US Patent 9135059 Opportunistic multitasking

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.