CSR: Small: Multi-Version Concurrency Control (MVCC) for Main Memory and its Implications for Deterministic Concurrency

CSR：小：主内存的多版本并发控制 (MVCC) 及其对确定性并发的影响

• 批准号: 1320235
• 负责人: Jakob Eriksson
• 金额: $ 45.37万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-10-01 至 2017-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1320235&HistoricalAwards=false
• 关键词: CSR; Small; Multi; Version; Concurrency

The objective of this project is to investigate version consistency, a new concurrent programming consistency model, as a means of enhancing the performance and scalability of concurrent systems. Under version consistency, which can be seen as a relaxation of release consistency, processes are guaranteed to see the same memory contents (only) if they are accessing the same version of the memory. Such versions are created, retrieved and/or merged through calls analogous with version control systems for source code.An important class of applications that benefits substantially from version consistency is deterministic concurrency runtimes, where the goal is to ensure that a program produces the same output given the same input, independent of any non-deterministic timing effects. In prior work, the PI achieved up to 50% performance gain for the deterministic runtime DThreads, using version consistency. In this project, one of the goals is to achieve ``pthreads parity" for a deterministic runtime, where enforcing determinism incurs only negligible performance impact. When and if this is achieved, ``determinism by default'' becomes a feasible option for mainstream computer systems.As computer processors continue to evolve from a centralized single ``core'' architecture to highly distributed and parallel ``multi-core systems'', writing correct programs that make efficient use of this extremely powerful hardware is becoming increasingly difficult. This results in a number of detrimental effects ranging from poor resource utilization, to seriously flawed programs where loss of data, or even loss of life may result. This project investigates (a) a means of reducing the complexity of programming highly parallel systems to combat these problems, and (b) a means of guaranteeing that even an incorrect parallel program produces the same result every time. This latter part will help programmers write correct programs, and to fix software flaws that may otherwise be intermittent and difficult to identify.

该项目的目标是研究版本一致性（一种新的并发编程一致性模型），作为增强并发系统性能和可扩展性的一种手段。在版本一致性下，可以看作是释放一致性的放宽，只有当进程访问相同版本的内存时，才能保证看到相同的内存内容。这些版本是通过类似于源代码版本控制系统的调用来创建、检索和/或合并的。从版本一致性中受益匪浅的一类重要应用程序是确定性并发运行时，其目标是确保程序产生相同的输出给定相同的输入，独立于任何非确定性时序效应。在之前的工作中，PI 使用版本一致性，为确定性运行时 DThread 实现了高达 50% 的性能提升。在这个项目中，目标之一是实现确定性运行时的“pthreads 奇偶校验”，其中强制执行确定性只会对性能产生微不足道的影响。当实现这一点时，“默认确定性”将成为主流的可行选择随着计算机处理器不断从集中式单“核”架构发展到高度分布式和并行的“多核系统”，编写正确的程序来有效利用这种极其强大的硬件变得越来越困难。这个结果该项目研究了（a）一种降低高度并行系统编程复杂性的方法来解决这些问题。 ，以及（b）一种保证即使不正确的并行程序每次都会产生相同结果的方法，后一部分将帮助程序员编写正确的程序，并修复可能是间歇性的且难以识别的软件缺陷。