The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 03, 2012
Filed:
Aug. 04, 2011
Toshiomi Moriki, Kokubunji, JP;
Keitaro Uehara, Kokubunji, JP;
Yuji Tsushima, Hachioji, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Arbitration of IO accesses and band control based on the priority of virtual servers is enabled while curbing performance overhead during IO sharing among the virtual servers. A virtual machine system includes a CPU, a memory, a hypervisor that generates plural virtual servers, and an IO controller that controls an IO interface. The IO controller includes: a DMA receiving unit that receives DMA requests from the IO interface; a decoder that decodes received DMA requests and locates the corresponding virtual servers; a DMA monitoring counter that monitors DMA processing status for each of the virtual servers; a threshold register set in advance for each of the virtual servers; and a priority deciding unit that compares the DMA monitoring counter and the value of the threshold register, and based on processing priority obtained as a result of the comparison, decides the priority of processing of the received DMA requests.