A work conserving scheduler can be implemented based on a ranking system to provide the scalability of time stamps while avoiding the fast search associated with a traditional time stamp implementation. Each queue can be assigned a time stamp that is initially set to zero. The time stamp for a queue can be incremented each time a data packet from the queue is processed. To provide varying weights to the different queues, the time stamp for the queues can be incremented at varying rates. The data packets can be processed from the queues based on the tier rank order of the queues as determined from the time stamp associated with each queue. To increase the speed at which the ranking is determined, the ranking can be calculate from a subset of the bits defining the time stamp rather than the entire bit set.

A system and method for maintaining information of pending operations are described. A buffer uses multiple linked lists implementing a single logical queue for a single requestor. The buffer maintains multiple head pointers and multiple tail pointers for the single requestor. Data entries of the single logical queue are stored in an alternating pattern among the multiple linked lists. During the allocation of buffer entries, the tail pointers are selected in the same alternating manner, and during the deallocation of buffer entries, the multiple head pointers are selected in the same manner.

Multiple listlets function as a single master linked list to manage data packets across one or more banks of memory in a first-in first-out (FIFO) order, while allowing multiple push and/or pop functions to be performed per cycle. Each listlet can be a linked list that tracks pointers and is stored in a different memory bank. The nodes can include a pointer to a data packet, a pointer to the next node in the listlet and a next listlet identifier that identifies the listlet that contains the next node in the master linked list. The head and tail of each listlet, as well as an identifier each to track the head and tail of the master linked list, can be maintained in cache. The individual listlets are updated accordingly to maintain order of the master linked list as pointers are pushed and popped from the master linked list.

An out of order processor. The processor includes a virtual load store queue for allocating a plurality of loads and a plurality of stores, wherein more loads and more stores can be accommodated beyond an actual physical size of the load store queue of the processor; wherein the processor allocates other instructions besides loads and stores beyond the actual physical size limitation of the load/store queue; and wherein the other instructions can be dispatched and executed even though intervening loads or stores do not have spaces in the load store queue.

A multicast rule is represented in a hierarchical linked list with N tiers. Each tier or level in the hierarchical linked list corresponds to a network layer of a network stack that requires replication. Redundant groups in each tier are eliminated such that the groups in each tier are stored exactly once in a replication table. A multicast replication engine traverses the hierarchical linked list and replicates a packet according to each node in the hierarchical linked list.

This application provides a link management method. The physical device includes a first memory that stores a tail pointer of a link and a second memory that stores a head pointer of the link, and the physical device supports one time of enqueue processing and one time of dequeue processing in one clock cycle. The method includes: when a first link is not empty before the enqueue processing, modifying, by the physical device, a first tail pointer that is of the first link and that is in the first memory; and when a second link is not empty after the dequeue processing, modifying, by the physical device, a second head pointer that is of the second link and that is in the second memory.

A memory system for a network device is described. The memory system includes a main memory configured to store one or more data elements. Further, the memory system includes a link memory that is configured to maintain one or more pointers to interconnect the one or more data elements stored in the main memory. The memory system also includes a free-entry manager that is configured to generate an available bank set including one or more locations in the link memory. In addition, the memory system includes a context manager that is configured to maintain metadata for a list of the one or more data elements.

An out of order processor. The processor includes a distributed load queue and a distributed store queue that maintain single program sequential semantics while allowing an out of order dispatch of loads and stores across a plurality of cores and memory fragments; wherein the processor allocates other instructions besides loads and stores beyond the actual physical size limitation of the load/store queue; and wherein the other instructions can be dispatched and executed even though intervening loads or stores do not have spaces in the load store queue.

Multiple listlets function as a single master linked list to manage data packets across one or more banks of memory in a first-in first-out (FIFO) order, while allowing multiple push and/or pop functions to be performed per cycle. Each listlet can be a linked list that tracks pointers and is stored in a different memory bank. The nodes can include a pointer to a data packet, a pointer to the next node in the listlet and a next listlet identifier that identifies the listlet that contains the next node in the master linked list. The head and tail of each listlet, as well as an identifier each to track the head and tail of the master linked list, can be maintained in cache. The individual listlets are updated accordingly to maintain order of the master linked list as pointers are pushed and popped from the master linked list.

A memory system for a network device is described. The memory system includes a main memory configured to store one or more data elements. Further, the memory system includes a link memory that is configured to maintain one or more pointers to interconnect the one or more data elements stored in the main memory. The memory system also includes a free-entry manager that is configured to generate an available bank set including one or more locations in the link memory. In addition, the memory system includes a context manager that is configured to maintain metadata for a list of the one or more data elements.