Removal of idle time in virtual machine operation

• US 9,323,576 B2
• Filed: 02/04/2014
• Issued: 04/26/2016
• Est. Priority Date: 02/04/2014
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Hotra, Jonathan N., Esrig, Jerry A.
• Primary Examiner(s): Tang, Kenneth
• Application Number:
  US14/172,206
• Publication Number:
  US 20150220367A1
• Time in Patent Office: 812 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 2009/4557 Distribution of virtual machine instances; Migration and load balancing
• CPC Class Codes: G06F 2209/508 Monitor
• CPC Class Codes: G06F 9/45533 Hypervisors; Virtual machine monitors
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects
• CPC Class Codes: G06F 9/4825 Interrupt from clock, e.g. time of day
• CPC Class Codes: G06F 9/4887 involving deadlines, e.g. rate based, periodic
• CPC Class Codes: G06F 9/5038 considering the execution order of a plurality of tasks, e.g. taking priority or time dependency constraints into consideration scheduling strategies G06F9/4881 and subgroups

Abstract

A computer system for providing virtualization services may execute computer programs by a virtual processor in a virtual machine. The computer programs may be executed as tasks scheduled for execution at respective points in an apparent time tracked by an apparent-time reference. During execution of the computer programs, the computer system may detect a current point in apparent time at which all tasks scheduled for repeated execution at a given frequency have been executed, or at which the virtual processor is idle. And in response, the computer system may advance the apparent time to a subsequent point with a frequency greater than that with which the apparent time is tracked by the apparent-time reference.

Claims

1. A computer system comprising a processor and a memory storing computer-readable program code portions that, in response to execution by the processor, cause the computer system to at least:

execute one or more computer programs by a virtual processor in a virtual machine, the computer programs being executed as tasks scheduled for execution at respective points in an apparent time tracked by an apparent-time reference; and

during execution of the computer programs;

detect a current paint, in apparent time at which all tasks scheduled for repeated execution at a given frequency have been executed, or at which the virtual processor is idle and in response thereto,

advance the apparent time from the current point to a subsequent point with a frequency greater than that with which the apparent time is tracked by the apparent-time reference,

wherein the computer programs are executed as tasks during a cycle divided into a plurality of frames in one or more of which each of at least some of the tasks is scheduled for execution, and the apparent-time reference comprises a virtual timer configured to track the frames having boundaries defined at respective points in the apparent time,

wherein the computer system being, caused to detect the current point in apparent time includes being caused to detect the current point in apparent time during any particular frame at which the virtual processor is idle, and

wherein the computer system being caused to advance the apparent time includes being caused to advance the apparent time to the subsequent point in apparent time that defines the boundary of a frame immediately following the particular frame in the cycle, such that idle time in the system may be removed to provide an improvement in performance of the virtual processor.

3. The computer system of claim 1, wherein the computer system being caused to detect the current point includes being caused to detect the current point in apparent time at which the virtual processor is idle, and

wherein the computer system being caused to advance the apparent time includes being, caused to incrementally advance the apparent time in portions of a duration of each of the frames until the earlier of the subsequent point in apparent time that defines the boundary of a frame immediately following the particular frame in the cycle, or the subsequent point in apparent time at which a task is scheduled for execution.

4. The computer system of claim 1, wherein the subsequent point in apparent time is the point in apparent time that defines the boundary of a frame immediately following the particular frame in the cycle, less a processing, window of a given duration of the particular frame, and wherein during execution of the computer programs, the computer system is further caused to:

detect a current point in apparent time during the processing window at which all tasks scheduled for repeated execution at a given frequency have been executed, or at which the virtual processor is idle; and

in response thereto,

advance the apparent time from the current point to the subsequent point in apparent time that defines the boundary of the frame immediately following the particular frame in the cycle.

5. The computer system claim 1, wherein the apparent-time reference is configured to virtualize a corresponding time reference of a target hardware platform, and the tasks are generated in response to events known to occur at respective points in apparent time, the events including events that occur at the respective points in apparent time at which the boundaries of the frames are defined,

wherein the computer system being caused to detect the current point includes being caused to detect the current point in apparent time at which the virtual processor is idle, and

wherein the computer system being caused to advance the apparent time includes being caused to advance the apparent time to a next subsequent point in apparent time at which an event of the events is known to occur.

6. The computer system of claim 1, wherein the computer system is caused to detect the current point in apparent time, and advance the apparent time fro the current point, at or within the virtual machine.

2. The computer system of claim wherein the virtual machine is defined to provide a virtualization platform for virtualization of a target hardware platform including a processor of a type different from the processor of the computer system, the virtualization platform including the virtual processor configured to execute the computer programs through emulation of the processor of the target hardware platform.

7. A method of providing virtualization services, the method comprising:

executing one or MOM computer programs by a virtual processor in a virtual machine, the computer programs being executed as tasks scheduled for execution at respective points in an apparent time tracked by an apparent-time reference; and

during execution of the computer programs;

detecting a current point in apparent time at which all tasks scheduled for repeated execution at a given frequency have been executed, or at which the virtual processor is idle; and

in response thereto, advancing the apparent time from the current point to a subsequent point with a frequency greater than that with which the apparent time is tracked by the apparent-time reference,

wherein the computer programs are executed as tasks during a cycle divided into t pluarlity of frames in one or more of which each of at least some of the tasks is scheduled for execution, and the a rent-time reference comprise a virtual timer configure to track the flames having boundaries defined at respective points in the apparent time,

wherein detecting the current point in apparent time includes detecting the current point in apparent time during any particular frame at which the virtual processor is idle,

wherein advancing the apparent time includes advancing the apparent time to the subsequent point in apparent time that defines the boundary of a frame immediately following the particular frame in the cycle, such that de time may he removed to provide an improvement in performance of the virtual processor, and

wherein the virtualization services are provided by computer system comprising a processor and a memory storing computer-readable program code portions that, in response to execution by the processor, cause the computer system to execute the computer programs, detect the current point in apparent time and advance the apparent time from the current point.

8. The method of claim 7, wherein detecting the current point includes detecting the current point in apparent time at which the virtual processor is idle, and

wherein advancing the apparent time includes incrementally advancing the apparent time in portions of a duration of each of the frames until the earlier of the subsequent point in apparent time that defines the boundary of a frame immediately following the particular frame in the cycle, or the subsequent point in apparent time at which a task is scheduled for execution.

9. The method of claim 7, wherein the subsequent point in apparent time is the point in apparent time that defines the boundary of a frame immediately following the particular frame in the cycle, less a processing window of a given duration of the panieular frame.

10. The method of claim 9, wherein during execution of the computer programs, the method further includes:

detecting a current point in apparent time during the processing window at which all tasks scheduled for repeated execution at a given frequency have been executed, or at which the virtual processor is idle; and

in response thereto,

advancing the apparent time from the current point to the subsequent point in apparent time that defines the boundary of the frame immediately following the particular frame in the cycle.

11. The method of claim 7, wherein the apparent-time reference is configured to virtualize a corresponding time reference of a target hardware platform, and the tasks are generated in response to events known to occur at respective points in apparent time, the events including events that occur at the respective points in apparent time at which the boundaries of the frames are defined,

wherein detecting the current point includes detecting the current point in apparent time at which the virtual processor is idle, and

wherein advancing the apparent time includes advancing the apparent time to a next subsequent point in apparent time at which an event of the events is known to occur.

12. A computer-readable storage medium having computer-readable program code portions stored therein that, in response to execution by a processor, cause a computer system to at least:

execute one or more computer programs by a virtual processor in a virtual machine, the computer programs being executed as tasks scheduled for execution at respective points in an apparent time tracked by an apparent-time reference; and

during execution of the computer programs;

detect a current point in apparent time at which all tasks scheduled for repeated execution at a given frequency have been executed, or at which the virtual processor is idle; and

in response thereto,

advance the apparent time from the current point to a subsequent point with it frequency greater than that with which the apparent time is tracked by the apparent-time reference,

wherein the computer programs are executed as tasks during a cycle divided into a plurality of frames in one or more of which each of at least some of the tasks is scheduled for execution. and the apparent-time re retire comprises a virtual timer configured to track the frames having boundaries defined at respective points in the apparent time,

wherein the computer system being, caused to detect the current point in apparent time includes being caused to detect the current point in apparent time during any particular frame at which the virtual processor is idle, and

wherein the computer system being caused to advance the apparent time includes being caused to advance the apparent time to the subsequent point in apparent time that defines the boundary of a frame immediately following the particular frame in the cycle, such that idle time in the system max be removed to provide an improvement in performance of the virtua1 processor.

13. The computer-readable storage medium of claim 12, wherein the computer system being caused to detect the current point includes being caused to detect the current point in apparent time at which the virtual processor is idle, and

wherein the computer system being caused to advance the apparent time includes being caused to incrementally advance the apparent time in portions of a duration of each of the frames until the earlier of the subsequent point in apparent time that defines the boundary of a frame immediately following the particular frame in the cycle, or the subsequent point in apparent time at which a task is scheduled for execution.

14. The computer-readable storage medium of claim 12, wherein the subsequent point in apparent time is the point in apparent time that defines the boundary of a frame immediately following the particular frame in the cycle, less a processing window of a given duration of the particular frame, and wherein during execution of the computer programs, the computer system is further caused to:

detect a current paint in apparent time during the processing window at which all tasks scheduled for repeated execution at a given frequency have been executed, or at which the virtual processor is idle; and

in response thereto,

advance the apparent time from the current point to the subsequent point in apparent time that defines the boundary of the frame immediately following the particular frame in the cycle.

15. The computer-readable storage medium of claim 12, wherein the apparent-time reference is configured to virtualize a corresponding, time reference of a target hardware platform, and the tasks are generated in response to events known to occur at respective paints in apparent time, the events including events that occur at the respective points in apparent time at which the boundaries of the frames are defined,

wherein the computer system being caused to detect the current point includes being caused to detect the current point in apparent time at which the virtual processor is idle, and

wherein the computer system being caused to advance the apparent time includes being caused to advance the apparent time to a next subsequent point in apparent time at which an event of the events is known to occur.