A Cost Model for IaaS Clouds Based on Virtual Machine Energy Consumption

Cloud Computing has revolutionized the software, platform and infrastructure provisioning. Infrastructure-as-a-Service (IaaS) providers offer on-demand and configurable Virtual Machine (VMs) to tenants of cloud computing services. A key consolidation force that widespread IaaS deployment is the use of pay-as-you-go and pay-as-you-use cost models. In these models, a service price can be composed of two dimensions: the individual consumption, and a proportional value charged for service maintenance. A common practice for public providers is to dilute both capital and operational costs on predefined pricing sheets. In this context, we propose PSVE (Proportional-Shared Virtual Energy), a cost model for IaaS providers based on CPU energy consumption. Aligned with traditional commodity prices, PSVE is composed of two key elements: an individualized cost accounted from CPU usage of VMs (e.g., processing and networking), and a shared cost from common hypervisor management operations, proportionally distributed among VMs.     

Online Bi-Objective Scheduling for IaaS Clouds Ensuring Quality of Service

This paper focuses on a bi-objective experimental evaluation of online scheduling in the Infrastructure as a Service model of Cloud computing regarding income and power consumption objectives. In this model, customers have the choice between different service levels. Each service level is associated with a price per unit of job execution time, and a slack factor that determines the maximal time span to deliver the requested amount of computing resources. The system, via the scheduling algorithms, is responsible to guarantee the corresponding quality of service for all accepted jobs. Since we do not consider any optimistic scheduling approach, a job cannot be accepted if its service guarantee will not be observed assuming that all accepted jobs receive the requested resources. In this article, we analyze several scheduling algorithms with different cloud configurations and workloads, considering the maximization of the provider income and minimization of the total power consumption of a schedule. We distinguish algorithms depending on the type and amount of information they require: knowledge free, energy-aware, and speed-aware. First, to provide effective guidance in choosing a good strategy, we present a joint analysis of two conflicting goals based on the degradation in performance. The study addresses the behavior of each strategy under each metric. We assess the performance of different scheduling algorithms by determining a set of non-dominated solutions that approximate the Pareto optimal set. We use a set coverage metric to compare the scheduling algorithms in terms of Pareto dominance. We claim that a rather simple scheduling approach can provide the best energy and income trade-offs. This scheduling algorithm performs well in different scenarios with a variety of workloads and cloud configurations.     

云虚拟机资源分配的效用最大化模型

随着云计算和虚拟化技术的发展,为云资源管理提供了一种更高层次的调度选择:一个作业不再只能分配到一台物理机上,而是可将一台或多台物理机的计算资源虚拟化成一台虚拟机来运行该作业.根据作业需要,高效分配定量的物理资源放置虚拟机,是决定云系统性能的关键因素,即云资源调度问题实质就是一个虚拟机和物理机之间的映射问题.文中借鉴网络效用最大化模型,提出了一种云资源调度模型——云效用最大化(Cloud Utility Maximization,CUM)模型,与传统调度模型相比,目标函数不再是最小化最大完工时间,而是以达到效用最大为调度目标,可以充分提高用户的满意程度.通过求解CUM优化问题得到最优的虚拟机和物理机映射关系.设计了针对该模型的分解优化算法——简化次梯度算法求解拉格朗日对偶问题,证明了该算法可以获得原始模型问题的最优解.仿真实验表明算法可行且具有良好的收敛特性,并给出了CUM模型在真实云环境下的应用场景.     

CPicker: Leveraging Performance-Equivalent Configurations to Improve Data Center Energy Efficiency

The poor energy proportionality of server is seen as the principal source for low energy efficiency of modern data centers. We find that different resource configurations of an application lead to similar performance, but have distinct energy consumption. We call this phenomenon as “performance-equivalent resource configurations (PERC)”, and its performance range is called equivalent region (ER). Based on PERC, one basic idea for improving energy efficiency is to select the most efficient configuration from PERC for each application. However, it cannot support every application to obtain optimal solution when thousands of applications are run simultaneously on resource-bounded servers. Here we propose a heuristic scheme, CPicker, based on genetic programming to improve energy efficiency of servers. To speed up convergence, CPicker initializes a high quality population by first choosing configurations from regions that have high energy variation. Experiments show that CPicker obtains above 17% energy efficiency improvement compared with the greedy approach, and less than 4% efficiency loss compared with the oracle case.     

多核环境下虚拟机VCPU调度研究:问题与挑战

虚拟机VCPU调度策略和机制是影响虚拟机系统性能的关键因素.由于虚拟机系统改变了传统的软件栈结构,简单地将传统操作系统中所采用的调度策略和算法移植到虚拟机监视器层用于虚拟机VCPU的调度,会导致虚拟机系统性能的偏离甚至严重下降,虚拟机系统下层的物理处理器采用多核结构更增加了虚拟机VCPU调度的复杂性.详细介绍并分析了虚...     

一种基于虚拟机技术的嵌入式操作系统移植方案

介绍了虚拟机以及虚拟机目前的广泛应用，提出了一种利用虚拟机技术实现嵌入式操作系统移植的解决方案，并针对这种方案的可行性以及优缺点进行了分析。     

A Mathematical Network Model and a Solution Algorithm for IaaS Cloud Computing

Networks and Spatial Economics - Cloud Computing is a type of Internet-based computing, much used in recent years, that relies on sharing computer processing resources and data to computers and...     

基于形式概念分析的云中虚拟机调度研究

针对云环境中分布式的虚拟机调度问题,首次引入形式概念分析原理,提出基于偏序集的规则算法来发现任务与虚拟机的映射关系。研究工作的重点是首先建立虚拟机任务调度优化模型,并把虚拟机对象转换为形式背景;其次利用偏序关系生成任务与虚拟机的GM偏序图;最后算法先序遍历深度为 n＋1的满二叉树后得出任务与虚拟机的对应关系,并在VC6．0平台中验证了算法的可行性和有效性,为云环境中虚拟机调度提供了一种新的研究途径。     

基于Forth虚拟机的嵌入式多核任务调度研究

由于传统多核任务调度系统对于突发事件的处理,都是基于CPU进行调度的,严重影响了操作系统中任务切换的实时性.于是提出一种基于Forth虚拟机架构的嵌入式多核任务调度系统.为了保证Forth操作系统兼容轮询调度,根据突发事件创建中断任务,并与相应的任务执行程序建立连接.依据中断、终端和后台三种任务间的关联构建循环链表.最后,当突发事件触发中断任务就绪后,Forth系统将调度中断任务去执行突发事件,当中断任务程序运行完毕后,系统继续执行当前任务,执行到原语pause时,当前任务的用户变量将寻找下一任务的TCB首地址,直到所有任务执行完毕.实验结果表明,改进后的Forth虚拟机操作系统响应速度良好,不受任务数量影响,且系统等待时间明显降低,说明所设计的Forth虚拟机操作系统具有良好的多核任务调度性能.     

单机多客户调度的交互式非合作博弈求解

从现代生产应强调客户个体目标的优化需求出发,研究了基于客户评价反馈机制下的单机多客户调度问题.提出并建立了两套客户评价反馈机制,分别以定性和定量的方式反映客户对生产方调度结果的评价,以此确定目标改善工件.然后,在借鉴非合作博弈理论应用思路的基础上,设计Nash均衡(NE)解的调整算法,通过采用个体目标强化因子法和机器资源时间段价格调整法相结合的方法得到NE解.算例仿真表明,该NE解能令客户满意.     

云计算环境中虚拟机内存自适应调节算法研究

Xen虚拟机自身的资源在创建之初已经固定,往往会因某些虚拟机内存不足而使用swap,使得虚拟机工作性能降低,而有的虚拟机内存比较空闲,使得整体虚拟机内存使用效率不高。之前已经有研究对虚拟机使用过程中的内存调度算法进行设计,但是经过推敲发现,之前内存调度算法由于没有考虑swap空间使用情况而导致整体内存调度不够高效。在前人算法研究基础上,提出了一个更加完善合理的内存调度算法,结合swap和内存使用情况一起调节虚拟机内存。算法仍然延续了Carl提出的空闲内存税概念加以设计,首先根据虚拟机内存和swap使用情况确定该次调节周期的调节范围,之后根据各个虚拟机的内存和swap空间使用情况计算虚拟机目标内存。对前后两种算法分别设计实验进行测试,验证了新算法的高效性。     

考虑能耗成本和拖期成本的非同等并行机调度

针对橡胶轮胎硫化车间能源消耗大,浪费严重的现象,提出一类考虑能耗成本与拖期成本的非等同并行机调度问题,建立基于硫化机正常运行、空闲、停机三种运行状态的能源消耗成本与拖期成本的调度模型。设计了基于优先调度规则的启发式算法、基于能耗优化的启发式算法、组合启发式算法用于模型求解,并通过仿真实验分析、比较了各种算法的有效性与适用环境。同时,仿真实验结果也表明本文提出的考虑能耗成本和拖期成本的非同等并行机调度问题具有一定的理论与实践意义。     

单机多客户调度的交互式非合作博弈求解

从现代生产应强调客户个体目标的优化需求出发，研究了基于客户评价反馈机制下的单机多客户调度问题。提出并建立了两套客户评价反馈机制，分别以定性和定量的方式反映客户对生产方调度结果的评价，以此确定目标改善工件。然后，在借鉴非合作博弈理论应用思路的基础上，设计Nash均衡（NE）解的调整算法，通过采用个体目标强化因子法和机器资源时间段价格调整法相结合的方法得到NE解。算例仿真表明，该NE解能今客户满意.     

Scheduling Queries to Improve the Freshness of a Website

The World Wide Web is a new advertising medium that corporations use to increase their exposure to consumers. Very large websites whose content is derived from a source database need to maintain a freshness that reflects changes that are made to the base data. This issue is particularly significant for websites that present fast-changing information such as stock-exchange information and product information. In this article, we formally define and study the freshness of a website that is refreshed by a scheduled set of queries that fetch fresh data from the databases. We propose several online-scheduling algorithms and compare the performance of the algorithms on the freshness metric. We show that maximizing the freshness of a website is a NP-hard problem and that the scheduling algorithm MiEF performs better than the other proposed algorithms. Our conclusion is verified by empirical results.     

提高油井效率的方法和节能措施

抽油机是大庆油田的主要采油设备,但抽油机老化现象比较严重,造成设备利用率低、能耗大.对抽油机能耗大的主要原因进行分析,包括冲次偏大、电机装机功率偏大、泵型偏小等.分析抽油机经济寿命和现有老井抽油机现状可知,更新改造抽油机还有较大的空间和潜力.采用一些方法,能够提高油井的效率,从而能够降低抽油机能耗.     

虚拟机在实践教学中的应用

随着高职院校课程的不断改革深入,越来越重视实践教学。虚拟技术的发展和其自身所具有的特点,被高校广泛的应用在实践教学上。虚拟机的应用不仅充分有效的利用现有设备,而且对硬件设备及系统具有很好的安全性。教学上更加灵活、方便的设计实践项目,从而提高实践教学的质量。     

妙用Word提高办公效率

该文介绍了Word的模板,以及Word表格的设置和格式化。     

巧用流程图提高编程效率

计算机作为现实工作中最重要的一种辅助工具,要想让它发挥作用就必须通过编写相应的程序来告诉它做什么和怎么做,因此软件开发中最关键的一个步骤就是利用流程图等工具将日常事务处理转换成计算机能够理解的处理序列,再寻找合适的编程语言加以实现.巧用活用流程图这种工具能够有效提高程序编写的效率,使程序开发成为一种简单的事情.