Patent ID: 8539010

Claim:
A virtual machine, comprising: a computer including a memory, a processor, a timer and an input/output (I/O) device; and a virtual machine monitor to be loaded on the memory and executed by the processor, the virtual machine monitor controlling execution of at least one guest operating system (OS) on the processor, accepting a process request from the guest OS to the computer and handing over a result of execution made by the computer in response to the process request to the guest OS, wherein the virtual machine monitor makes the processor function as: a unit to receive a timer setting from the guest OS, the timer setting being for making the timer generate a timer interrupt after a lapse of a setting period; a timer changing unit to change the setting period set in the timer setting so that a ratio of first I/O wait time to first I/O process time other than the first I/O wait time becomes approximate to a ratio of second I/O wait time to second I/O process time, the first I/O wait time being time recognized by the guest OS as I/O wait time, time first I/O process time being time recognized by the guest OS as I/O process time, the second I/O wait time being time recognized by the virtual machine monitor as I/O wait time, and the second I/O process time being time recognized by the virtual machine monitor as I/O process time; a unit to set the timer setting with the changed setting period in the timer; and a unit to notify, when receiving the timer interrupt, the guest OS of occurrence of the timer interrupt.