USENIX HotPar 2013, San Jose, CA. But How Do We Really Debug Transactional Memory Programs?

With recent announcements of hardware transactional mem-ory (HTM) systems from IBM and Intel, HTM will soon be available for widescale adoption. Such platforms, com-bined with tested and stable software transactional memory systems, are likely to make real transactional memory (TM) systems available for the first time, which promises to be a more attractive alternative than lock-based parallel program-ming in terms of programmability and performance. With these first-ever real systems come several open ques-tions. Perhaps one of the most obvious is, “how does one debug a TM program that uses real hardware? ” While prior research in this area exists, there are, to the best of our knowledge, no commercially-available TM debuggers and only a handful of research projects exploring such possibil-ities, many of which use simulated HTMs that may utilize unrealistic hardware. In this paper, we motivate the need for more than traditional and ad hoc debugging support. We then propose a novel record-and-replay system, based on exist-ing research prototypes and demonstrate its usefulness by reviewing several use cases in TM programming, restricting use to real features in IBM and Intel’s HTMs. 1