Opportunistic Multitasking

• US 20110252429A1
• Filed: 12/02/2010
• Published: 10/13/2011
• Est. Priority Date: 04/07/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Forstall, Scott, Marcellino, Christopher, Srisuwananukorn, Charles, Ballard, Lucia, Goodwin, David W., Crane, Neil G., Watson, Matthew G., Sokol, Joseph Jr., Masputra, Cahya, Novick, Gregory
• Granted Patent: US 9,135,059 B2
• Time in Patent Office: Days
• US Class Current: 718/103
• CPC Class Codes: G06F 9/485 Task life-cycle, e.g. stopping, restarting, resuming execution G06F9/4881 takes precedence
• CPC Class Codes: G06F 9/5011 the resources being hardware resources other than CPUs, Servers and Terminals
• CPC Class Codes: G06F 9/542 Event management; Broadcasting; Multicasting; Notifications

Abstract

Services for a personal electronic device are provided through which a form of background processing or multitasking is supported. The disclosed services permit user applications to take advantage of background processing without significant negative consequences to a user'"'"'s experience of the foreground process or the personal electronic device'"'"'s power resources. To effect the disclosed multitasking, one or more of a number of operational restrictions may be enforced. By way of example, thread priority levels may be overlapped between the foreground and background states. In addition, system resource availability may be restricted based on whether a process is receiving user input. In some instances, an application may be suspended rather than being placed into the background state. Implementation of the disclosed services may be substantially transparent to the executing user applications and, in some cases, may be performed without the user application'"'"'s explicit cooperation.

Claims

1. A method to schedule processing in a limited multitasking operating system, comprising:

scheduling a first foreground process with a scheduling priority from a first band of priority levels; and

scheduling a first background process with a scheduling priority from a second band of priority levels, wherein the priority levels in the first band and the second band overlap by one, but not all, priority levels.

2. The method of claim 1, further comprising scheduling a third process with a priority from a real-time priority band, wherein all priority levels in the real-time priority band are greater than all priority levels in the first band.

3. The method of claim 2, wherein the act of scheduling a third process comprises scheduling a background process.

4. A multitasking method, comprising:

identifying a first user application executing in foreground state and receiving user input;

identifying a second user application executing in the foreground state and not receiving user input;

limiting the second foreground application'"'"'s access to one or more specified system resources because the second foreground application is not receiving user input.

5. The method of claim 4, wherein the one or more specified system resources are selected from the group consisting of:

camera, graphics processing unit, accelerometer, proximity sensor and microphone.

6. The method of claim 4, wherein the act of limiting the second foreground application'"'"'s access to one or more specified system resources comprises reporting a smaller than actual incoming network buffer size to a distal source.

7. A program storage device, readable by a programmable control device, comprising instructions stored thereon for causing the programmable control device to perform a method in accordance with claim 4.

8. A multitasking method, comprising:

identifying a first user application executing in a foreground state;

receiving user input directing that a second user application is to be placed into the foreground state;

suspending only the first user application in response to the received user input; and

placing the second user application into the foreground state.

9. The method of claim 8, wherein the act of suspending is performed only if the first user application has not identified itself as an application that can execute in background.

10. The method of claim 8, further comprising:

receiving a message for the suspended first user application;

moving the suspended first user application into a background state; and

providing the message to the first user application in background.

11. A program storage device, readable by a programmable control device, comprising instructions stored thereon for causing the programmable control device to perform a method in accordance with claim 8.