EHCS(EHS), TM: Real-Time Synchronization on Multicore Platforms

多核平台的出现重新引起了人们对多处理器实时系统的兴趣，最近有相当多的工作针对调度问题。不幸的是，相比之下，同样重要的同步主题在某种程度上被忽视了。事实上，在这个主题上最有影响力的工作是在几十年前完成的，当时多处理器实时应用程序被认为主要是“学术”兴趣。该项目的目标是根据正在进行的多核革命重新审视实时同步问题，目的是设计可以实际应用的机制。这个项目的基本原则是“简单取胜”。具体来说，实时同步机制虽然普遍适用，但在设计时应该考虑到常见场景，使用可以合理分析的简单技术。这就引出了一个问题：常见情况是什么？为了确定这一点，在这个项目中收集了关于各种实时应用程序的同步行为的跟踪数据。然后，这些数据被用于生成实时同步基准，这将指导开发工作。这些努力考虑了：实时多处理器锁定协议；支持读为主同步的技术；在实时应用程序中使用事务性内存和非阻塞同步；同步技术可以应用于实时和非实时组件共存的环境中。更广泛的影响包括与at&t、霍尼韦尔（Honeywell）、IBM、英特尔（Intel）和Sun等公司的业界同事进行联合研究，以及开发可供其他机构用于研究和教学目的的公开可用的开源软件。

The advent of multicore platforms has led to renewed interest in multiprocessor real-time systems, with considerable recent work directed at scheduling issues. Unfortunately, the equally-important topic of synchronization, in comparison, has been somewhat neglected. Indeed, the most influential work on this topic was done decades ago, at a time when multiprocessor real-time applications were deemed to be mostly of "academic" interest only. The objective of this project is to re-visit the issue of real-time synchronization in light of the ongoing multicore revolution, with the goal of devising mechanisms that can be practically applied. The fundamental thesis of this project is "simplicity wins." Specifically, real-time synchronization mechanisms, though generally applicable, should be designed with common-case scenarios in mind, using simple techniques that can be reasonably analyzed. This begs the question: What is the common case? To determine this, trace data is collected in this project concerning the synchronization behavior of a wide range of real-time applications. This data is then being used to produce real-time synchronization benchmarks, which will guide development efforts. These efforts consider: real-time multiprocessor locking protocols; techniques for supporting read-mostly synchronization; the use of transactional memory and non-blocking synchronization in real-time applications; and synchronization techniques that can be applied in settings where both real-time and non-real-time components co-exist. Broader impacts include joint research with industry colleagues at AT&T, Honeywell, IBM, Intel, and Sun, and the development of publicly-available open-source software that can be used by other institutions for research and teaching purposes.