Transactional Memory

国家科学基金会分布式系统研究CEISE/CNSABSTRACT建议编号：0410042首席研究员：Herlihy，MauriceInstitution：Brown University建议标题：事务内存这个项目专注于一种称为事务内存的多处理器同步的新方法。这种方法用轻量级事务取代了传统的锁定技术，轻量级事务是一系列可以自动执行的指令。事务性内存依赖于硬件和软件支持的组合。该项目探讨了交易的硬件和软件支持之间的接口。硬件非常适合于访问较小内存区域的短事务，但对于较长的事务或访问更多内存的事务则效率较低。不能直接在硬件中执行的事务必须部分或全部在软件中执行，该项目正在研究一系列可能的权衡。该项目还探索了事务内存模型对高并发数据结构设计的影响。虽然事务内存比传统的锁定技术提供了更好的细粒度并发支持，但它也为新型数据结构设计和算法提供了机会。这个项目解决了现代计算中的一个基本问题。每年，处理器都变得更快、更便宜。然而，最近，散热等基本限制使得时钟速度的进步变得越来越困难。另一种方法称为多处理，它利用多个处理器协同工作。遗憾的是，目前的多处理器同步技术很难使用，并且不适合大规模系统。本项目研究的这种替代同步模型为更有效的多处理器计算提供了一个实质性的障碍。该项目的成果将通过学术出版物和开源软件传播。布雷特·D·弗莱施项目总监，CEISE/CNS2004年5月26日

National Science FoundationDistributed Systems Research CISE/CNSABSTRACTProposal Number: 0410042Principal Investigator: Herlihy, MauriceInstitution: Brown UniversityProposal Title: Transactional MemoryThis project focuses on an new approach to multiprocessor synchronization called transactional memory. This approach replaces conventional locking techniques with light-weight transactions: sequences of instructions that ap-pear to execute atomically. Transactional memory relies on a combination of hardware and software support. The project explores the interface between hardware and software support for transactions. Hardware is well-suited for short transactions that access a small memory region, but is less effective for longer transactions, or transactions that access more memory. Transactions that cannot be executed directly in hardware must be executed partially or en-tirely in software, and the project is investigating a range of possible trade-offs.The project also explores the implications of the transactional memory model for the design of highly-concurrent data structures. While transactional mem-ory provides better support for fine-grained concurrency than conventional ock-ing techniques, it also provides opportunities for new kinds of data structure designs and algorithms.This project addresses a fundamental problem in modern computing. Every year, processors get faster and cheaper. Recently, however, fundamental limita-tions such as heat dissipation have made advances in clock speed increasingly difficult. An alternative approach, called multiprocessing, harnesses multiple processors to work together. Unfortunately, current techniques for multiproc-essor synchronization are difficult to use, and scale poorly to large-scale sys-tems. This alternative synchronization model investigated by this project prom-ises to one substantial barrier to more effective multiprocessor computing. The project's results will be disseminated through scholarly publication andopen-source software.Dr. Brett D. FleischProgram Director, CISE/CNSMay 26, 2004..