Collaborative Research: Progress-Based Resource Management Using Control

协作研究：使用控制进行基于进度的资源管理

• 批准号: 9988435
• 负责人: Molly Shor
• 金额: $ 15万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9988435&HistoricalAwards=false
• 关键词: Collaborative; Research; Progress; Based; Resource

A consequence of the digital revolution is that general purpose computers are being applied to an ever increasing range of applications. However, lack of suitable operating system support remains a key obstacle in applying COTS (commodity-off-the-shelf) computers to many of these application domains, particularly those whose correctness is time- or rate-sensitive. One important feature that is missing in existing operating systems is the ability to assign resources to applications based on application need. This feature is needed to prevent one application from affecting the correctness of another, such as occurs in priority inversion, and to achieve near-optimal resource allocation in the face of oversubscription of resources and changes in application need over time.Steere and Walpole introduced a novel approach to resource management, progress-based resourcemanagement, that allocates resources to applications based on perceived need. The scheduler monitors anapplication's rate of progress, compares these measurements with the application's desired rate, andincreases or decreases the application's allocation to drive its actual rate to its desired value. Initial experi-ence with prototypes is promising. A CPU allocator uses a feedback controller (low-pass filter followed bya PID controller) to regulate buffer fill levels in a multimedia pipeline by dynamically changing reservation style allocations of the pipeline threads. They have also used the same approach to allocate network bandwidth in an end-host packet scheduler.Their experience with these prototypes indicates a strong need for more formal modeling and analysis. The prototypes are difficult to tune correctly; since correct performance depends both on the controller's parameter settings and the behavior of the application, which can change. In addition, the presence of adaptive applications (such as adaptive QoS) can lead an otherwise stable system to oscillate or diverge. Standard computer science formal methods do not help one to understand a system's adaptive behavior, since they focus on interface syntax and semantics. What is needed is analytical techniques for understanding the behavior of a dynamic system over time, such as those used in control systems.At the same time, applying control-style modeling and analysis to software systems is itself a research challenge. Software systems are discrete by nature, and one must consider quantization error not only in sampling and representation of data values but also in the underlying signal itself. In addition, software applications such as pipelines contend for access to managed resources such as CPU and memory but also to unmanaged resources such as synchronization variables (locks and semaphores). These synchronization issues make it difficult to predict the effect of a change in allocation for one resource, and hence to design a controller for that resource.

数字革命的一个结果是，通用计算机正被应用于越来越多的应用领域。然而，缺乏合适的操作系统的支持仍然是一个关键的障碍，在应用COTS（商品现货）计算机的许多这些应用领域，特别是那些正确性是时间或速率敏感。现有操作系统中缺少的一个重要功能是基于应用程序需要将资源分配给应用程序的能力。此功能是必要的，以防止一个应用程序的正确性受到影响的另一个，如发生在优先级反转，并实现接近最佳的资源分配，面对超额认购的资源和变化的应用程序需要随着时间的推移Steere和Walpole介绍了一种新的方法，资源管理，基于进度的资源管理，分配资源的应用程序的基础上感知的需要。调度程序监视应用程序的进度，将这些测量结果与应用程序的期望速率进行比较，并增加或减少应用程序的分配，以将其实际速率驱动到期望值。原型的初步经验是有希望的。CPU分配器使用反馈控制器（低通滤波器，后接PID控制器），通过动态改变流水线线程的预留样式分配来调节多媒体流水线中的缓冲器填充水平。他们也用同样的方法在终端主机包调度器中分配网络带宽，他们在这些原型上的经验表明，非常需要更正式的建模和分析。 原型很难正确地调优;因为正确的性能取决于控制器的参数设置和应用程序的行为，而这些行为可能会发生变化。此外，自适应应用程序（如自适应QoS）的存在可能会导致一个原本稳定的系统振荡或发散。标准的计算机科学形式化方法并不能帮助人们理解系统的自适应行为，因为它们关注的是接口的语法和语义。需要的是分析技术来理解动态系统随时间的行为，例如控制系统中使用的分析技术。同时，将控制风格的建模和分析应用于软件系统本身就是一个研究挑战。软件系统本质上是离散的，不仅在数据值的采样和表示中，而且在底层信号本身中，都必须考虑量化误差。此外，诸如流水线之类的软件应用程序不仅争用对诸如CPU和存储器之类的托管资源的访问，而且争用对诸如同步变量（锁和信号量）之类的非托管资源的访问。这些同步问题使得难以预测一个资源的分配变化的影响，因此难以为该资源设计控制器。