Patent ID: 8146081

Claim:
A method of switching an execution schedule of a plurality of guest operating systems (OSes) in a virtual machine system in which the plurality of guest OSes are time-divisionally executed under virtual machine execution environments provided by a virtual machine monitor, any two of the plurality of guest OSes executing processing while intercommunicating with each other via a communication interface that is provided by the virtual machine monitor, the method comprising: specifying a group of guest OSes which intercommunicate with each other via the communication interface, by the virtual machine monitor; setting a first quantum in an execution schedule of each of the guest OSes included in the specified group of guest OSes shorter by the virtual machine monitor; controlling repetition of both the specifying and the setting by the virtual machine monitor, the repetition being performed at predetermined schedule time periods; computing a first average communication time by the virtual machine monitor each time the group of guest OSes is specified, the first average communication time being a current average communication time required for intercommunications between the guest OSes of the specified group of guest OSes; and comparing the first average communication time with a second average communication time by the virtual machine monitor, the second average communication time being computed when a quantum is set one-scale longer than a second quantum which has been set when the first average communication time is computed, wherein the first quantum is set one-scale shorter than the second quantum if the first average communication time is shorter than the second average communication time, and the first quantum is set one-scale longer than the second quantum if the first average communication time is not shorter than the second average communication time.