一种面向有环兴趣路径的过程内剖析方法

An Approach of Profiling Selected Paths with Loops

路径剖析技术用于获取和分析程序中各条路径的执行次数.路径剖析采用在待剖析程序中插装探针的方式以跟踪执行,并使用对路径进行编码的方式以高效地获取剖析结果.选择性剖析是针对用户感兴趣的一部分路径,在非选择性剖析技术的基础上进行优化,以尽可能低的耗费来完成剖析.现有的选择性剖析技术采用的优化措施局限于减少探针数目和压缩路径编码空间,而且其允许的用户兴趣路径局限于无环路径.文中提出了一种新的选择性剖析方法 PSP(Profiling Selected Paths),可以精确的剖析带有循环的兴趣路径,并使用了在执行过程中对非兴趣路径进行检测和提前终止的技术来降低耗费.理论分析和实验评估表明PSP方法能够精确地剖析兴趣路径,并使用兴趣路径来提升剖析效率.

Path profiling records the frequency of each path in an executed program. To accom- plish profiling, probes are instrumented in the program and executed as the program runs. So the number of probes has a significant impact on the efficiency of a profiling technique. By profiling only the interesting paths, existing techniques try to improve the profiling efficiency by reducing probes and optimizing path encodings for efficient storage. However, they lack accuracy, waste time on running uninteresting paths, and mainly deal with acyclic paths. In this paper, a novel technique called PSP （Profiling Selected Paths） is introduced to profile selected paths, which enables custom selection for both acyclic and cyclic paths, and increases the execution efficiency by early termination on uninteresting paths. Theoretical analysis and experimental evaluation indicate that PSP performs effectively in optimization of selective profiling.