ActiveOS: virtualizing intelligent memory

Current trends in DRAM memory chip fabrication have led many researchers to propose "intelligent memory" architectures that integrate microprocessors or logic with memory. Such architectures offer a potential solution, to the growing communication bottleneck between conventional microprocessors and memory. Previous studies, however, have focused upon single-chip systems and have largely neglected off-chip communication in larger systems. We introduce ActiveOS, an operating system which demonstrates multi-process execution on Active Pages, a page-based intelligent memory architecture. We present results from multiprogrammed workloads running on a prototype operating system implemented on top of the SimpleScalar processor simulator. Our results indicate that paging and inter-chip communication can be scheduled to achieve high performance for applications that use Active Pages with minimal adverse effects to applications that only use conventional pages. Overall, ActiveOS allows Active Pages to accelerate individual applications by up to 1000 percent and to accelerate total workloads from 20 to 60 percent as long as physical memory can contain the working set of each individual application.