Exploring IO in a Virtual Machine Environment
Elango Pradheep, Krishnakumaran Saisuresh
Abstract: In virtualized environments, an operating system may not have complete knowledge about its resources as it sees only virtualized forms of physical resources. In this paper, we study how the lack of information about a disk's activity can affect performance of a virtual machine. Specifically, we address how information about disk idleness can be passed to virtual machines so that such periods can be effectively utilized to maximize disk bandwidth. The main focus of this paper is the discussion of various mechanisms that could be applicable in a virtualized environment in order to effectively expose such information and exercise control. In order to effectively exercise control, we discuss designs to infer the number of dirty pages in each domain from the VMM. Further, we discuss some on-going implementation of a few of these designs.
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