Real-time performance apparatus and method for controlling virtual machine scheduling in real-time

A hardware apparatus to control a virtual machine schedule time, the apparatus comprising:

• hardware configured to execute a plurality of virtual machines;
• a process scheduler configured to schedule processes to be executed by the plurality of virtual machines using a process schedule time at which a process is invoked or switched;
• and
• a virtual machine monitor configured to provide a virtualized execution environment, atop the hardware, to each of the plurality of virtual machines, the virtual machine monitor comprising:
• a virtual machine scheduler configured to schedule execution of each of the plurality of virtual machines on the hardware using a virtual machine schedule time at which a virtual machine of the plurality of virtual machines is invoked or switched with another virtual machine of the plurality of virtual machines;
• and
• a schedule time control unit configured to:
• change the virtual machine schedule time based on the process schedule time of the virtual machine of the plurality of virtual machines, in response to determining that a process being executed has not been executed for at least a first reference amount of time;
• postpone the virtual machine schedule time of a next virtual machine of the plurality of virtual machines by an amount of time to synchronize a process schedule time of the next virtual machine with another virtual machine of the plurality of virtual machines based on detected synchronization information, in response to determining that a process of the another virtual machine will not be executed within a second reference amount of time;
• and
• define a hypercall which is transferred from a currently executing virtual machine and detect a process switch to a real-time process through the hypercall in response to scheduling occurring in the currently executing virtual machine, and increase an execution time of the currently executing virtual machine by a delay time while the currently executing virtual machine is executing the real-time process, in response to determining that a difference between a present time value and a time value at which the real-time process is scheduled is less than a minimum execution time of the real-time process.

A method of controlling a virtual machine schedule time using hardware configured to execute a plurality of virtual machines, the method comprising:

• scheduling, by a process scheduler, processes to be executed by the plurality of virtual machines using a process schedule time at which a process is invoked or switched;
• and
• providing, by a virtual machine monitor, a virtualized execution environment, atop the hardware, to each of the plurality of virtual machines, wherein the providing of the virtualized execution environment comprises:
• scheduling, by a virtual machine scheduler, execution of each of the plurality of virtual machines on the hardware using a virtual machine schedule time at which a virtual machine of the plurality of virtual machines is invoked or switched with another virtual machine of the plurality of virtual machines;
• and
• scheduling, by a schedule time control unit, by:
• changing the virtual machine schedule time based on the process schedule time of a virtual machine of the plurality of virtual machines, in response to determining that a process being executed has not been executed for at least a first reference amount of time;
• postponing the virtual machine schedule time of a next virtual machine of the plurality of virtual machines by an amount of time to synchronize a process schedule time of the next virtual machine with another virtual machine of the plurality of virtual machines based on detected synchronization information, in response to determining that a process of the another virtual machine will not be executed within a second reference amount of time;
• and
• defining a hypercall which is transferred from a currently executing virtual machine and detecting a process switch to a real-time process through the hypercall in response to scheduling occurring in the currently executing virtual machine, and increasing an execution time of the virtual machine by a delay time while the currently executing virtual machine is executing the real-time process, in response to determining that a difference between a present time value and a time value at which the real-time process is scheduled is less than a minimum execution time of the real-time process.

A method of controlling a virtual machine schedule time using hardware configured to execute a plurality of virtual machines, the method comprising:

• before a beginning of a virtual machine schedule, determining whether to delay a virtual machine schedule time by an amount of time based on execution of a real-time process within a first time period or transmission of an interrupt to a currently executing virtual machine within a second time period;
• in response to the virtual machine schedule time being delayed, determining whether the execution of the real-time process has terminated, or the time has been reached;
• scheduling, by a process scheduler, processes to be executed by the plurality of virtual machines using a process schedule time at which a process is invoked or switched;
• and
• providing, by a virtual machine monitor, a virtualized execution environment, atop the hardware, to each of the plurality of virtual machines, wherein the providing of the virtualized execution environment comprises:
• scheduling, by a virtual machine scheduler, execution of each of the plurality of virtual machines on the hardware using a virtual machine schedule time at which a virtual machine of the plurality of virtual machines is invoked or switched with another virtual machine of the plurality of virtual machines;
• and
• scheduling, by a schedule time control unit, by:
• changing the virtual machine schedule time based on the process schedule time of a virtual machine of the plurality of virtual machines, in response to determining that a process being executed has not been executed for at least a first reference amount of time;
• postponing the virtual machine schedule time of a next virtual machine of the plurality of virtual machines by an amount of time to synchronize a process schedule time of the next virtual machine with another virtual machine of the plurality of virtual machines, in response to determining that a process of the another virtual machine will not be executed within a second reference amount of time;
• and
• defining a hypercall which is transferred from a currently executing virtual machine and detecting a process switch to a real-time process through the hypercall in response to scheduling occurring in the currently executing virtual machine, and increasing an execution time of the virtual machine by a delay time while the currently executing virtual machine is executing the real-time process, in response to determining that a difference between a present time value and a time value at which the real-time process is scheduled is less than a minimum execution time of the real-time process.