Comparison of an Instruction Scratchpad and a Method Cache","authors":"J. Whitham, Martin Schoeberl","doi":"10.1109/ISORC.2014.48","DOIUrl":"https://doi.org/10.1109/ISORC.2014.48","url":null,"abstract":"This paper compares two proposed alternatives to conventional instruction caches: a scratchpad memory (SPM) and a method cache. The comparison considers the true worst-case execution time (WCET) and the estimated WCET bound of programs using either an SPM or a method cache, using large numbers of randomly generated programs. For these programs, we find that a method cache is preferable to an SPM if the true WCET is used, because it leads to execution times that are no greater than those for SPM, and are often lower. However, we also find that analytical pessimism is a significant problem for a method cache. If WCET bounds are derived by analysis, the WCET bounds for an instruction SPM are often lower than the bounds for a method cache. This means that an SPM may be preferable in practical systems.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"147 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127255108","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":"Analyzing the Overhead of Self-Optimization through Task Migration within a Decentralized Task Control Mechanism for Dependable System-on-Chip Architectures","authors":"Benjamin Betting, U. Brinkschulte","doi":"10.1109/ISORC.2014.29","DOIUrl":"https://doi.org/10.1109/ISORC.2014.29","url":null,"abstract":"This article presents our concept of an artificial hormone system for realizing a completely decentralized self-organizing and real-time capable task control mechanism using self-X properties. Besides the fundamentals of the prior hormone concept and the implementation model, we present latest results of our research: specification and analysis of an accurate timing model according the self-optimization procedure, using global task migration across a redundant multi-core SoC architecture. Furthermore we validate and compare the overhead in task migration towards the performance gain in execution, leading to first assessment in efficiency and profitability of the migration based optimization schemes.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122819386","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":"Introducing Virtual Accelerators to Decrease the Communication Overhead of an Artificial Hormone System for Task Allocation","authors":"U. Brinkschulte","doi":"10.1109/ISORC.2014.23","DOIUrl":"https://doi.org/10.1109/ISORC.2014.23","url":null,"abstract":"The Artificial Hormone System (AHS) is a completely decentralized operation principle for a middleware which can be used to allocate tasks in a system of heterogeneous processing elements (PEs) or cores. Tasks are scheduled according to their suitability for the heterogeneous PEs, the current PE load and task cooperation. The AHS also provides properties like self-configuration, self-optimization and self-healing by task allocation. The AHS is able to guarantee real time bounds for such self-X-properties. In order to cluster cooperating tasks on neighboring PEs, the AHS uses accelerator hormones. If a task is taken on a PE, it spreads these accelerator hormones in the vicinity to attract cooperating tasks thus reducing the communication distances. However, spreading the accelerator hormones produces additional communication overhead which can be significant in larger systems. In this paper the concept of virtual accelerators is introduced to completely avoid the overhead. Virtual accelerators are calculated locally instead of sending physical accelerators via the network. This can be achieved by exploiting the relationship between accelerators and other hormones. We show that virtual accelerators do neither change task clustering properties nor real-time behavior of the AHS, but are able to completely avoid the corresponding communication overhead.","PeriodicalId":217568,"journal":{"name":"2014 IEEE 17th International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131272098","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}