Shared virtual memory: Progress and challenges

Shared virtual memory, a technique for supporting a shared address space in software on parallel systems, has undergone a decade of research, with sig nificant maturing of protocols and communication layers having now been ach ieved. We provide a survey of the key developments in this research, placin g the multitrack flow of ideas and results obtained so far in a comprehensi ve new framework. Four major research tracks are covered: relaxed consisten cy models; protocol laziness; architectural support; and application driven research. Several related avenues are also discussed, such as fine-grained software coherence, software protocols across multiprocessor nodes, and pe rformance scalability. We summarize comparative performance results from th e literature, discuss their limitations and identify lessons learned so far , key outstanding questions, and important directions for future research i n this area.