| 摘要 |
PURPOSE: An extended task scheduling algorithm is provided to effectively reduce an execution time delay of an XIP(eXecute In Place) program under a multiprocessing OS(Operating System), for example, an embedded Linux OS(Operating System) so that it can enhance a system performance. CONSTITUTION: The algorithm comprises steps of determining if a task, selected by a task scheduling algorithm, is normally executed in a given execution environment, changing the execution environment in a case that a corresponding task is not normally executed, completing normally the corresponding task and recovering the task execution environment. The step of determining a normal execution of the selected task includes steps of determining if the task, selected by the task scheduling algorithm, is an XIP task, determining if a read operation can be performed at a flash memory in a case that the task is an XIP task, and determining if a regeneration process of the flash memory can be delayed in a case that the read operation can not be performed at the flash memory. The step of changing the execution environment includes steps of temporarily stopping a regeneration process of the flash memory and executing the corresponding XIP task in a case that the regeneration process can be delayed, and copying an execution image of the task at the flash memory, erasing an existing page table, and executing the task at a main memory in a case that the regeneration process can not be delayed. The step of recovering the task execution environment includes steps of restarting the regeneration process of the flash memory in a case that a system setting is changed, and erasing an execution image of the copied XIP task from the main memory and erasing the page table in a case that the regeneration process is completed.
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