| 摘要 |
A method, apparatus and computer program product are provided for implementing multiple credit levels generated over multiple queues for a dataflow. A plurality of programmable configuration values is stored for each of the multiple queues including a queue maximum count, a queue clip count and a queue cutoff count. Buffer use and a number of outstanding credits to the dataflow for each of the multiple queues are monitored to maintain a current in use count. The current in use count is compared with a programmable global threshold count and the queue cutoff counts of the multiple queues. A number of credits are selectively generated for each of the multiple queues based upon the compared counts and the stored programmable configuration values. Different values are set for the queue cutoff counts of the multiple queues to set a priority of each queue. When the current in use count is less than the programmable global threshold count, a respective first number of credits are generated based upon the queue maximum count for each of the multiple queues. When the current in use count is greater than the programmable threshold count and less than the queue cutoff count, a respective second number of credits are generated based upon the queue clip count. When the current in use count is greater than the queue cutoff count for a queue, zero credits are generated for the queue. The stored programmable configuration values for each of the multiple queues include a queue threshold count. A current number of outstanding credits are maintained for each of the multiple queues. The queue threshold count is compared with the current number of outstanding credits for each of the multiple queues. When the current number of outstanding credits is greater than the queue threshold count for a queue, zero credits are generated for the queue.
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