Bungale HDTrans: An Open Source, Low-Level Dynamic Instrumentation System

Dynamic translation is a general purpose tool used for instrument-ing programs at run time. Performance of translated execution re-lies on balancing the cost of translation against the benefits of any optimizations achieved, and many current translators perform sub-stantial rewriting during translation in an attempt to reduce execu-tion time. Our results show that these optimizations offer no sig-nificant benefit even when the translated program has a small, hot working set. When used in a broader range of applications, such as ubiquitous policy enforcement or penetration detection, transla-tor performance cannot rely on the presence of a hot working set to amortize the cost of translation. A simpler, more maintainable, adaptable, and smaller translator appears preferable to more com-plicated designs in most cases. HDTrans is a light-weight dynamic instrumentation system for the IA-32 architecture that uses some simple and effective trans-lation techniques in combination with established trace lineariza-tion and code caching optimizations. We present an evaluation of translation overhead under both benchmark and less idealized con-ditions, showing that conventional benchmarks do not provide a good prediction of translation overhead when used pervasively. A further contribution of this paper is an analysis of the effec-tiveness of post-link static pre-translation techniques for overhead reduction. Our results indicate that static pre-translation is effective only when expensive instrumentation or optimization is performed