优化记录法在PVM中的改进和应用

THE IMPROVEMENT AND APPLICATION OF OPTIMAL TRACING IN PVM

并行程序的不确定性使其调试时不能象串行程序调试那样通过反复执行程序来查找错误，因此，记录并重演是并行调试的关键技术，而这一技术的最大开销就是事件的记录．本文结合PVM（Parallelvirtualmachine）的特点，改进了Netzer等人提出的优化记录法，使事件记录在出现非传递的消息竞争时也是最优的，并保证同一进程发送消息时，不会象原算法一样可能进行记录，同时，还在PVM并行调试环境中实现了该方法．

Parallel programs can not be debugged as sequential ones repeatly because of their nondetermination, so tracing and replay become the key technique of parallel debug ging, and the most overhead of this technique is tracing the events. This paper improves the optimal tracing method provided by Rober Netzer etc. by combining the characteristics of PVM (parallel virtual machine), makes the events tracing optimal even when non-transitive message race appears. The improved method has been implemented in PVM-based parallel clebugger.