实时系统调度：理论与实践

需积分: 9 64 浏览量更新于2024-07-23 收藏 1.88MB PDF 举报

"Scheduling in Real-Time Systems" 是一本专注于实时系统调度的专业书籍，由Francis Cottet, Joëlle Delacroix, Claude Kaiser和Zoubir Mammeri等专家合著，旨在为该领域的学者提供深入理解与指导。实时系统调度是计算机科学中的一个重要领域，特别是对于那些对系统性能和响应时间有严格要求的应用，例如航空电子、自动化控制、医疗设备和嵌入式系统等。在这些应用中，任务必须在预定义的时间限制内完成，否则可能导致严重后果，甚至系统崩溃。本书可能涵盖了以下关键知识点： 1. **实时性概念**：解释实时系统的特性，如截止期限（deadlines）、紧迫度（urgency）和确定性（determinism），这些都是调度策略设计的基础。 2. **调度策略分类**：包括抢占式（preemptive）和非抢占式（non-preemptive）调度，以及基于优先级（priority-based）、固定周期（fixed-priority）、动态调度（dynamic scheduling）等不同策略的比较和适用场景。 3. **任务模型**：讨论不同类型的实时任务模型，如独立任务（independent tasks）、相关任务（dependent tasks）、间歇任务（sporadic tasks）和持续任务（continuous tasks），以及它们对调度的影响。 4. **调度算法**：详细讲解各种实时调度算法，如Earliest Deadline First (EDF)、Least Laxity First (LLF)、Rate Monotonic (RM) 和Priority Ceiling Protocol (PCP)等，分析其优缺点和适用环境。 5. **资源分配**：阐述如何在有限的硬件资源（如处理器时间、内存等）下进行有效的任务分配，以满足实时约束。 6. **性能评估**：介绍评估调度性能的指标，如任务完成率（task completion rate）、错过截止期限的次数（missed deadlines）和平均延迟（average latency）等。 7. **实时操作系统**：讨论实时操作系统的特性，如中断处理、内存管理、中断延迟和上下文切换开销，以及它们如何影响调度性能。 8. **多核和分布式实时系统调度**：随着技术的发展，书中可能会涵盖多处理器和分布式系统的调度挑战及解决方案。 9. **实时调度的挑战与未来趋势**：分析实时调度面临的挑战，如能量效率、可扩展性和适应性，并探讨未来的研究方向。 10. **实例应用与案例研究**：通过实际案例分析，展示理论知识在实际系统设计和优化中的应用。 "Scheduling in Real-Time Systems" 提供了实时系统调度的全面视图，不仅介绍了基础理论，还涵盖了最新的研究成果和实践应用，是学习和研究实时系统调度的宝贵资源。

INTRODUCTION xv

symmetric multiprocessor systems sharing a common memory. Chapter 6 discusses

how to evaluate the message transmission delays in several kinds of widely used

real-time industrial networks and how to schedule messages e xchanged between tasks

of a distributed application supported by a local area network. Chapter 7 considers

the case of packet-switching networks and the scheduling of packets in order to

guarantee the packet transfer delay a nd to limit the delay jitter. Chapter 8 approaches

different software environments for real-time applications, such as operating systems,

asynchronous and synchronous languages, and distributed platforms. Chapter 9 deals

with three relevant case studies: the ﬁrst example describes the real-time acquisition and

analysis of the signals providing from an aluminium rolling mill in the Pechiney plant,

which manufactures aluminium reels for the packaging market; the second example

presents the control system of the robot that the Pathﬁnder space vehicle landed on

Mars, and it analyses the failure that was caused by a wrong sharing of the bus of the

control computer. The last example describes the tasks and messages that are present

in a distributed architecture supporting a car control system, and it analyses some

temporal behaviours of these tasks.

Exercises appear at the end of some of the chapters. Other exercises can be deduced

from the case studies (rolling mill, robot control and car control system) presented in

Chapter 9. A glossary, given at the end of the book, provides deﬁnitions for many of

the technical terms used in real-time scheduling.

Basic Concepts

1.1 Real-Time Applications

1.1.1 Real-time applications issues

In real-time applications, the timing requirements are the main constraints and their

mastering is the predominant factor for assessing the quality of service. Timing con-

straints span many application areas, such as industrial plant automation, embedded

systems, vehicle control, nuclear plant monitoring, scientiﬁc experiment guidance,

robotics, multimedia audio and video stream conditioning, surgical operation moni-

toring, and stock exchange orders follow-up.

Applications trigger periodic or random events and require that the associated com-

puter system reacts before a given delay or a ﬁxed time. The timing latitude to react

is limited since transient data must be caught, actions have a constraint on both start

and ﬁnish times, and responses or commands must be sent on time.

The time scale may vary largely, its magnitude being a microsecond in a radar, a

second in a human–machine interface, a minute in an assembly line, or an hour in a

chemical reaction.

The source of timing constraints leads to classifying them as hard or soft. A real-time

system has hard timing constraints when a timing fault (missing a deadline, delivering

a message too late, sampling data irregularly, too large a scatter in data supposed to

be collected simultaneously) may cause some human, economic or ecological disaster.

A real-time system has soft timing constraints when timing faults can be dealt with to

a certain extent.

A real-time computer system is a computer system whose behaviour is ﬁxed by

the dynamics of the application. Therefore, a real-time application consists of two

connected parts: the controlling real-time computer system and the controlled process

(Figure 1.1).

Time mastery is a serious challenge for real-time computer systems, and it is often

misunderstood. The correctness of system reactions depends not only on the logical

results of the computations, but also on the time at which the results are produced.

Correct data which are available too late are useless; this is a timing fault (Burns and

Wellings, 1997; Lelann, 1990; Stankovic, 1988).

A controlling real-time computer system may be built as:

• a cyclic generator, which periodically samples the state of the controlled process,

computes the measured data and sends orders to the actuators (this is also called

synchronous control);

剩余283页未读，继续阅读

zyf_1990

粉丝: 1
资源: 15

实时系统调度：理论与实践

Real-Time Systems Architecture Scheduling and Application 2016

Handbook of Real-Time and Embedded Systems

Hard Real-Time Computing Systems 3rd edition

real time linux

进程调度模拟实验源代码

optimal economic scheduling onsharing energy-storage station.zip

找十条中英文关于企业会议室预约与管理系统的参考文献以及段落

在嵌入式linux中创建4个进程，两个实时进程，两个非实时进程

最新资源