In case anyone else is wondering a "ring" is a queue data structure which provides a different set of trade-offs. The documentation specifically compares it to

In case anyone else is wondering a "ring" is a queue data structure which provides a different set of trade-offs. The documentation specifically compares it to a linked list: The advantages of this data structure over a linked list queue are as follows: * Faster; only requires a single Compare-And-Swap instruction of sizeof(void *) instead of several double-Compare-And-Swap instructions. * Simpler than a full lockless queue. * Adapted to bulk enqueue/dequeue operations. As pointers are stored in a table, a dequeue of several objects will not produce as many cache misses as in a linked queue. Also, a bulk dequeue of many objects does not cost more than a dequeue of a simple object. The disadvantages: * Size is fixed * Having many rings costs more in terms of memory than a linked list queue. An empty ring contains at least N pointers. http://dpdk.org/doc/guides/prog_guide/ring_lib.html http://dpdk.org/doc/guides/prog_guide/ring_lib.html