ST-CRTS: Collaborative: Delivering on Atomic Actions: Unlocking Concurrency for Ordinary Programmers

背景广泛认识到使用线程和锁进行编程的问题包括争用条件、优先级反转和死锁，这些问题都是出了名的难以避免和诊断。我们需要更好的抽象，以供普通程序员使用来利用并发性。解决锁问题的一个有希望的方向是各种形式的原子动作(AA)。原子动作是保证看起来会发生的计算动作的集合：要么完全发生，要么根本不发生，并且相对于其他AA以一定的顺序进行。类似Atom的概念在数据库应用程序中获得了巨大成功。智能优点-针对AA的精确编程模型，重点放在封闭和开放嵌套上。-在现有硬件上实现替代AA的开销。-增加并行度带来的AA的性能优势，尽管它们有开销。-硬件-AA的辅助：硬件接口(API)和虚拟化，以掩盖硬件限制。-AA与I/O、网络等非事务性活动的对比。-AA与垃圾收集(GC)、异常和陷阱等运行时服务的对比。-用于分析和调整AA、AS性能的工具以及它们的改进：瓶颈。布罗德影响交付AAS将通过提高新商用硬件应用程序的健壮性和性能，带来显著的经济和安全好处。AAS将有可能提高软件的并发性，从而提高软件的性能，同时还可以提高可靠性并简化调整和维护。普通程序员将更容易地在桌面上利用线程级并行，编写他们不会编写的程序，并在此之前开始工作。该项目将通过开发他们的新产品而使硬件行业受益，通过增加并发软件的健壮性而使软件行业受益，同时也有助于经济和国家安全。所有项目成果和工具都将向公众开放，该项目将对学员进行重要的高需求技能培训，从而为技术队伍做出贡献。

BackgroundWidely recognized problems of programming with threads and locks include race conditions,priority inversion, and deadlock, problems notoriously difficult both to avoid and to diagnose.We need better abstractions for ordinary programmers to use to exploit concurrency. A promisingdirection that solves the problems with locks is the various forms of atomic action (AA).An AA is a collection of computational actions that are guaranteed to appear to occur: eitherentirely or not at all, and in a definite order with respect to other AAs. Atom-like notionshave enjoyed great success in database applications.Intellectual Merit-A precise programming model for AAs, with a focus on closed and open nesting.- Overheads of alternative AA implementations on existing hardware.- Performance benefits of AAs resulting from increased parallelism, despite their overheads.- Hardware-assist for AAs: hardware interfaces (APIs) and virtualization to mask hardware limits.- AAs vis-a-vis non-transactional activities such as I/O, networking, etc.- AAs vis-a-vis run-time services such as garbage collection (GC), exceptions, and traps.- Tools for profiling and tuning performance of AAs, and their refinement re: bottlenecks.Broader ImpactDelivering on AAs will lead to significant economic and security benefitsthrough improved robustness and performance of applications for new commodity hardware. AAswill make it possible to increase concurrency, and thus performance, of software while also increasingreliability and simplifying tuning and maintenance. Ordinary programmers will more readily exploitthread-level parallelism on the desktop, writing programs they could not write, and get to work, before.The project will benefit the hardware industry by exploiting their new offerings, and the softwareindustry by increasing the robustness of concurrent software, while also contributing to economic andnational security. All project results and tools will be available to the public, and the project will traingraduates in important high-demand skills, and thus contribute to the technical work-force.