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A framework for modelling and simulating data flows in distributed computing systems

IEEE TRANSACTIONS ON NUCLEAR SCIENCE 1998年第4期45卷 1951-1957页

作者： von Praun, C CERN CH-1211 Geneva 23 Switzerland

This paper introduces a framework for modelling and simulating the behaviour of distributed computing systems. The framework comprises both means for abstract modelling and an implementation that allows the evaluation of abstract models by means of discrete event simulation. The basic characteristics of distributed computing systems used for physics data processing at CERN are presented, motivating the purpose and need for modelling and simulation. As an example, the central data recording system of a current High-Energy Physics experiment is introduced. The modelling framework provides concepts to structure relevant state information of a system. The most important factor to set up the structure of components encapsulating state information is thereby given by dynamic aspects of the system, i.e. by identified data flows. Traditional approaches to modelling often tend to focus purely on static, architectural system aspects. All abstract concepts will be motivated and demonstrated using an example. Results of the simulation are compared to figures measured during real system operation, rating the proposed framework and its underlying modelling approach.

关键词： Frameworks simulated data Operating systems CERN distributed computing system simulating Modeling

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Optimal task allocation and hardware redundancy policies in distributed computing systems

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2003年第2期147卷 430-447页

作者： Hsieh, CC Natl Cheng Kung Univ Dept Ind Management Sci Tainan 70101 Taiwan

A distributed computing system (DCS) in general consists of processing nodes, communication channels, and tasks. Achieving a reliable DCS thus comprises three parts: the realization of reliable task processing, reliable communication among processing nodes, and a good task allocation strategy. In this study, we examine the relationship between system cost and system reliability in a cycle-free hardware-redundant DCS where multiple processors are available at each processing node and multiple communication links are available at each communication channel. Intuitively, higher hardware redundancy leads to higher system reliability which results in the reduction of communication cost. Such an endowment of hardware redundancy, however, incurs higher hardware operating cost. A unified model of system cost is therefore developed in this study that is a complex function of task allocation and hardware redundancy policies, and a hybrid genetic algorithm (HGA) based on genetic algorithms and a local search procedure is proposed to seek the optimal task allocation and hardware redundancy policies. The proposed algorithm is tested on randomly generated DCSs and compared with a simple genetic algorithm (SGA). The simulation results show that the HGA gives higher solution quality in less computational time than the SGA. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： distributed computing system hardware redundancy genetic algorithms system reliability

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Reliability and cost optimization in distributed computing systems

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COMPUTERS & OPERATIONS RESEARCH 2003年第8期30卷 1103-1119页

作者： Hsieh, CC Hsieh, YC Natl Cheng Kung Univ Dept Ind Management & Sci Tainan 70101 Taiwan

The reliability of the communication network and its processing units and the strategy of task allocation are essential in determining the system reliability of a distributed computing system. Reliability of such systems can be improved by endowing resource redundancy or the use of highly reliable components. In this paper, we develop a relationship between system cost and hardware redundancy levels, assuming cycle-free distributed computing systems. Based on the derived relationship, we propose a hybrid heuristic which combines genetic algorithms and the steepest decent method to seek the optimal task allocation and hardware redundancy policies such that system cost is minimized.

关键词： distributed computing system hardware redundancy system reliability

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STATIC TASK ALLOCATION OF CONCURRENT PROGRAMS FOR distributed computing systemS WITH PROCESSOR AND RESOURCE HETEROGENEITY

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PARALLEL computing 1994年第6期20卷 835-851页

作者： SELVAKUMAR, S MURTHY, CSR INDIAN INST TECHNOL DEPT COMP SCI & ENGNMADRAS 600036TAMIL NADUINDIA UNIV MASSACHUSETTS DEPT COMP SCIAMHERSTMA 01003

In this paper, we investigate the problem of static task allocation of concurrent programs for distributed computing systems with processor and resource heterogeneity, i.e. given a set of concurrent communicating modules and a two processor distributed computing system, in which processors may have differing speeds and each processor may have certain resources not available with the other processor (i.e. unique resources), to which processor should each module be assigned so as to minimize the completion time? This task allocation problem is NP-hard and hence, we provide an efficient heuristic algorithm for obtaining satisfactory suboptimal solution to it in a reasonable amount of computation time and demonstrate the effectiveness of our algorithm with simulation studies. Our algorithm works by constructing an augmented task graph and taking a load balanced mincut on it and has a time complexity of O((m + u)2) where m is the number of concurrent communicating modules and u is the total number of unique resources in the two processor system. Finally, we extend our heuristic algorithm to solve the problem of static task allocation of concurrent programs to an n processor distributed computing system with processor and resource heterogeneity.

关键词： distributed computing system TASK GRAPH TASK ALLOCATION RESOURCE ALLOCATION HEURISTICS

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EFFECTS OF RESPONSE AND STABILITY ON SCHEDULING IN distributed computing systemS

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IEEE TRANSACTIONS ON SOFTWARE ENGINEERING 1988年第11期14卷 1578-1588页

作者： CASAVANT, TL KUHL, JG UNIV IOWA DEPT ELECT & COMP ENGNIOWA CITYIA 52242

An examination is made of the effects of response and stability on scheduling algorithms for general-purpose distributed computing systems. Response characterizes the time required, following a perturbation in the system state, to reach a new equilibrium state. Stability is a measure of the ability of a mechanism to detect when the effects of further actions will not improve the system state as defined by a user-defined objective. These results have implications for distributed computations in general. Analysis is based on formal communicating finite automata models of two distinct approaches to the scheduling problem, each using the objective of global optimal load balancing. The results indicate that absolute stability is not always necessary in dynamic systems for the same reasons that relatively small amounts of instability are tolerated in the design of analog control systems. It is shown that response is a very important first-order metric of dynamic scheduling behavior, and that response and stability are related.

关键词： Load balancing analog controls Scheduling algorithms Dynamic systems absolute stability distributed computing system perturbation

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ON THE NUMBER OF ACCEPTABLE TASK ASSIGNMENTS IN distributed computing systemS

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IEEE TRANSACTIONS ON COMPUTERS 1990年第1期39卷 99-110页

作者： SHIN, KG CHEN, MS IBM CORP THOMAS J WATSON RES CTRYORKTOWN HTSNY 10598

A distributed computing system and cooperating tasks can be represented by a processor graph Gp=(Vp, Ep) and a task graph GT=(VT, E T), respectively. An edge between a pair of nodes in GT represents the existence of direct communications between the two corresponding tasks. The maximal number of hops between two processors in Gp to which two adjacent tasks in GT are assigned is called dilation of that assignment. Characterization and use of the number of acceptable assignments for given GT and GP are treated. Assignments with the dilation less than or equal to one are considered. This dilation constraint represents a special case in which two adjacent tasks in GT must be assigned to either a single processor or two adjacent processors in Gp. For the case where N(GT, GP ) denotes the numbers of acceptable assignments under this constraint, N(GT, GP) are derived for arbitrary GT and GP , and a recursive expression is formulated for N(G T, GP) when GT is a tree. For some restricted cases, either closed-form or recursive-form expressions of N(GT, G P) are derived. The results on N(GT, GP) are extended to the completely general case, assignments with dilations greater than one, where two adjacent tasks in GT can be assigned to any two processors in GP which are not necessarily adjacent to each other

关键词： Hypertrophy Humulus distributed computing system direct communication Uniprocessor Neighbor Dilatation Less than or equal to PROCESSOR Religious Missions

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Service reliability modeling of distributed computing systems with virus epidemics

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APPLIED MATHEMATICAL MODELLING 2015年第18期39卷 5681-5692页

作者： Li, Yan-Fu Peng, Rui Ecole Cent Paris SUPELEC Paris France Univ Sci & Technol Beijing Dongling Sch Econ & Management Beijing 100083 Peoples R China

distributed computing (DC) system is widely implemented due to its low setup cost and high computational capability. However, it might be vulnerable to malicious attacks like computer virus due to its network structure. The service reliability, defined as the probability of fulfilling a task before a specified time, is an important metric of the quality of a DC system. This paper attempts to model and compute the service reliability for the DC system under virus epidemics. Firstly, the DC system architecture is modeled by an undirected graph whose nodes (i.e. computers) have a continuous-state model representing its computational capability. Then a set of epidemic differential equations are formulated and solved to obtain the state dynamics of each node under the virus epidemics. A universal generating function (UGF) based approach is proposed to calculate the service reliability of DC system. Numerical results show the effectiveness of the proposed method. The sensitivity analysis on the model parameters, the comparison with centralized computing system and the optimization of defense level parameter are also conducted. (C) 2015 Elsevier Inc. All rights reserved.

关键词： Service reliability distributed computing system Virus epidemics Continuous-state model Differential equations Universal generating function

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Stability of dynamic groups in distributed computing systems

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APPLIED MATHEMATICS AND COMPUTATION 1996年第2-3期74卷 223-248页

作者： Billard, EA Faculty of Computer Science and Engineering University of Aizu Aizu-Wakamatsu City 965-80 Japan

Large distributed computing systems provide the opportunity for the synergistic use of shared resources;an example model is computational ecosystems. However, as networks continue to expand, it is not obvious that all of the agents within a network should participate in one interacting set. Although smaller groups may forfeit potential synergy, they also avoid much of the complexity and overhead of coordination. The nature of the dynamics is complicated by the inherent delays in networks and the state update schemes applied by the agents. Large intelligent systems must provide for 1) the participation of agents in a smaller group and/or 2) the participation of agents in the systemwide group only a fraction of the time. Both of these behaviors are modeled by a system of differential equations with a discrete distribution of time delays. Stability analysis determines the boundaries for damped and persistent oscillations based on the average of the discrete time delays. In large systems, there is a fixed ratio between these boundaries: e pi/2. The results also show that stability improves with diversity in the delays.

关键词： Differential equations Behavior Delay Agents dynamic distributed computing system discrete-time delay Network Differential equations absorption of shock

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IMPROVED TASK-ALLOCATION ALGORITHMS TO MAXIMIZE RELIABILITY OF REDUNDANT distributed computing systemS

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IEEE TRANSACTIONS ON RELIABILITY 1995年第4期44卷 575-586页

作者： KARTIK, S MURTHY, CSR INDIAN INST TECHNOL DEPT COMP SCI & ENGN MADRAS 600036 TAMIL NADU INDIA

This paper considers the problem of finding an optimal & sub-optimal task-allocation (assign the processing node for each module of a task or program) in redundant distributed computing systems, with the goal of maximizing system-reliability (probability that the system completes the entire task successfully). Finding an optimal task-allocation is NP-hard in the strong sense. An efficient algorithm is presented for optimal task-allocation in a distributed computing system with level-2 redundancy. The algorithm, a) uses branch & bound with underestimates for reducing the average time complexity of optimal task-allocation computations, and b) reorders the list of modules to allow a subset of modules that does not intra-communicate to be assigned last, for further reduction in the computations of optimal task-allocation for maximizing reliability. An efficient heuristic algorithm is given which obtains sub-optimal solutions in a reasonable computation time. The performance of our algorithms is given over a wide range of parameters such as: number of modules, number of processing nodes, ratio of average execution cost to average communication cost, and connectivity of modules. The effectiveness of the optimal task-allocation algorithm is demonstrated by comparing it to a recent competing optimal task-allocation algorithm, for maximizing reliability. The performance of our algorithm improves very much when the difference between the number of modules and the connectivity increases. Our heuristic algorithm produced optimal solutions in 24% of the cases and found allocations within 1.5 times the optimal in about 86% of the cases.1

关键词： TASK ALLOCATION distributed computing system system RELIABILITY OPTIMALITY SEARCH TREE HEURISTIC

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ON THE DESIGN OF A distributed OPERATING system USING A HIGH-LEVEL distributed-PROGRAMMING LANGUAGE

MICROPROCESSING AND MICROPROGRAMMING

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MICROPROCESSING AND MICROPROGRAMMING 1982年第4期10卷 247-254页

作者： ARORA, RK SHARMA, NK Computer Centre Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India

A methodology to design a distributed operating system is presented. The advantage of using a high-level distributed programming language as a design, documentation, and implementation tool is illustrated.

关键词： distributed computing system distributed operating system distributed programming language

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