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MilkyWay-2 supercomputer： system and application

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Frontiers of Computer Science 2014年第3期8卷 345-356页

作者： xiangke liao Liquan XIAO Canqun YANG Yutong LU Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha 410073 China College of Computer National University of Defense Technology Changsha 410073 China

On June 17, 2013, MilkyWay-2 （Tianhe-2） supercomputer was crowned as the fastest supercomputer in the world on the 41th TOP500 list. This paper provides an overview of the MilkyWay-2 project and describes the design of hardware and software systems. The key architecture features of MilkyWay-2 are highlighted, including neo-heterogeneous compute nodes integrating commodity- off-the-shelf processors and accelerators that share similar instruction set architecture, powerful networks that employ proprietary interconnection chips to support the massively parallel message-passing communications, proprietary 16- core processor designed for scientific computing, efficient software stacks that provide high performance file system, emerging programming model for heterogeneous systems, and intelligent system administration. We perform extensive evaluation with wide-ranging applications from LINPACK and Graph500 benchmarks to massively parallel software deployed in the system.

关键词： MilkyWay-2 supercomputer petaflops computing neo-heterogeneous architecture interconnect network heterogeneous programing model system management benchmark optimization performance evaluation

Evolutionary Multi-Tasking Optimization for High-Efficiency Time Series Data Clustering

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Tsinghua Science and Technology 2024年第2期29卷 343-355页

作者： Rui Wang Wenhua Li Kaili Shen Tao Zhang xiangke liao Xiangjiang Laboratory Changsha 410205China College of Systems Engineering National University of Defense TechnologyChangsha 410073China Ant Group Co. Ltd.Hangzhou 310000China College of Computer Science and Technology NUDTChangsha 410073China

Time series clustering is a challenging problem due to the large-volume,high-dimensional,and warping characteristics of time series *** clustering methods often use a single criterion or distance measure,which may not capture all the features of the *** paper proposes a novel method for time series clustering based on evolutionary multi-tasking optimization,termed i-MFEA,which uses an improved multifactorial evolutionary algorithm to optimize multiple clustering tasks simultaneously,each with a different validity index or distance ***,i-MFEA can produce diverse and robust clustering solutions that satisfy various preferences of *** on two artificial datasets show that i-MFEA outperforms single-objective evolutionary algorithms and traditional clustering methods in terms of convergence speed and clustering *** paper also discusses how i-MFEA can address two long-standing issues in time series clustering:the choice of appropriate similarity measure and the number of clusters.

关键词： time series clustering evolutionary multi-tasking multifactorial optimization clustering validity index distance measure

RTS-PGATS based approach for data-intensive scheduling in data grids

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Frontiers of Computer Science 2011年第4期5卷 513-525页

作者： Kenli LI Zhao TONG Dan LIU Teklay TESFAZGHI xiangke liao College of Information Science and Engineering Hunan University Changsha 410082 China Computer School National University of Defense Technology Changsha 410072 China

Grid computing is the combination of com- puter resources in a loosely coupled, heterogeneous, and geographically dispersed environment. Grid data are the data used in grid computing, which consists of large-scale data-intensive applications, producing and consuming huge amounts of data, distributed across a large number of machines. Data grid computing composes sets of independent tasks each of which require massive distributed data sets that may each be replicated on different resources. To reduce the completion time of the application and improve the performance of the grid, appropriate computing resources should be selected to execute the tasks and appropriate storage resources selected to serve the files required by the tasks. So the problem can be broken into two sub-problems： selection of storage resources and assignment of tasks to computing resources. This paper proposes a scheduler, which is broken into three parts that can run in parallel and uses both parallel tabu search and a parallel genetic algorithm. Finally, the proposed algorithm is evaluated by comparing it with other related algorithms, which target minimizing makespan. Simulation results show that the proposed approach can be a good choice for scheduling large data grid applications.

关键词： data grid task scheduling tabu search,genetic algorithms parallelism

Leach： an automatic learning cache for inline primary deduplication system

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Frontiers of Computer Science 2014年第2期8卷 175-183页

作者： Bin LIN Shanshan LI xiangke liao Jing ZHANG Xiaodong LIU School of Computer National University of Defense Technology Changsha 410073 China

Deduplication technology has been increasingly used to reduce storage costs. Though it has been successfully applied to backup and archival systems, existing techniques can hardly be deployed in primary storage systems due to the associated latency cost of detecting duplicated data, where every unit has to be checked against a substantially large fin- gerprint index before it is written. In this paper we introduce Leach, for inline primary storage, a self-learning in-memory fingerprints cache to reduce the writing cost in deduplica- tion system. Leach is motivated by the characteristics of real- world I/O workloads： highly data skew exist in the access patterns of duplicated data. Leach adopts a splay tree to or- ganize the on-disk fingerprint index, automatically learns the access patterns and maintains hot working sets in cache mem- ory, with a goal to service a majority of duplicated data de- tection. Leveraging the working set property, Leach provides optimization to reduce the cost of splay operations on the fin- gerprint index and cache updates. In comprehensive experi- ments on several real-world datasets, Leach outperforms con- ventional LRU （least recently used） cache policy by reducing the number of cache misses, and significantly improves write performance without great impact to cache hits.

关键词： deduplication duplicate detection splay tree,cache

HTDcr:a job execution framework for high-throughput computing on supercomputers

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Science China(Information Sciences) 2024年第1期67卷 69-85页

作者： Jiazhi JIANG Dan HUANG Hu CHEN Yutong LU xiangke liao School of Computer Science and Engineering Sun Yat-sen University School of Software Engineering South China University of Technology

High-throughput computing(HTC) is a computing paradigm that aims to accomplish jobs by easily breaking them into smaller,independent ***,it requires a large amount of computing power for a long *** existing HTC frameworks are job-oriented without support for coscheduling with hardware architecture and task-level ***,most of the frameworks reach a limited scale,and their usability needs further ***,we present HTDcr,a job execution framework for the HTC on *** study aims to improve the throughput,task dispatching,and usability of the *** detail,the throughput optimizations include a sophisticated designed task management system,a hierarchical scheduler,and the co-optimization of the task-scheduling strategy with the application and hardware *** optimizations for usability include a programable execution workflow,mechanisms for more robust and reliable service qualities,and a fine-grained resource allocation system for the colocation of multiple *** to our evaluations,HTDcr can achieve outstanding scalability and high throughput on large-scale clusters for the HTC *** evaluate HTDcr with several microbenchmarks and real-world applications on Tianhe-2 and Sunway TaihuLight to demonstrate its effects on existing design *** instance,the task scheduling for two real-world applications integrated with the application and hardware characteristics achieves 1.7× and 1.9× speedups over the basic task-scheduling strategy.

关键词： high-throughput computing supercomputer task scheduling middleware password guessing

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LCCFS: a lightweight distributed file system for cloud computing without journaling and metadata services

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Science China(Information Sciences) 2019年第7期62卷 142-155页

作者： Li WANG Jingling XUE xiangke liao Yunchuan WEN Min CHEN School of Computer Science and Technology National University of Defense Technology School of Computer Science and Engineering University of New South Wales

The major usage of a file system integrated with a cloud computing platform is to provide the storage for VM(virtual machine) instances. Distributed file systems, especially those implemented on top of object storage have many potential advantages over traditional local file systems for VM instance storage. In this paper, we make an investigation in the requirements imposed on a file system in cloud computing scenario,and claim that the implementation of a file system for VM instance storage could be reasonably simplified. We demonstrate that on top of an object storage with simple object-granularity transaction support, a lightweight distributed file system, which requires neither journaling nor dedicated metadata services, can be developed for cloud computing. We have implemented such a distributed file system, called LCCFS(lightweight cloud computing file system), based on the RADOS(reliable autonomic distributed object storage) object *** experimental results show that for the main workloads in cloud computing, LCCFS achieves almost the same or slightly higher performance than CephFS(ceph filesystem), another published distributed file system based on RADOS. Compared to CephFS, LCCFS has only one tenth of its LOCs(lines of code). This theoretical simplicity makes it easy to implement LCCFS correctly and stably by avoiding the sheer design and implementation complexity behind CephFS, thereby making LCCFS a promising candidate in the cloud computing production environment.

关键词： cloud computing distributed file system journaling metadata service garbage collection

A survey of script learning

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Frontiers of Information Technology & Electronic Engineering 2021年第3期22卷 341-373页

作者： Yi HAN Linbo QIAO Jianming ZHENG Hefeng WU Dongsheng LI xiangke liao Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense TechnologyChangsha 410000China Science and Technology on Information Systems Engineering Laboratory National University of Defense TechnologyChangsha 410000China School of Data and Computer Science Sun Yat-sen UniversityGuangzhou 510006China

Script is the structured knowledge representation of prototypical real-life event *** the commonsense knowledge inside the script can be helpful for machines in understanding natural language and drawing commonsensible *** learning is an interesting and promising research direction,in which a trained script learning system can process narrative texts to capture script knowledge and draw ***,there are currently no survey articles on script learning,so we are providing this comprehensive survey to deeply investigate the standard framework and the major research topics on script *** research field contains three main topics:event representations,script learning models,and evaluation *** each topic,we systematically summarize and categorize the existing script learning systems,and carefully analyze and compare the advantages and disadvantages of the representative *** also discuss the current state of the research and possible future directions.

关键词： Script learning Natural language processing Commonsense knowledge modeling Event reasoning

He Match: A redundancy layout placement scheme for erasure-coded storages in practical heterogeneous failure patterns

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Science China(Information Sciences) 2015年第6期58卷 171-181页

作者： ZHANG Jing LI ShanShan liao xiangke PENG ShaoLiang LIU XiaoDong JIA ZhouYang School of Computer Science and Technology National University of Defence Technology

Erasure codes are widely used in storage systems for providing data reliability due to the advantage of high storage efficiency, while the access efficiency becomes the main shortcoming because of the extra data retrieve and decoding for accessing unavailable data. Most existing work designs erasure codes based on the ideal failure pattern where all storage nodes fail at the same rate. However in practice, the physical storage nodes fail at different rates due to the heterogeneous hardware, topologies and application behaviors. In this paper,we consider the heterogeneous failure pattern and analyze how the failure pattern impacts the overall access efficiency and reliability of erasure-coded storage systems. We propose He Match, a redundancy layout placement scheme in practical heterogeneous failure pattern for erasure-coded storage access efficiency. Specifically, we first study how the heterogeneous failure pattern impacts the access efficiency and propose a general model based on the Tanner graph to evaluate and predict the access efficiency in specific failure pattern and redundancy ***, we propose the redundancy layout placement scheme, which matches the redundancy layout with the physical storage nodes in practical heterogeneous failure patterns based on the evaluation and prediction from our model. The experimental results demonstrate that the model we propose accurately evaluates the access efficiency, and He Match saves unavailable data access cost by up to 20% and improves the system reliability as well.

关键词： network storage erasure-coded storage access efficiency redundancy placement heterogeneous failure pattern

Enhancement of cooperation between file systems and applications — VFS extensions for optimized performance

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Science China(Information Sciences) 2015年第9期58卷 46-55页

作者： WANG Li liao xiangke XUE JingLing WEIL Sage WEN YunChuan YANG XueJun School of Computer Science and Technology National University of Defense Technology School of Computer Science and Engineering University of New South Wales

Modern operating systems incorporate an abstract layer called Virtual File System(VFS), which is positioned between user applications and real file systems to hide the differences of various file systems and to expose generic application interfaces for requesting file system services. However, VFS sometimes does not give applications an opportunity to pass information to file systems to help them make correct optimization decisions. In this paper, we review the Linux VFS, discuss its deficiencies and propose several extensions to allow applications to cooperate with the file systems more efficiently. We introduce simple prefetching interfaces and advisory flags to allow applications to communicate application-related semantics to VFS and/or the underlying file systems. These suggestions, which neither affect the semantics of applications nor modify their programming models, not only lead to simple VFS/file systems but also guide them to make correct performance-related decisions, if required. We demonstrate that these interfaces and flags are also easy to implement and can boost application performance by up to 4.29 X.

关键词： virtual file system metadata cache dentry cache page cache page readahead