SELF: Improving the Memory-Sharing Opportunity using Virtual-Machine Self-Hints in Virtualized Systems

Currently, most data centers consolidate servers using virtualization technology to reduce power consumption and the server's environmental "footprint." In these virtualized systems, page-sharing has been widely studied and adopted to increase the degree of consolidation, thereby increasing the chance of power saving. Traditional page-sharing schemes miss the sharing opportunities of short-lived pages, and performance degradation is caused by an exhaustive sequential scanning of the memory content. In this paper, we introduce SELF, an enhanced scheme for page-sharing in virtualized systems. We mitigated the semantic gap between the guest and host by applying a self-hint module to each virtual machine (VM), and, by exploiting the hints of the VMs, we can preferentially compare pages with high sharing probability. Through quantitative experiments, we verified that SELF could obtain new sharing opportunities by specifying directories that have high sharing probability, with low overhead.