基于遗传算法的网格任务调度研究

本文针对网格任务调度中存在资源提供者和网格用户对网格环境需求之间的矛盾,提出了一种新的基于遗传算法的任务调度策略,本策略可以通过调整适应度函数中参数的取值来解决上述矛盾,并采用Gridsim模拟器进行了仿真试验,结果表明,该方案更适合网格环境中的任务调度。     

基于遗传算法的自适应网格任务调度方法

文章提出了一种以资源代理为基础的任务调度方法—GMBSA,该方法先对任务执行时间进行预测,然后运用遗传算法结合多队列Backfilling方法进行任务调度,达到最小化任务执行时间(MinimumExecutionTime)的要求,最终实现网格资源的优化分配。试验中采用Simgrid任务调度模拟器对GMBSA的性能进行了测试,并比较了轻重负载情况下GMBSA,多队列Backfilling和FCFS三种调度方案的性能差异。     

基于价格激励机制的网格调度算法模拟

基于网格计算市场模型的网格任务调度借鉴人类社会竞争的市场调节机制,根据用户的经济需求进行资源管理与任务调度,使资源提供者和资源消费者都能实现各自的经济利益。采用基于离散事件的网格模拟器GridSim模拟一个具体的网格环境,并模拟实现了基于网格资源价格激励机制的任务调度算法,最后通过程序运行结果验证该调度算法的有效性以及不足之处。     

关于网格模拟器的研究

网格将广域分布的各种资源有效聚合和共享,并以统一的方式向用户提供服务。网格模拟器是一种对真实网格进行模拟的工具,是研究网格环境中资源管理和任务调度策略优化、改进的重要工具。文中分别对Bricks,MicroGrid,Cas-Sim,GridSim,SimGrid和GangSim进行了分析,论述了这些模拟器的应用领域、优势以及不足,最后指出了当前网格模拟器的局限性和发展趋势,可以为网格研究人员和网格模拟器设计者及应用者提供一些便利。     

关于网格模拟器的研究

网格将广域分布的各种资源有效聚合和共享,并以统一的方式向用户提供服务。网格模拟器是一种对真实网格进行模拟的工具,是研究网格环境中资源管理和任务调度策略优化、改进的重要工具。文中分别对Bricks,MicroGrid,Cas-Sim,GridSim,SimGrid和GangSim进行了分析,论述了这些模拟器的应用领域、优势以及不足,最后指出了当前网格模拟器的局限性和发展趋势,可以为网格研究人员和网格模拟器设计者及应用者提供一些便利。     

基于资源预测的网格任务调度模型

跨越虚拟组织中多个域(或集群)的网格任务调度由于资源的不确定性（如动态性和异构性）而成为网格应用中亟待解决的问题。提出了一种有效的基于资源预测的网格任务调度模型——RPTS,该模型利用加权最小二乘方法进行参数估计的自回归滑动平均(ARMA)预测方法对网格环境下的主机负载进行预测。利用上述资源预测结果和一类数据并行性网格任务的建模结果,对它们进行预处理、匹配并调度执行。RPTS充分考虑了网格环境下资源的动态性和异构性,为解决网格环境下任务调度问题提供了一种较好的方法。与其他一些网格任务调度方法进行了一系列的仿真实验,结果表明RPTS模型具有任务执行时间最短和稳定性较好的特点。     

基于事件图模型的网格调度模拟

由于网格环境的复杂、动态和自治性等特点,研究网格任务调度时,高性能的网格模拟器是不可或缺的.该文引入了一个基于事件图模型的高性能模拟器HyperSim,介绍了HyperSim的特点,通过对比其他模拟器说明使用HyperSim的理由.为了优化模拟速度,提出了网格任务调度的事件图模型,并给出了在HyperSim上的实现过程.最后,通过实验证明了HyperSim在运行速度和性能方面的优势,并用其模拟了两种经典调度算法的实现,根据模拟结果对比了算法的性能.     

基于Simgrid的网格任务调度模拟

随着Internet的发展,网格计算技术逐渐成为新的研究领域。网格系统由大量异构资源组成,具有复杂、动态和自治等特点。高效的调度策略或算法可以充分利用网格系统的处理能力,从而提高应用程序的性能。在网格任务调度的研究中,没有必要使用实际系统验证算法的正确性及性能,而往往采用模拟器完成这一工作,选用正确的模拟器对研究起着事半功倍的作用。首先介绍了Simgrid的特点,并通过对比其他模拟器说明使用Simgrid的理由。然后,根据目前网格系统的使用模式,提出了由多个数据传输和计算两部分组成的网格元任务形式,作为网格调度的最小单位。最后,根据这种任务组成,改进了一些经典的任务调度算法。论文详细介绍了改进的方法,并通过模拟结果对比了新旧算法的性能。     

一种数据网格副本管理仿真软件

副本管理成为影响数据网格性能的主要因素之一,研究高效的副本管理算法大都依赖于对数据网格副本管理进行仿真.介绍了一种数据网格副本管理仿真软件的设计与实现,并详细介绍了数据网格仿真的一些关键技术的解决方案,如任务调度、任务执行仿真.     

网格计算中任务调度算法的仿真研究

研究网格计算中任务调度优化问题,由于网格环境具有动态性、异构性等特点,对高效调试资源效率有影响,导致传统网格任务调度算法收敛速度慢、局部最优等缺陷,使网格任务调度效率低.为了提高网格任务调度效率,提出一种基于粒子群算法的任务调度模型.模型根据任务调度原理和粒子群算法特点,建立了网格任务调度的元任务模型和性能指标的数学模型,然后采用粒子群算法对该模型进行求解,提高资源利用率和任务执行效率.仿真结果表明,根据粒子群算法的任务调度策略,提高了任务调度的速度和效率,很好的解决网格任务调度中存在的难题.     

Enhancing list scheduling heuristics for dependent job scheduling in grid computing environments

Job scheduling plays a critical role in resource utilisation in a grid computing environment. The heterogeneity of grid resources adds some challenges to the work of job scheduling especially when jobs have dependencies which can be represented as Direct Acyclic Graphs (DAGs). Heuristics have been developed for job scheduling optimisation. This paper presents six heuristic enhancements—MMSTFT for minimising both makespan and task finish time, levelU for upward DAG levelling, TMWD for matching tasks with data, Slack for prioritising task scheduling based on slack time, LSlack for levelling the Slack heuristic, and NLPETS for non-levelling of performance effective task scheduling (PETS). The performance of LSlack is amongst the best heuristics evaluated (with BL and LMT). Additionally, heuristic enhancements MMSTS and TMWD can significantly improve the makespan of generated schedules. To facilitate performance evaluation, a DAG simulator is implemented which provides a set of tools for DAG job configuration, execution and monitoring. The components of the DAG simulator are also presented in this paper.     

基于GridSim的网格模拟框架设计与实现

设计并实现一个基于GridSim的网格模拟框架GSF,利用XML语言描述网格资源、用户、作业,提供网格调度接口。针对工作流作业定义工作流描述语言GSWDL,实现一个工作流模拟器WorkFlowEngine。模拟实验结果证明,GSF可以减少用户对GridSim的学习时间和难度,为研究者提供一个易用、可扩展的网格模拟环境。     

Enhanced Dynamic Hierarchical Replication and Weighted Scheduling Strategy in Data Grid

The Data Grid provides massive aggregated computing resources and distributed storage space to deal with data-intensive applications. Due to the limitation of available resources in the grid as well as production of large volumes of data, efficient use of the Grid resources becomes an important challenge. Data replication is a key optimization technique for reducing access latency and managing large data by storing data in a wise manner. Effective scheduling in the Grid can reduce the amount of data transferred among nodes by submitting a job to a node where most of the requested data files are available. In this paper two strategies are proposed, first a novel job scheduling strategy called Weighted Scheduling Strategy (WSS) that uses hierarchical scheduling to reduce the search time for an appropriate computing node. It considers the number of jobs waiting in a queue, the location of the required data for the job and the computing capacity of the sites Second, a dynamic data replication strategy, called Enhanced Dynamic Hierarchical Replication (EDHR) that improves file access time. This strategy is an enhanced version of the Dynamic Hierarchical Replication strategy. It uses an economic model for file deletion when there is not enough space for the replica. The economic model is based on the future value of a data file. Best replica placement plays an important role for obtaining maximum benefit from replication as well as reducing storage cost and mean job execution time. So, it is considered in this paper. The proposed strategies are implemented by OptorSim, the European Data Grid simulator. Experiment results show that the proposed strategies achieve better performance by minimizing the data access time and avoiding unnecessary replication.     

An energy-efficient reliable grid scheduling model using NSGA-II

Job scheduling in computational grid is a complex problem and various heuristics and meta-heuristics have been proposed for the same. These approaches usually optimize specific characteristic parameters while allocating the jobs on the grid resources. Many a times, it is desired to optimize multiple parameters during job scheduling. Non-dominated sorting genetic algorithm (NSGA-II) has been observed to be the best meta-heuristic to solve such multi-objective optimization problem. The proposed work applies NSGA-II for job scheduling in computational grid with three conflicting objectives: maximizing reliability of the system for job allocation, minimizing energy consumption and balancing the load on the system. Performance study of the proposed model is done by simulating it on some real data. The result indicates that the proposed model performs well with multiple objectives.     

基于OPNET的局部网格任务调度平台设计

在充分考虑网格动态性和异构性的前提下,采用模块化设计方法,在OPNET环境下构建了一个局部网格任务调度仿真平台。在该平台上,比较了SF, LF, FCFS, EDF等网格任务调度算法。仿真实验结果表明调度算法运行良好,该网格仿真平台提供了一个通用的、模块化、可扩展的网格任务调度模拟环境,能够较好地满足网格任务调度要求。     

信任驱动的网格作业调度遗传算法

作业调度是网格计算的关键技术之一.近年来,人们将信任机制融入到作业调度算法中,以满足作业调度对网格服务质量提出的需求.根据一信任模型,设计了求解基于该信任模型的遗传算法,该算法在保持种群多样性的同时,提高了局部搜索能力.仿真结果表明,该算法可以获得较好的调度结果,且收敛速度快.     

基于QoS效益函数的网格任务调度算法

在网格环境中,任务调度是一个非常复杂、重要而且具有挑战性的问题.使用市场经济的概念来构建和管理网格资源是一种较好的方式,而DBC算法是计算经济模式下比较流行的一套调度算法.本文在现有算法的研究基础上,提出一种基于效益函数的改进的网格任务调度算法,并采用GridSim 模拟器对相关算法进行仿真模拟实验和比较.实验结果表明,本文提出的调度算法在任务完成率、实际使用时间、实际使用费用这三方面相对于现有的算法在综合性能上有一定的提高.     

Performance and energy aware scheduling simulator for HPC: evaluating different resource selection methods

Today, in an energy‐aware society, job scheduling is becoming an important task for computer engineers and system analysts that may lead to a performance per Watt trade‐off of computing infrastructures. Thus, new algorithms, and a simulator of computing environments, may help information and communications technology and data center managers to make decisions with a solid experimental basis. There are several simulators that try to address performance and, somehow, estimate energy consumption, but there are none in which the energy model is based on benchmark data that have been countersigned by independent bodies such as the Standard Performance Evaluation Corporation. This is the reason why we have implemented a performance and energy‐aware scheduling (PEAS) simulator for high‐performance computing. Furthermore, to evaluate the simulator, we propose an implementation of the non‐dominated sorting genetic algorithm‐II (NSGA‐II) algorithm, a fast and elitist multiobjective genetic algorithm, for the resource selection. With the help of the PEAS simulator, we have studied if it is possible to provide an intelligent job allocation policy that may be able to save energy and time without compromising performance. The results of our simulations show a great improvement in response time and power consumption. In most of the cases, NSGA‐II performs better than other ‘intelligent’ algorithms like multiobjective heterogeneous earliest finish time and clearly outperforms the first‐fit algorithm. We demonstrate the usefulness of the simulator for this type of studies and conclude that the superior behavior of multiobjective algorithms makes them recommended for use in modern scheduling systems. Copyright © 2015 John Wiley & Sons, Ltd.