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2011 Brazilian Symposium on Computing System Engineering最新文献

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sendmmsg: An Efficient System Call to Send Multiple Messages on Linux sendmsg:一个在Linux上发送多个消息的高效系统调用
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.36
Breno Leitão, Islene C. Garcia
{"title":"sendmmsg: An Efficient System Call to Send Multiple Messages on Linux","authors":"Breno Leitão, Islene C. Garcia","doi":"10.1109/SBESC.2011.36","DOIUrl":"https://doi.org/10.1109/SBESC.2011.36","url":null,"abstract":"This article describes the limitations of sendmsg, the current system call responsible for sending network messages in Linux. It is shown that this system call performance is not good enough, mainly when it needs to send a batch of similar data to many destinations in the network, as commonly experienced in IPTV servers. In order to prove that, a new system call has been implemented, sendmmsg, which acts similarly to the original one, but presenting some performance advantages, specially when sending similar data to peers. This new call needs only an extra parameter, when compared to the original one.(Portuguese version) Este artigo descreve as limitações da chamada de sistema sendmsg responsável por enviar mensagens de rede no sistema operacional Linux. É mostrado que tal chamada não possui um bom desempenho quando se necessita enviar vários pacotes em lote, contendo dados similares, para vários destinatários remotos -- caso comum em servidores de IPTV. Para tanto, é implementada uma nova função, sendmmsg, parecida com a original, porém, mais eficiente, apenas com o acréscimo de um parâmetro.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125600704","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}
引用次数: 1
An Adjustment of EDCA Protocol for Real-Time EDCA协议的实时调整
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.14
O. Alimenti, G. Friedrich, Guillermo H. Reggiani, Santiago Tonietti, Federico Maidana, Damián Gómez De Marco
{"title":"An Adjustment of EDCA Protocol for Real-Time","authors":"O. Alimenti, G. Friedrich, Guillermo H. Reggiani, Santiago Tonietti, Federico Maidana, Damián Gómez De Marco","doi":"10.1109/SBESC.2011.14","DOIUrl":"https://doi.org/10.1109/SBESC.2011.14","url":null,"abstract":"A network control system (NCS) on wireless networks (WNCS) presents problems of reliability and timing own of radio channel and the mechanisms of media access control (MAC) that cause unpredictable latency and packet loss. The EDCA (Enhanced Distributed Channel Access) MAC, of the 802.11e, provides four differentiated levels of Quality of Service (QoS) that do not guarantee a bounded delay for sending packets. This paper proposes to properly handle the contention window (CW), the backoff counter and arbitration inter-frame spaces (AIFS) of EDCA, to limit transmission latency and to avoid packet loss.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132728905","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}
引用次数: 3
Energy Saving in Server Clusters 服务器集群节能
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.31
G. Bottari, J. Leite
{"title":"Energy Saving in Server Clusters","authors":"G. Bottari, J. Leite","doi":"10.1109/SBESC.2011.31","DOIUrl":"https://doi.org/10.1109/SBESC.2011.31","url":null,"abstract":"The widespread use of Web services from the last years has been increasing the energy consumed by datacenters. This is both an economical and environmental concern, and has motivated research on techniques to make server clusters more energy-efficient. This work presents simple and scalable policies to manage servers, while attending the soft real-time characteristics of the applications. The proposed control is able to service requests at the specified deadline 95% of the times, achieving an energy saving of more than 50% on some cases. All experiments were validated on a physical testbed.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127374337","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}
引用次数: 1
Impact of the x86 System Management Mode in Real-Time Systems x86系统管理模式对实时系统的影响
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.41
R. A. Starke, R. S. Oliveira
{"title":"Impact of the x86 System Management Mode in Real-Time Systems","authors":"R. A. Starke, R. S. Oliveira","doi":"10.1109/SBESC.2011.41","DOIUrl":"https://doi.org/10.1109/SBESC.2011.41","url":null,"abstract":"There is a tendency toward the use of personal computers (PC) in real-time systems. These computers have highprocessing capacity and reduced costs when compared to software and hardware development fordedicated platforms. However, real-time systems require latency predictability and the processors of the x86architecture have aspecial protection and correction mode known as SystemManagement Mode (SMM). This mode is not traceable by the operating system and it can cause unpredictability in thesystem. This article describes the SMM, presents tools and methods for its detection and an analysis of its impacton real-time systems.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125219588","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}
引用次数: 1
A Communication Approach for Parallel Data Fusion in IEEE 802.15.4 Wireless Sensor Networks IEEE 802.15.4无线传感器网络中并行数据融合的通信方法
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.37
Gerson F. Budke, C. Montez, R. Moraes, P. Portugal
{"title":"A Communication Approach for Parallel Data Fusion in IEEE 802.15.4 Wireless Sensor Networks","authors":"Gerson F. Budke, C. Montez, R. Moraes, P. Portugal","doi":"10.1109/SBESC.2011.37","DOIUrl":"https://doi.org/10.1109/SBESC.2011.37","url":null,"abstract":"In this paper is proposed a communication approach for implementation of parallel data fusion techniques in IEEE 802.15.4 star networks. In the approach, the network configures itself in order to adjust the number of messages sent periodically by sensor nodes, establishing a trade-off between the number of sent messages and the dependability of data fusion in base station. Conventional techniques for data fusion can be employed using the proposed approach, such as Dempster-Shafer or Kalman filter. A prototype was implemented and experiments were carried out to evaluate the approach. Results showed the effectiveness of the proposal.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"240 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132828210","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}
引用次数: 0
A Proposal of Change to the Multiprocessor Priority Ceiling Protocol 多处理机优先级上限协议的修改建议
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.43
Andreu Carminati, R. S. Oliveira
{"title":"A Proposal of Change to the Multiprocessor Priority Ceiling Protocol","authors":"Andreu Carminati, R. S. Oliveira","doi":"10.1109/SBESC.2011.43","DOIUrl":"https://doi.org/10.1109/SBESC.2011.43","url":null,"abstract":"In uniprocessor real-time systems, resource sharing is usually done using protocols such as Stack Resource Policy, Priority Ceiling Protocol and Priority Inheritance Protocol. Unfortunately these protocols did not work as expected on real-time multiprocessor systems. Such problem must be addressed with different approaches like Multiprocessor Priority Ceiling Protocol (MPCP) and Multiprocessor Stack Resource Policy (MSRP). The objective of this paper is to propose a variation of the MPCP protocol and a possible implementation, including an experimental evaluation.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124218865","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}
引用次数: 1
Empirical Study about Using aiT Tool in WCET Estimation aiT工具在WCET估计中的应用实证研究
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.42
R. A. Starke, R. S. Oliveira
{"title":"Empirical Study about Using aiT Tool in WCET Estimation","authors":"R. A. Starke, R. S. Oliveira","doi":"10.1109/SBESC.2011.42","DOIUrl":"https://doi.org/10.1109/SBESC.2011.42","url":null,"abstract":"The determination of upper bounds of execution time (Worst-Case Execution Time -- WCET) of tasks is an importantstep in the development and validation of safety-critical hard real-time systems. Measurement based methods arenot considered safe and the static code analysis is know to be a difficult problem if the underling processorarchitecture uses cache memories, pipelines and speculative components. This article presents an empiric study ofthe aiT WCET tool, considered one of the best. There is a tool description, its methods and some analyzed testcode for the ARM7 processor.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128386580","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}
引用次数: 0
A Tool to Support Model-Based Testing Activities 支持基于模型的测试活动的工具
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.12
Gilson Doi Junior, A. Bonifácio
{"title":"A Tool to Support Model-Based Testing Activities","authors":"Gilson Doi Junior, A. Bonifácio","doi":"10.1109/SBESC.2011.12","DOIUrl":"https://doi.org/10.1109/SBESC.2011.12","url":null,"abstract":"The occurrence of fault on embedded critical systems can result in financial damage and human losses, as well. Rigorous approaches based on formalisms, specially testing routines, have been proposed to guarantee more reliable systems. Model-based testing is a rigorous approach to support testing activities, e.g. test case generation. Theoretical results have been validated in the literature, but there are few tools to support practical applications. Thus, we develop a tool to support practical experiments which allows us to make a comparison among model-based test case generation methods by pointing more suitable sceneries for each one.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133350877","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}
引用次数: 1
A Model for Reconfiguration of Multi-Modal Real-Time Systems under Energy Constraints 能量约束下多模态实时系统重构模型
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.9
Ríad Nassiffe, E. Camponogara, George Lima
{"title":"A Model for Reconfiguration of Multi-Modal Real-Time Systems under Energy Constraints","authors":"Ríad Nassiffe, E. Camponogara, George Lima","doi":"10.1109/SBESC.2011.9","DOIUrl":"https://doi.org/10.1109/SBESC.2011.9","url":null,"abstract":"The problem of maximizing quality of service (QoS) of real-time systems subject to both schedulability and energy constraints is addressed. A discrete system consisting of tasks with multiple operating modes, and which can be executed by the processor at different frequency/voltage levels, is considered. Although the system reconfiguration scheme assumes the earliest deadline first (EDF) policy and soft real-time tasks, it can be extended to other scheduling policies and handle hard real-time tasks. The described solution is suitable for adaptive real-time embedded systems which require energy savings associated to QoS. Despite being NP-Hard, the reconfiguration problem can be solved with a mixed-integer linear-programing solver sufficiently fast.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"207 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116395419","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}
引用次数: 0
Use of Neural Networks in the Management of Virtual Web Servers 神经网络在虚拟Web服务器管理中的应用
2011 Brazilian Symposium on Computing System Engineering Pub Date : 2011-11-07 DOI: 10.1109/SBESC.2011.35
A. Monteiro, Marcus Vinicius Azevedo, Alexandre Sztajnberg
{"title":"Use of Neural Networks in the Management of Virtual Web Servers","authors":"A. Monteiro, Marcus Vinicius Azevedo, Alexandre Sztajnberg","doi":"10.1109/SBESC.2011.35","DOIUrl":"https://doi.org/10.1109/SBESC.2011.35","url":null,"abstract":"This work proposes using a neural network with self organizing maps, to build a configuration policy, which enables the management of a supporting infrastructure for Web applications using virtual machines. The neural network classifies the cluster´s operation states to perform configuration operations adding or subtracting resources from the cluster. The overall goal is to ensure quality of service required by the application, while trying to save energy, acting efficiently on physical servers (hosts) or manipulating the VMs. The work includes a performance evaluation carried out over a system implemented based on the proposed architecture.","PeriodicalId":147899,"journal":{"name":"2011 Brazilian Symposium on Computing System Engineering","volume":"209 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129958549","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}
引用次数: 1
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