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Evaluating the impacts of hugepage on virtual machines

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Science China(Information Sciences) 2017年第1期60卷 35-50页

作者： Xiaolin WANG Taowei luo Jingyuan HU Zhenlin WANG yingwei luo School of Electronics Engineering and Computer Science Peking University Department of Computer Science Michigan Technological University

Modern applications often require a large amount of memory. Conventional 4KB pages lead to large page tables and thus exert high pressure on TLB address translations. This pressure is more prominent in a virtualized system, which adds an additional layer of address translation. Page walks due to TLB misses can result in a significant performance overhead. One effort in reducing this overhead is to use hugepage. Linux kernel has supported transparent hugepage since 2.6.38, which provides an alternate large page size. Generally,hugepage demonstrates better performance on address translations and page table modifications. This paper first analyzes the impact of hugepage on native system, and then, compares the impact of hugepage on different memory virtualization approaches: hardware-assisted paging(HAP), shadow paging, and *** observe that the current implementation of transparent hugepage is inefficient. It cannot exploit the full performance advantage of hugepages. Worse yet, the conservative strategy of transparent hugepage may conflict with existing OS functions, which can lead to performance degradation. So, we propose a new memory allocation strategy, alignment-based hugepage(ABH) that promotes hugepage allocations. We apply ABH to different paging modes in virtualized systems. The results show that the new allocation strategy can significantly reduce TLB misses and up to 90% page walk cycles due to TLB misses and thus improve the performance in real world applications.

关键词： hugepage memory management translation lookaside buffer virtualization performance

Dynamic cache partitioning based on hot page migration

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Frontiers of Computer Science 2012年第4期6卷 363-372页

作者： Xiaolin WANG Xiang WEN Yechen LI Zhenlin WANG yingwei luo Xiaoming LI Department of Computer Science Peking UniversityBeijing 100871China Department of Computer Science Michigan Technological UniversityHoughtonMI 49931USA The Shenzhen Key Lab for Cloud Computing Technology and Applications Peking University Shenzhen Graduate SchoolShenzhen 518055China

Static cache partitioning can reduce inter- application cache interference and improve the composite performance of a cache-polluted application and a cache- sensitive application when they run on cores that share the last level cache in the same multi-core processor. In a virtu- alized system, since different applications might run on dif- ferent virtual machines （VMs） in different time, it is inappli- cable to partition the cache statically in advance. This paper proposes a dynamic cache partitioning scheme that makes use of hot page detection and page migration to improve the com- posite performance of co-hosted virtual machines dynami- cally according to prior knowledge of cache-sensitive appli- cations. Experimental results show that the overhead of our page migration scheme is low, while in most cases, the com- posite performance is an improvement over free composition.

关键词： cache partitioning hot page migration dynamic cache partitioning virtualization virtual machine monitor

A survey of cloud resource management for complex engineering applications

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Frontiers of Computer Science 2016年第3期10卷 447-461页

作者： Haibao CHEN Song WU Hai JIN Wenguang CHEN Jidong ZHAI yingwei luo Xiaolin WANG Services Computing Technology and System Lab Cluster and Grid Computing LabSchool of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China Institute of High Performance Computing Tsinghua University Beijing 100084 China School of Electronics Engineering and Computer Science Peking University Beijing 100871 China School of Computer and Information Engineering Chuzhou University Chuzhou 239000 China

Traditionally, complex engineering applications （CEAs）, which consist of numerous components （software） and require a large amount of computing resources, usu- ally run in dedicated clusters or high performance computing （HPC） centers. Nowadays, Cloud computing system with the ability of providing massive computing resources and cus- tomizable execution environment is becoming an attractive option for CEAs. As a new type on Cloud applications, CEA also brings the challenges of dealing with Cloud resources. In this paper, we provide a comprehensive survey of Cloud resource management research for CEAs. The survey puts forward two important questions： 1） what are the main chal- lenges for CEAs to run in Clouds？ and 2） what are the prior research topics addressing these challenges？ We summarize and highlight the main challenges and prior research topics. Our work can be probably helpful to those scientists and en- gineers who are interested in running CEAs in Cloud envi- ronment.

关键词： Cloud computing complex engineering application resource management virtualization

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Learning to Combine Answer Boundary Detection and Answer Re-ranking for Phrase-Indexed Question Answering

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Chinese Journal of Electronics 2022年第5期31卷 938-948页

作者： WEN Liang SHI Haibo ZHANG Xiaodong SUN Xin WEI Xiaochi WANG Junfeng CHENG Zhicong YIN Dawei WANG Xiaolin luo yingwei WANG Houfeng Department of Computer Science and Technology Peking University Peng Cheng Laboratory Baidu Inc.

Phrase-indexed question answering(PIQA) seeks to improve the inference speed of question answering(QA) models by enforcing complete independence of the document encoder from the question encoder,and it shows that the constrained model can achieve significant efficiency at the cost of its accuracy. In this paper, we aim to build a model under the PIQA constraint while reducing its accuracy gap with the unconstrained QA models. We propose a novel framework —Ans DR,which consists of an answer boundary detector(Ans D)and an answer candidate ranker(Ans R). More specifically, Ans D is a QA model under the PIQA architecture and it is designed to identify the rough answer boundaries; and Ans R is a lightweight ranking model to finely rerank the potential candidates without losing the efficiency. We perform the extensive experiments on public datasets. The experimental results show that the proposed method achieves the state of the art on the PIQA task.

关键词： Real-time question answering Answer boundary detection Answer re-ranking Phrase-indexed question answering Answer span aware loss

Dynamic memory mapping delivers additional flexibility to virtual resource management

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Chinese Science Bulletin 2010年第26期55卷 3071-3071页

作者： WANG XiaoLin luo yingwei Department of Computer Science and Technology Peking University Beijing 100871 China

The Department of Computer Science and Technology, Peking University, Beijing, China, has shown that a novel Dynamic Memory Map-ping (DMM) model brings about additional flexibility to virtual resource management, leading to the feature-adjustable design of a virtual machine monitor (VMM). The study is reported in Issue 53 (June, 2010) of SCIENCE CHINA Information Sciences because of its signifi-cant research value.

关键词：内存映射资源管理虚拟资源活性计算机科学与技术北京大学监控功能信息科学

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QoS Analysis on Web Service Based Spatial Integration

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通讯和计算机（中英文版） 2005年第7期2卷 70-81页

作者： yingwei luo Xinpeng Liu Wenjun Wang Xiaolin Wang Zhuoqun Xu Department of Computer Science and Technology Peking Universityj Beifing 100871China

Web Service is a standard-based software technology. It sets service-oriented development, deployment and integration as its basic jumping-off place, and has become the primary publishing mechanism and organization framework in the environment of distributed computing and services in Internet. Currently, especially in distributed applications of large scaled spatial information, due to user"s strong dependence on data formats and platforms of certain GIS(Geographical Information Systems) manufacturer, there are obvious difficulty and complexity in inter-platform spatial information exchange and system development. In this paper, the concrete design and implementation of an integration and interoperation platform that aims to solve heterogeneity and on-line service for geographical information is presented first. This platform concentrates on implementation to shield heterogeneity among spatial data sources and services through a common spatial data transmission and exchange format-GML. In addition, QoS control for WebGIS Services of the integration and interoperation platform is expatiated from different aspects: cache mechanism, GML(Geography Markup Language) data compression, map on-line generation, etc.

关键词： Web Service SOAP, WSDL QoS Interoperation

Mapping Business Workflows onto Network Services Environment

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通讯和计算机（中英文版） 2005年第1期2卷 1-11,25页

作者： WANG Wenjun luo yingwei LIU Xinpeng WANG Xiaolin XU Zhuoqun Department of Computer Science and Technology Peking University Beijing 100871 China

Estimation of Reference Values for PFOS and PFOA in Human Biomonitoring and Relevance of Exposure among Family Members in China

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Journal of Environmental Protection 2012年第4期3卷 353-361页

作者： Wei Liu Guanghui Dong yingwei luo Li Liu Ziwei Cao Xiaona Li Yihe Jin School of Environmental Science and Technology Dalian University of Technology Key Laboratory of Industrial Ecology and Environmental Engineering Ministry of Education Dalian China School of Public Health China Medical University Shenyang China The first hospital of China medical university Shenyang China

The reference values of serum perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) concentrations were evaluated based on the human blood samples collected from Kashi, Xinjiang. And human serum samples of family members from Liaoning were evaluated for levels of PFOS and PFOA with the purpose to compare exposure pathways for family members. Among the 110 blood specimens from Kashi, the detection frequency of PFOS and PFOA was 93% and 6%, respectively. Reference values of serum PFOS, evaluated as the 90th percentiles of the concentrations, were determined to be 6.44 μg/L. Significant positive correlations were observed for serum levels of PFOS and PFOA among family members in Liaoning. Specially, stronger correlation between mother and offspring was observed than that between father and offspring. And stronger correlation of serum PFOS and PFOA levels was observed among fam- ily members in rural areas than those in big and small-medium cities. Difference in the association of serum PFOS and PFOA level among family members suggested that exposure in the outdoor and working environment of different oc- cupations should be evaluated. Present study provides reference values for exposure assessment in China and potential pathways of human exposure to PFOS and PFOA.

关键词： Perfluorinated Compounds Human Biomonitoring Reference Value Exposure Family Member

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面向服务的工作流分层映射模型

高技术通讯 2008年第9期18卷 921-927页

作者：罗英伟汪小林许卓群北京大学计算机科学与技术系北京100871

基于对面向服务的体系结构(SOA)下服务角色划分以及对当前分布式应用特征的分析,通过引入抽象资源和抽象服务的概念,提出了一个面向服务的将工作流划分为业务工作流(BWF)、抽象工作流(AWF)和执行工作流(EWF)的工作流映射模型。它将业务... 详细信息

基于对面向服务的体系结构(SOA)下服务角色划分以及对当前分布式应用特征的分析,通过引入抽象资源和抽象服务的概念,提出了一个面向服务的将工作流划分为业务工作流(BWF)、抽象工作流(AWF)和执行工作流(EWF)的工作流映射模型。它将业务工作流的部署、执行转换成两个映射——业务工作流到抽象服务工作流的映射和抽象服务工作流到执行服务工作流的映射。这一模型为当前 Internet 上基于 Web 服务和 Grid 服务的分布式应用提供了一种动态的组织、部署和执行方案。此外重点探讨了实现该模型下多层次工作流计算机辅助映射的应用模板技术,应用模板定义了各个抽象资源和抽象服务在特定应用任务中必须遵从的约束及必须提供的相关元数据。

关键词：服务环境抽象服务抽象资源工作流应用模板

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