Weighted fair queue having extended effective range

Abstract

A scheduler for a network processor includes a scheduling queue in which weighted fair queuing is applied to define a sequence in which flows are to be serviced. The scheduling queue includes at least a first subqueue and a second subqueue. The first subqueue has a first range and a first resolution, and the second subqueue has an extended range that is greater than the first range and a lower resolution that is less than the first resolution. Flows that are to be enqueued within the range of highest precision to the current pointer of the scheduling queue are attached to the first subqueue. Flows that are to be enqueued outside the range of highest precision from the current pointer of the scheduling queue are attached to the second subqueue. Numerous other aspects are provided.

Description

[0001] The present application is a continuation of and claims priority from U.S. patent application Ser. No. 10 / 016,518, filed Nov. 1, 2001 which is hereby incorporated by reference herein in its entirety. CROSS REFERENCE TO RELATED PATENT APPLICATIONS [0002] The present application is related to the following U.S. patent applications, each of which is hereby incorporated by reference herein in its entirety: U.S. patent application Ser. No. 10 / 015,994, filed Nov. 1, 2001, titled “WEIGHTED FAIR QUEUE SERVING PLURAL OUTPUT PORTS” (IBM Docket No. ROC920010200US1); U.S. patent application Ser. No. 10 / 015,760, filed Nov. 1, 2001, titled “WEIGHTED FAIR QUEUE HAVING ADJUSTABLE SCALING FACTOR” (IBM Docket No. ROC920010201US1); U.S. patent application Ser. No. 10 / 002,085, filed Nov. 1, 2001, titled “EMPTY INDICATORS FOR WEIGHTED FAIR QUEUES” (IBM Docket No. ROC920010202US1); U.S. patent application Ser. No. 10 / 004,373, filed Nov. 1, 2001, titled “QoS SCHEDULER AND METHOD FOR IMPLEMENTIN...

AI Technical Summary

Benefits of technology

The present invention provides a scheduler for a network processor that includes one or more scheduling queues for servicing flows. The scheduling queues include a first subqueue and a second subqueue, with different ranges and resolutions. This allows for an enhanced range without adding to the total number of queue slots and provides high resolution. The scheduler also includes a method for dequeuing a flow from the scheduling queue. The technical effects of the invention include improved performance and efficiency of the network processor.

Problems solved by technology

However, this has disadvantages in terms of increased chip area, greater manufacturing cost and power consumption, and increased queue searching time.

However, if resolution is decreased, flows that should be assigned different priorities according to their respective QoS may appear to “tie” by being assigned to the same slot, thereby improperly being assigned essentially equal service priority.

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