Systems and methods for weighted best effort scheduling

A network processor for processing packets of data, comprising:

• a data flow unit to receive packets of data, and for each packet, to determine a flow queue to which the packet belongs, and to transmit processed packets;
• an embedded processors complex comprising a plurality of processors to process packet data;
• a memory to store schedule control blocks in a first, second, and third linked list, each schedule control block associated with a weight and comprising a counter;
• first, second, and third calendar entries associated with the first, second, and third linked lists, respectively, each calendar entry adapted to store an address for a first-out schedule control block in the linked-list of schedule control blocks associated with the calendar entry;
• control circuitry to increment a counter of a first-out schedule control block from one of the first or second linked lists;
• and to move the first-out schedule control block from the one linked list to the other of the first and second linked lists if the incremented counter is less than the weight, and to move the first-out schedule control block from the one linked list to the third linked list if the incremented counter equals or exceeds the weight.

A method for scheduling packets of data in a network processor, comprising:

• storing schedule control blocks in linked lists, each schedule control block associated with a queue and assigned a weight associated with a scheduling priority for the queue;
• sequentially accessing each schedule control block stored in a first linked list;
• sequentially accessing each schedule control block stored in a second linked list;
• generating a scheduling event for the packet corresponding to an accessed schedule control block for each schedule control block accessed from the first or second linked list;
• incrementing a counter in a schedule control block each time a schedule control block is accessed from the first or second linked lists;
• comparing the counter of the accessed schedule control block each time a schedule control block is accessed to the weight assigned to the schedule control block;
• transferring a schedule control block from one of the first and second linked lists to the other of the first and second linked list, if the compared counter value is less than the weight assigned to the schedule control block;
• and
• transferring a schedule control block from one of the first and second linked lists to a third linked list and resetting the counter of the schedule control block, if the compared counter value equals or exceeds the weight assigned to the schedule control block.