Hyper-V and Multiprocessor VMs

Hyper-V uses a hypervisor-based architecture and leverages the driver model of Windows for broad hardware support. The hypervisor partitions a server into containers of CPU and memory. As a micro-kernel, it provides mechanisms for inter-partition communication upon which our new high-performance synthetic I/O architecture is built. The root partition owns physical I/O devices and provides […]

Hyper-V uses a hypervisor-based architecture and leverages the driver model of Windows for broad hardware support. The hypervisor partitions a server into containers of CPU and memory. As a micro-kernel, it provides mechanisms for inter-partition communication upon which our new high-performance synthetic I/O architecture is built. The root partition owns physical I/O devices and provides services including I/O implemented by the virtualization stack to the child partitions.

The virtualization stack implements emulated I/O devices such as an IDE controller and a DEC 21140A network adapter. However, it is expensive to virtualize such devices. Sending a single I/O might require multiple trips between the virtualization stack and child partition. Instead, Hyper-V exposes synthetic I/O devices that are specially designed for VM environments. These devices are attached to VMBus, which is a plug-and-play capable bus that uses shared memory for efficient inter-partition communication. The Windows guests detect the devices on VMBus and loads the appropriate drivers.

Synthetic I/O in Hyper-V uses a client-server architecture with Virtualization Service Providers (VSPs) in the root and Virtualization Service Clients (VSCs) in the child. This architecture significantly reduces the cost of sending an I/O. Virtual Server customers should observe a major reduction in CPU usage in I/O-intensive loads when they migrate their VMs to Hyper-V.

In addition, we developed operating system enlightenments for Windows Server 2008, which make the NT kernel and memory manager smarter in VM environments, again to reduce the cost of virtualization.

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Microsoft, Windows Server 2008, WS2008, Win2K8, Windows Server, Hyper-V, Multiprocessor, Virtyalization