News Column

Patent Issued for Virtual Machine Monitor and Multiprocessor System

September 9, 2014

By a News Reporter-Staff News Editor at Journal of Technology -- Hitachi, Ltd. (Tokyo, JP) has been issued patent number 8819675, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Uehara, Keitaro (Kokubunji, JP); Tsushima, Yuji (Hachioji, JP).

This patent was filed on August 5, 2008 and was published online on August 26, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "With a progress of a semiconductor technology in recent years, a multicore processor integrating a plurality of cores on one die, or a memory controller integrated processor mounting a memory controller on a processor die has appeared. In order to effectively utilize computer resources integrated in this way, a movement of reducing cost by integrating processings dispersed to a plurality of servers in a background art to one server is frequently observed. Means which becomes effective in integrating servers in this way is a method of operating a plurality of operating systems on one piece of server by server division. In server division, there are a physical division system of supporting division by hardware by a node unit, or a component unit of a processor (core) or I/O device, and a logical division system realized by a firmware referred to as a hypervisor or virtual machine monitor.

"According to the logical division system, respective operating systems (guest OS) are executed on a logical processor provided by a virtual machine monitor, and by mapping a plurality of logical processors to a physical processor by the virtual machine monitor, a section can be divided to a unit finer than a node. Further, with regard to the processor (core), the respective operating systems can also be executed while switching one physical processor (core) among a plurality of logical sections by time sharing. Thereby, a number of logical sections the number of which is larger than the number of the physical processors (cores) can be formed to simultaneously be executed. As virtual machine monitor software constituting an object by logical division, a technology described in U.S. Pat. No. 6,496,847 is representative.

"However, in comparison with a processor or a memory in which highly integrated formation is comparatively easy, with regard to I/O device which is essentially difficult to be integrated since it is necessary to provide a port (path) of input/output, a number thereof cannot be reduced and a tendency of deteriorating a balance between CPU and I/O device of the background art is observed. In order to increase a number of I/O devices, a countermeasure of increasing slots by using I/O switches is conceivable. However, by increasing a distance between a processor or a memory and I/O device by I/O switch, there is brought about a case in which I/O function cannot sufficiently be extracted.

"Hence, approach of ensuring a sufficient I/O function by making I/O device shared by a plurality of virtual servers in the background art exclusive for a specific virtual server has been adopted. As a function of supporting to make I/O device exclusive by virtual server in this way, VT-d established by Intel corp. or the like is known as disclosed in Intel Virtualization Technology for Directed I/O Architecture Specification [online], Intel Corp., searched on Aug. 24, 2007, internet (r)_VT_for_Direct_IO.pdf>.

"On the other hand, by progress of multicore formation or an appearance of a processor integrated with a memory controller, there is a tendency that an arrangement of resources of processors, memories, I/O devices becomes unbalanced. In order to ensure a function and reliability on such an unbalanced system, a distribution of resources using physical position information is needed. According to OS of the background art, there is a device referred to as Affinity control of corresponding specific processor and memory and in order to support the control, as a standard interface for acquiring physical position information, ACPI (Advanced Configuration and Power Interface) is rectified (Advanced Configuration and Power Interface Specification Revision 3.0, [online], Hewlett-Packard, Intel, Microsoft, Phoenix, and Toshiba, searched on Aug. 24, 2007, internet . According to the affinity control, resource are allocated by relating which CPU and memory OS or application uses."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "However, according to OS of the background art as described above, position information of processor and memory can be controlled by using the device of ACPI. However, I/O device is a resource commonly referred to from all applications, and therefore, a concept of the affinity control using the physical position information of I/O device is not present. Actually, in System Resource Affinity Table (SRAT) or System Locality Distance Information Table (SLIT) rectified in SCPI, only the physical information of processor and memory constitutes an object and physical position information of I/O device is out of the object.

"On the other hand, when I/O device is allocated to be exclusive for a specific virtual server by using a virtual machine monitor, the physical position information of I/O device becomes a parameter important for ensuring function or reliability of the virtual server. However, in the ACPI base interface of the background art, there is not means for acquiring the physical position information of I/O.

"Further, even when the virtual machine monitor assumedly allocates a pertinent resource to the virtual server, in a case in which guest OS on the virtual server cannot correctly utilize the physical position information, the Affinity control of guest OS is not correctly operated, as a result, there poses a problem that the function or the reliability equivalent to that of the physical server cannot be ensured.

"It is an object of the invention to provide an interface acquiring physical position information of I/O device on a virtual machine monitor having an exclusive allocation function of I/O device and optimize allocation of a resource to a virtual server by using the acquired physical position information in accordance with a designated policy. Further, it is an object thereof to provide an interface of pertinently converting physical position information acquired by a virtual machine monitor to notice to a virtual server and making an affinity control similar to that when guest OS is executed on a physical server executable also for guest OS on a virtual server.

"The invention is a multiprocessor system comprising a virtual machine monitor for connecting one or more processors, one or more memories, and one or more I/O devices by an internal network and allocating the processor, the memory, and the I/O device to a virtual server, wherein the virtual machine monitor comprises a physical hardware information acquiring portion for acquiring constitution information of a hardware including physical position information of the hardware including the processor, the memory, the I/O device, and the network of the multiprocessor system, a receiving portion for receiving a forming request including a number of the processors, an amount of the memory and the I/O device of the formed virtual server and a policy of allocating a resource, and an allocation processing portion for allocating the processor and the memory to the virtual server to satisfy the allocation policy after allocating the I/O device to the virtual server based on the received forming request.

"Further, the virtual machine monitor further comprises a noticing portion for noticing physical position information of the processor, the memory, and the I/O device allocated to the virtual server to the virtual server.

"Therefore, the invention can optimize to allocate the resource to the virtual server in accordance with the policy of allocating the resource designated by the forming request by acquiring the physical position information of the I/O device and using the acquired physical position information.

"Further, by noticing the physical position information of the resource allocated by the virtual machine monitor to the virtual server, a control similar to that on a physical server can be realized on the virtual server."

For the URL and additional information on this patent, see: Uehara, Keitaro; Tsushima, Yuji. Virtual Machine Monitor and Multiprocessor System. U.S. Patent Number 8819675, filed August 5, 2008, and published online on August 26, 2014. Patent URL:

Keywords for this news article include: Hitachi, Hitachi Ltd., Technology.

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Source: Journal of Technology

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