CSR: Small: A Framework for Advanced Concurrency Debugging

CSR：小型：高级并发调试框架

• 批准号: 1116237
• 负责人: Josep Torrellas
• 金额: $ 43万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1116237&HistoricalAwards=false
• 关键词: CSR; Small; Framework; Advanced; Concurrency

This work addresses the capture of concurrency bugs that can occur in parallel software, focusing on four types of concurrency bugs that are frequent, have received little attention, and are hard to fix.The first type is atomicity violations -- bugs that occurs when the programmer fails to enclose in the same critical section all of the memory accesses that should occur atomically. As a result, during execution, such accesses get interleaved with accesses from another thread that make the program state inconsistent.The second type is over-synchronization -- a defect that implies that there are redundant synchronization operations or that the synchronization operations are performed at a grain that is too coarse. As a result, the program's performance is poor.The third type is ordering violations ? these occur when there is a correct order between memory accesses from different threads and, in an execution, such order is flipped, usually due to not using the correct form of synchronization.The final type is asymmetric data races ? bugs that occur when a thread accesses shared variables inside a critical section with appropriate synchronization. However, a second thread concurrently accesses the same shared variables without synchronization, and makes the state inconsistent.The approach taken by this project involves characterizing these bugs and proposing techniques to detect and fix them. A deliverable of this work is a unified framework for bug detection.The realization of parallel programming is a Grand Research Challenge and is crucial to our computer industry's ability to continue to make progress. The University of Illinois is a leader in parallel computing and the outcomes of this proposal will be used to enhance courses on parallel computing. In addition, this project will involve close collaboration with Intel and provide students with the opportunity to engage in internships at Intel.

这项工作解决了在并行软件中可能发生的并发错误的捕获问题，重点关注四种类型的并发错误，这些错误是频繁的、很少受到关注的、很难修复的。第一种类型是原子性违规--程序员未能将本应自动发生的所有内存访问包含在同一关键部分中时发生的错误。因此，在执行期间，这样的访问会与来自另一个线程的访问交错，从而导致程序状态不一致。第二种类型是过度同步--这一缺陷意味着存在冗余的同步操作，或者同步操作是以太粗的粒度执行的。因此，程序的性能很差。第三种类型是排序违规吗？当来自不同线程的内存访问之间存在正确的顺序，并且在执行中，这种顺序被颠倒时，通常是由于没有使用正确的同步形式，就会发生这种情况。最后一种类型是不对称数据竞争？线程通过适当的同步访问临界区内的共享变量时发生的错误。然而，第二个线程在不同步的情况下并发访问相同的共享变量，导致状态不一致。该项目采取的方法包括表征这些错误并提出检测和修复它们的技术。这项工作的一个成果是一个用于错误检测的统一框架。实现并行编程是一项巨大的研究挑战，对我们计算机行业继续取得进展的能力至关重要。伊利诺伊大学是并行计算领域的领先者，这项提案的成果将用于加强并行计算课程。此外，该项目将涉及与英特尔的密切合作，并为学生提供在英特尔实习的机会。