Compiler Assisted Speculation for Multithreaded Programming

Multithreaded programming, which well fits the structure of modern shared memory systems, is becoming one of the most popular parallel programming models. Two important supporting components of multithreaded programming, concurrent data structures and transactional memory, can benefit from speculation. However, traditional speculation mechanisms, which do not exploit high level knowledge about the program, are inefficient in concurrent data structures and transactional memory systems. In this proposal, we bridge the gap between the high-level program knowledge and the speculation in multithreaded programming with the compiler’s assistance. We propose a language extension to incorporate fast speculation into concurrent data structure design, and show how the language extension helps the speculation in newly emerged HTM processors. Besides, in order to improve the speculation in transaction memory systems under the circumstance with data high contention, two compiler optimization techniques are also proposed for STM and HTM, respectively.