Efficient Debugging of Parallel Programs

这个项目介绍了设计和实现并行程序调试系统的技术和算法。回流分析的使用提供了有关程序执行中事件之间的因果关系的信息，而不必重新执行程序以进行调试。回流分析直接将程序员集中在问题的原因上。主要解决了两个问题：(1)通过开发一种方法来显著减少程序执行过程中的开销，使回流分析变得实用；(2)将回流分析的语义扩展到并行程序。增量跟踪使用被调试程序的语义分析，使回退分析变得实用，只需在执行过程中生成少量跟踪。回流分析被扩展到应用于并行程序，处理同步活动、进程之间的依赖关系和共享内存访问。还描述了一种在合作进程的交互中检测竞争条件的方法。高效调试并行和顺序程序所需的技术和算法被结合到建立在商用多处理器上的原型系统中。

This project addresses techniques algorithms for design and implementation of a debugging system for parallel programs. The use of flowback analysis provides information on causal relationships between events in a program's execution, without having to re-execute the program for debugging. Flowback analysis directly focuses the programmer on the cause of a problem. Two major issues are addressed: (1) making flowback analysis practical by developing a method that significantly reduces the overhead induced during program execution, and (2) extending the semantics of flowback analysis to parallel programs. Incremental tracing, using semantic analyses of the debugged program, makes the folwback analysis practical with only a small amount of trace generated during execution. Flowback analysis is extended to apply to parallel programs, handling synchronization activities, dependencies between processes, and shared memory access. A method to detect race conditions in the interactions of the co-operating processes is also described. The techniques and algorithms necessary to efficiently debugging both parallel and sequential programs are incorporated in a prototype system built on a commercially available multiprocessor.