Oracle America, Inc.

David A Jurgens

Seth T Proctor

David R Chase

James Megquier

A system provides a task scheduler to define a priority queue with at least one window and a queue-window key. Each window is an ordered collection of tasks in a task pool of the priority queue and is identified by the queue-window key. The task scheduler sets a task-window key equal to a user-window key when the user-window key is greater than the minimum queue-window key. The task scheduler can further set the task-window key equal to the minimum queue-window key when the user-window key is less than the minimum queue-window key. A maximum task limit per user for each window and a priority increment for the user-window key are further applied to ensure fair scheduling.

Methods and apparatus for window-based fair priority scheduling

One embodiment may estimate the processing time of tasks requested by an application by maintaining a state-model for the application. The state model may include states that represent the tasks requested by the application, with each state including the average run-time of each task. In another embodiment, a state model may estimate which task is likely to be requested for processing after the current task is completed by providing edges in the state model connecting the states. Each edge in the state model may track the number of times the application transitions from one task to the next. Over time, data may be gathered representing the percentage of time that each edge is from a state node. Given this information, the scheduler may estimate the CPU cost of the next task based on the current state, the most likely transition, and the cost of the predicted next task. The state model may also track multiple users of the application and modify or create the state model as the users traverse through the state model.

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Los Angeles, CA, United States of America

David A Jurgens