Speculative Optimizations for Parallel Programs on Multicores

The advent of multicores presents a promising opportunity for exploiting fine grained parallelism present in programs. Programs parallelized in the above fashion, typically involve threads that communicate via shared memory, and synchronize with each other frequently to ensure that shared memory dependences between different threads are correctly enforced. Such frequent synchronization operations, although required, can greatly affect program performance. In addition to forcing threads to wait for other threads and do no useful work, they also force the compiler to make conservative assumptions in generating code. We analyzed a set of parallel programs with fine grained barrier synchronizations, and observed that the synchronizations used by these programs enforce interprocessor dependences which arise relatively infrequently. Motivated by this observation, our approach consists of creating two versions of the section of code between consecutive synchronization operations; one vers...

• Type: Conference
• Year: 2009
• Where: LCPC
• Authors: Vijay Nagarajan, Rajiv Gupta
• Keywords: Barrier Synchronizations, Interprocessor Dependences, LCPC 2009, Synchronization Operation, System Software