CSR--PDOS: Fulfilling the Promise of Transactions in Multithreaded Systems

所有主要的微处理器供应商现在都致力于多线程和多核处理器，这使得应用程序程序员可以看到线程级并行。越来越多的共识认为，传统的基于锁的编程技术不足以对这些机器进行编程，而事务是最有前途的替代方案。该项目的中心目标是绘制一条到未来交易系统的可行过渡路径。这个目标包括以下方面的工作：(1)语义扩展，包括异常、条件、嵌套、不可逆操作和互操作性；(2)表征和最小化软件事务的成本；(3)硬件辅助的开发；以及(4)与事务互操作的快速自组织非阻塞数据结构。这些方面的工作横跨编译器、运行时系统、操作系统内核和高级硬件体系结构，重点放在运行时级别。预期的影响和结果包括事务性内存的高性能、开源、库级实现；标准语言库的高性能非阻塞数据结构(示例已经被Java的标准版本采用)；对事务语义以及事务、锁和非阻塞数据结构之间的关系的更深入的理解；新的硬件实现技术；以及适当的编译器支持。更广泛地说，事务性存储的全面路线图有望在未来十年内扩展摩尔定律和IT革命，为科学、商业、政府和生活质量带来广泛的好处。

All major microprocessor vendors are now committed to multi-threaded andmulti-core processors, which make thread-level parallelism visible tothe application programmer. A growing consensus holds that traditionallock-based programming techniques are inadequate to program thesemachines, and that transactions are the most promising alternative. Thecentral goal of the project is to chart a viable transition path tofuture transactional systems. This goal encompasses work on (1)semantic extensions, including exceptions, conditions, nesting,irreversible operations, and interoperability; (2) characterization andminimization of the costs of software transactions; (3) development ofhardware assists; and (4) fast ad-hoc nonblocking data structures thatinteroperate with transactions. Work on these fronts spans thecompiler, run-time system, OS kernel, and high-level hardwarearchitecture, with an emphasis on the run-time level. Expected impactsand outcomes include a high-performance, open-source, library-levelimplementation of transactional memory; high-performance nonblockingdata structures for standard language libraries (examples have alreadybeen adopted for the standard release of Java); a deeper understandingof transactional semantics, and of the relationships among transactions,locks, and nonblocking data structures; new hardware implementationtechniques; and appropriate compiler support. More broadly, acomprehensive roadmap for transactional memory holds the promise ofextending Moore's Law and the IT revolution through the coming decade,with wide-ranging benefits for science, commerce, government, andquality of life.