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Labeled Network Stack: A High-Concurrency and Low-Tail Latency Cloud Server Framework for Massive IoT Devices

Journal of Computer Science & Technology 2020年第1期35卷 179-193页

作者： Wen-Li Zhang Ke Liu Yi-Fan Shen Ya-Zhu Lan Hui Song Ming-Yu Chen Yuan-Fei Chen State Key Laboratory of Computer Architecture Institute of Computing TechnologyChinese Academy of Sciences Beijing 100190China University of Chinese Academy of Sciences Beijing 100049China Peng Cheng Laboratory Shenzhen 518000China Zhongke Zhicheng Electronic Technology Company Limited Jining 272000China

Internet of Things(IoT)applications have massive client connections to cloud servers,and the number of networked IoT devices is remarkably increasing.IoT services require both low-tail Latency and high concurrency in datacenters.This study aims to determine whether an order of magnitude improvement is possible in tail Latency and concurrency in mainstream systems by proposing a hardware-software codesigned labeled network stack(LNS)for future datacenters.The key innovation is a cross-layered payload labeling mechanism that distinguishes different requests by payload across the full network stack,including application,TCP/IP,and Ethernet layers.This type of design enables prioritized data packet processing and forwarding along the full datapath,such that Latency-insensitive requests cannot significantly interfere with high-priority requests.We build a prototype datacenter server to evaluate the LNS design against a commercial X86 server and the mTCP research,using a cloud-supported IoT application scenario.Experimental results show that the LNS design can provide an order of magnitude improvement in tail Latency and concurrency.A single datacenter server node can support over 2 million concurrent long-living connections for IoT devices as a 99-percentile tail Latency of 50 ms is maintained.In addition,the hardware-software codesign approach remarkably reduces the labeling and prioritization overhead and constrains the interference of high-priority requests to low-priority requests.

关键词： tail Latency high concurrency network stack cloud server Internet of Things(IoT)service

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A Task Allocation Method for Stream Processing with Recovery Latency Constraint

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Journal of Computer Science & Technology 2018年第6期33卷 1125-1139页

作者： Hong-Liang Li Jie Wu Zhen Jiang Xiang Li Xiao-Hui Wei College of Computer Science and Technology Jilin University Changchun 130012 China Key Laboratory of Symbolic Computation and Knowledge Engineering of the Ministry of Education Changchun 130012 China Department of Computer and Information Sciences Temple University Philadelphia PA 19122 U.S.A. Department of Computer Science West Chester University of Pennsylvania West Chester PA 19383 U.S.A.

Stream processing applications continuously process large amounts of online streaming data in real time or nearreal time. They have strict Latency constraints. However, the continuous processing makes them vulnerable to any failures,and the recoveries may slow down the entire processing pipeline and break Latency constraints. The upstream backupscheme is one of the most widely applied fault-tolerant schemes for stream processing systems. It introduces complexbackup dependencies to tasks, which increases the difficulty of controlling recovery latencies. Moreover, when dependenttasks are located on the same processor, they fail at the same time in processor-level failures, bringing extra recovery latencies that increase the impacts of failures. This paper studies the relationship between the task allocation and therecovery Latency of a stream processing application. We present a correlated failure effect model to describe the recoveryLatency of a stream topology in processor-level failures under a task allocation plan. We introduce a recovery-Latency awaretask allocation problem （RTAP） that seeks task allocation plans for stream topologies that will achieve guaranteed recoverylatencies. We discuss the difference between RTAP and classic task allocation problems and present a heuristic algorithmwith a computational complexity of O（n log2 n） to solve the problem. Extensive experiments were conducted to verify thecorrectness and effectiveness of our approach. It improves the resource usage by 15%-20% on average.

关键词： stream processing task allocation fault-tolerance upstream backup, recovery Latency

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The immunology of human cytomegalovirus Latency： could latent infection be cleared by novel immunotherapeutic strategies？

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Cellular & Molecular Immunology 2015年第2期12卷 128-138页

作者： Mark R Wills Emma Poole Betty Lau Ben Krishna John H Sinclair Department of Medicine University of Cambridge Cambridge UK

While the host immune response following primary human cytomegalovirus （HCMV） infection is generally effective at stopping virus replication and dissemination, virus is never cleared by the host and like all herpesviruses, persists for life. At least in part, this persistence is known to be facilitated by the ability of HCMV to establish Latency in myeloid cells in which infection is essentially silent with, importantly, a total lack of new virus production. However, although the viral transcription programme during Latency is much suppressed, a number of viral genes are expressed during latent infection at the protein level and many of these have been shown to have profound effects on the latent cell and its environment. Intriguingly, many of these Latency-associated genes are also expressed during lyric infection. Therefore, why the same potent host immune responses generated during lytic infection to these viral gene products are not recognized during Latency, thereby allowing clearance of latently infected cells, is far from clear. Reactivation from Latency is also a major cause of HCMV-mediated disease, particularly in the immune compromised and immune naive, and is also likely to be a major source of virus in chronic subclinical HCMV infection which has been suggested to be associated with long-term diseases such as atherosclerosis and some neoplasias. Consequently, understanding Latency and why latenUy infected cells appear to be immunoprivileged is crucial for an understanding of the pathogenesis of HCMV and may help to design strategies to eliminate latent virus reservoirs, at least in certain clinical settings.

关键词： Cytomegalovirus Latency immune evasion immunotherapeutic

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Hierarchical Content Caching in Fog Radio Access Networks:Ergodic Rate and Transmit Latency

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China Communications 2016年第12期13卷 1-14页

作者： Shiwei Jia Yuan Ai Zhongyuan Zhao Mugen Peng Chunjing Hu Key Laboratory of Universal Wireless Communications for Ministry of Education Beijing University of Posts and Telecommunications

In order to alleviate capacity constraints on the fronthaul and decrease the transmit Latency, a hierarchical content caching paradigm is applied in the fog radio access networks(F-RANs). In particular, a specific cluster of remote radio heads is formed through a common centralized cloud at the baseband unit pool, while the local content is directly delivered at fog access points with edge cache and distributed radio signal processing capability. Focusing on a downlink F-RAN, the explicit expressions of ergodic rate for the hierarchical paradigm is derived. Meanwhile, both the waiting delay and Latency ratio for users requiring a single content are exploited. According to the evaluation results of ergodic rate on waiting delay, the transmit Latency can be effectively reduced through improving the capacity of both fronthaul and radio access links. Moreover, to fully explore the potential of hierarchical content caching, the transmit Latency for users requiring multiple content objects is optimized as well in three content transmission cases with different radio access links. The simulation results verify the accuracy of the analysis, further show the Latency decreases significantly due to the hierarchical paradigm.

关键词： fog radio access network hierarchical content caching Latency ergodic rate

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Flow Latency analysis of component-based embedded software:Model and methodology

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International Journal of Modeling, Simulation, and Scientific Computing 2014年第4期5卷 123-138页

作者： Lei Tang Hanbo Wang School of Information Engineering Chang’an University Xi’anP.R.China ShaanXi Regional Electric Power Group co. Ltd Xi’anP.R.China

A wide variety of ways to analyze the end-to-end Latency emerges due to the feature of component-based software.The researchers began to see that the Latency is more sensitive to the data and control flows than the software architecture.However,for an embedded software,the Latency depends upon the hardware heavily.To illuminate the feature clearly,we extend the atomic model of component-based software first.A way to specify the flows involved is further developed to identify the end-to-end Latency.What is more,a novel methodology that bridges the gap between a constraint on Latency and an execution platform is proposed for the embedded software.By constructing a hierarchical architecture,it is available to consider the methodology as a decision problem where the satisfiability module theory(SMT)can be applied.Experimental results demonstrate how the Latency analysis conducts with the proposed model and methodology for the complex software architecture.

关键词： Latency flow component embedded software

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Joint Optimization of Energy Consumption and Network Latency in Blockchain-Enabled Fog Computing Networks

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China Communications 2024年第4期21卷 104-119页

作者： Huang Xiaoge Yin Hongbo Cao Bin Wang Yongsheng Chen Qianbin Zhang Jie School of Communications and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China School of Communication and Information Engineering University of SheffieldUnited Kingdom

Fog computing is considered as a solution to accommodate the emergence of booming requirements from a large variety of resource-limited Internet of Things(IoT)devices.To ensure the security of private data,in this paper,we introduce a blockchain-enabled three-layer device-fog-cloud heterogeneous network.A reputation model is proposed to update the credibility of the fog nodes(FN),which is used to select blockchain nodes(BN)from FNs to participate in the consensus process.According to the Rivest-Shamir-Adleman(RSA)encryption algorithm applied to the blockchain system,FNs could verify the identity of the node through its public key to avoid malicious attacks.Additionally,to reduce the computation complexity of the consensus algorithms and the network overhead,we propose a dynamic offloading and resource allocation(DORA)algorithm and a reputation-based democratic byzantine fault tolerant(R-DBFT)algorithm to optimize the offloading decisions and decrease the number of BNs in the consensus algorithm while ensuring the network security.Simulation results demonstrate that the proposed algorithm could efficiently reduce the network overhead,and obtain a considerable performance improvement compared to the related algorithms in the previous literature.

关键词： blockchain energy consumption fog computing network Internet of Things Latency

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Improved Algorithm for Broadcast Scheduling of Minimal Latency in Wireless Ad Hoc Networks

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Acta Mathematicae Applicatae Sinica 2010年第1期26卷 13-22页

作者： Wei-ping Shang Peng-jun Wan Xiao-dong Hu Department of Mathematics Zhengzhou University Zhengzhou 450052 China Department of Computer Science Illinois Institute of Technology Chicago IL 60616 USA Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

A wide range of applications for wireless ad hoc networks are time-critical and impose stringent requirement on the communication Latency. One of the key communication operations is to broadcast a message from a source node. This paper studies the minimum Latency broadcast scheduling problem in wireless ad hoc networks under collision-free transmission model. The previously best known algorithm for this NP-hard problem produces a broadcast schedule whose Latency is at least 648（rmax/rmin）^2 times that of the optimal schedule, where rmax and rmin are the maximum and minimum transmission ranges of nodes in a network, respectively. We significantly improve this result by proposing a new scheduling algorithm whose approximation performance ratio is at most （1 ＋ 2rmax/rmin）^2＋32, Moreover, under the proposed scheduling each node just needs to forward a message at most once.

关键词： Broadcast Latency wireless ad hoc networks approximation algorithm

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软件流水中隐藏存储延迟的方法

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软件学报 2005年第10期16卷 1833-1841页

作者：刘利李文龙陈彧李胜梅汤志忠清华大学计算机科学与技术系北京100084 Intel中国研究中心编译组北京100080

软件流水是一种重要的指令调度技术,它通过同时执行来自不同循环体的指令来加快循环的执行速度.随着处理机运行速度的逐渐提高,存储访问延迟成为性能提高的瓶颈.为了减轻存储系统影响,软件流水结合了一些存储优化技术,通过隐藏存储延迟... 详细信息

软件流水是一种重要的指令调度技术,它通过同时执行来自不同循环体的指令来加快循环的执行速度.随着处理机运行速度的逐渐提高,存储访问延迟成为性能提高的瓶颈.为了减轻存储系统影响,软件流水结合了一些存储优化技术,通过隐藏存储延迟来提高性能.提出了一种延迟可预测的模调度算法(foresightedLatencymoduloscheduling,简称FLMS),它根据循环的特点来确定load指令延迟.实验结果表明,FLMS算法减少了阻塞时间,提高了程序性能.

关键词：软件流水模调度涪储延迟 FLMS(foresighted Latency modulo scheduling)

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Systems biology applications to study mechanisms of human immunodeficiency virus Latency and reactivation

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World Journal of Clinical Infectious Diseases 2016年第2期6卷 6-21页

作者： Cory H White Bastiaan Moesker Angela Ciuffi Nadejda Beliakova-Bethell Graduate Program in Bioinformatics and Systems Biology University of California San Diego San Diego VA Medical Center and Veterans Medical Research Foundation Clinical and Experimental Sciences Faculty of Medicine University of Southampton Institute of Microbiology University Hospital of Lausanne (CHUV) and University of Lausanne Department of Medicine Univer-sity of California San Diego

Eradication of human immunodeficiency virus(HIV) in infected individuals is currently not possible because of the presence of the persistent cellular reservoir of latent infection. The identification of HIV Latency biomarkers and a better understanding of the molecular mechanisms contributing to regulation of HIV expression might provide essential tools to eliminate these latently infected cells. This review aims at summarizing gene expression profiling and systems biology applications to studies of HIV Latency and eradication. Studies comparing gene expression in latently infected and uninfected cells identify candidate Latency biomarkers and novel mechanisms of Latency control. Studies that profiled gene expression changes induced by existing Latency reversing agents(LRAs) highlight uniting themes driving HIV reactivation and novel mechanisms that contribute to regulation of HIV expression by different LRAs. Among the reviewed gene expression studies, the common approaches included identification of differentially expressed genes and gene functional category assessment. Integration of transcriptomic data with other biological data types is presently scarce, and the field would benefit from increased adoption of these methods in future studies. In addition, designing prospective studies that use the same methods of data acquisition and statistical analyses will facilitate a more reliableidentification of Latency biomarkers using different model systems and the comparison of the effects of different LRAs on host factors with a role in HIV reactivation. The results from such studies would have the potential to significantly impact the process by which candidate drugs are selected and combined for future evaluations and advancement to clinical trials.

关键词： Gene expression Microarrays RNA-Seq Systems biology Human immunodeficiency virus Viral Latency Disease eradication Biomarkers Molecular mechanisms Latency reversing agents

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Method for Latency Measurement of Visual Feedback-Based Master–Slave Minimally Invasive Surgical Robot

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Transactions of Tianjin University 2018年第4期24卷 375-386页

作者： Jinhua Li Jingchao Shen He Su Shuxin Wang Jianmin Li School of Mechanical Engineering Tianjin UniversityTianjin 300350China College of Computer and Control Engineering Nankai UniversityTianjin 300350China Key Laboratory for Mechanism Theory and Equipment Design of Ministry of

To measure the Latency between human motion stimulation and stereo image display response in a visual feedback-based minimally invasive surgical(MIS) robotic system,a method was proposed by comparing the orientations of input and output events through image-processing technology. This method used a black bar to keep pace with the measured joint rotating at a number of speeds. During tests,an external camera was placed in front of the apparatus with a proper visual field,so that it can simultaneously view orientations of both bars fixed on the corresponding joints. After quantitatively analyzing the accuracy of the proposed measurement method,the method was applied to a visual feedback-based master–slave robotic system with two-degrees-of-freedom. Experimental results show that the Latency of the overall system was approximately 250 ms,and the opposite clearance of the measured joint was in the range of 1.7°–1.9°.

关键词： Minimally invasive surgical(MIS)robot Latency measurement Real time Visual feedback

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