[v4,2/5] ring: add a non-blocking implementation

Message ID 20190128181407.32739-3-gage.eads@intel.com
State New
Delegated to: Thomas Monjalon
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Series
  • Add non-blocking ring
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Commit Message

Eads, Gage Jan. 28, 2019, 6:14 p.m.
This commit adds support for non-blocking circular ring enqueue and dequeue
functions. The ring uses a 128-bit compare-and-swap instruction, and thus
is currently limited to x86_64.

The algorithm is based on the original rte ring (derived from FreeBSD's
bufring.h) and inspired by Michael and Scott's non-blocking concurrent
queue. Importantly, it adds a modification counter to each ring entry to
ensure only one thread can write to an unused entry.

-----
Algorithm:

Multi-producer non-blocking enqueue:
1. Move the producer head index 'n' locations forward, effectively
   reserving 'n' locations.
2. For each pointer:
 a. Read the producer tail index, then ring[tail]. If ring[tail]'s
    modification counter isn't 'tail', retry.
 b. Construct the new entry: {pointer, tail + ring size}
 c. Compare-and-swap the old entry with the new. If unsuccessful, the
    next loop iteration will try to enqueue this pointer again.
 d. Compare-and-swap the tail index with 'tail + 1', whether or not step 2c
    succeeded. This guarantees threads can make forward progress.

Multi-consumer non-blocking dequeue:
1. Move the consumer head index 'n' locations forward, effectively
   reserving 'n' pointers to be dequeued.
2. Copy 'n' pointers into the caller's object table (ignoring the
   modification counter), starting from ring[tail], then compare-and-swap
   the tail index with 'tail + n'.  If unsuccessful, repeat step 2.

-----
Discussion:

There are two cases where the ABA problem is mitigated:
1. Enqueueing a pointer to the ring: without a modification counter
   tied to the tail index, the index could become stale by the time the
   enqueue happens, causing it to overwrite valid data. Tying the
   counter to the tail index gives us an expected value (as opposed to,
   say, a monotonically incrementing counter).

   Since the counter will eventually wrap, there is potential for the ABA
   problem. However, using a 64-bit counter makes this likelihood
   effectively zero.

2. Updating a tail index: the ABA problem can occur if the thread is
   preempted and the tail index wraps around. However, using 64-bit indexes
   makes this likelihood effectively zero.

With no contention, an enqueue of n pointers uses (1 + 2n) CAS operations
and a dequeue of n pointers uses 2. This algorithm has worse average-case
performance than the regular rte ring (particularly a highly-contended ring
with large bulk accesses), however:
- For applications with preemptible pthreads, the regular rte ring's
  worst-case performance (i.e. one thread being preempted in the
  update_tail() critical section) is much worse than the non-blocking
  ring's.
- Software caching can mitigate the average case performance for ring-based
  algorithms. For example, a non-blocking ring based mempool (a likely use
  case for this ring) with per-thread caching.

The non-blocking ring is enabled via a new flag, RING_F_NB. Because the
ring's memsize is now a function of its flags (the non-blocking ring
requires 128b for each entry), this commit adds a new argument ('flags') to
rte_ring_get_memsize(). An API deprecation notice will be sent in a
separate commit.

For ease-of-use, existing ring enqueue and dequeue functions work on both
regular and non-blocking rings. This introduces an additional branch in
the datapath, but this should be a highly predictable branch.
ring_perf_autotest shows a negligible performance impact; it's hard to
distinguish a real difference versus system noise.

                                  | ring_perf_autotest cycles with branch -
             Test                 |   ring_perf_autotest cycles without
------------------------------------------------------------------
SP/SC single enq/dequeue          | 0.33
MP/MC single enq/dequeue          | -4.00
SP/SC burst enq/dequeue (size 8)  | 0.00
MP/MC burst enq/dequeue (size 8)  | 0.00
SP/SC burst enq/dequeue (size 32) | 0.00
MP/MC burst enq/dequeue (size 32) | 0.00
SC empty dequeue                  | 1.00
MC empty dequeue                  | 0.00

Single lcore:
SP/SC bulk enq/dequeue (size 8)   | 0.49
MP/MC bulk enq/dequeue (size 8)   | 0.08
SP/SC bulk enq/dequeue (size 32)  | 0.07
MP/MC bulk enq/dequeue (size 32)  | 0.09

Two physical cores:
SP/SC bulk enq/dequeue (size 8)   | 0.19
MP/MC bulk enq/dequeue (size 8)   | -0.37
SP/SC bulk enq/dequeue (size 32)  | 0.09
MP/MC bulk enq/dequeue (size 32)  | -0.05

Two NUMA nodes:
SP/SC bulk enq/dequeue (size 8)   | -1.96
MP/MC bulk enq/dequeue (size 8)   | 0.88
SP/SC bulk enq/dequeue (size 32)  | 0.10
MP/MC bulk enq/dequeue (size 32)  | 0.46

Test setup: x86_64 build with default config, dual-socket Xeon E5-2699 v4,
running on isolcpus cores with a tickless scheduler. Each test run three
times and the results averaged.

Signed-off-by: Gage Eads <gage.eads@intel.com>
---
 lib/librte_ring/rte_ring.c           |  72 ++++++--
 lib/librte_ring/rte_ring.h           | 313 +++++++++++++++++++++++++++++++----
 lib/librte_ring/rte_ring_c11_mem.h   | 282 ++++++++++++++++++++++++++++++-
 lib/librte_ring/rte_ring_generic.h   | 269 ++++++++++++++++++++++++++++++
 lib/librte_ring/rte_ring_version.map |   7 +
 5 files changed, 896 insertions(+), 47 deletions(-)

Patch

diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
index d215acecc..f3378dccd 100644
--- a/lib/librte_ring/rte_ring.c
+++ b/lib/librte_ring/rte_ring.c
@@ -45,9 +45,9 @@  EAL_REGISTER_TAILQ(rte_ring_tailq)
 
 /* return the size of memory occupied by a ring */
 ssize_t
-rte_ring_get_memsize(unsigned count)
+rte_ring_get_memsize_v1905(unsigned int count, unsigned int flags)
 {
-	ssize_t sz;
+	ssize_t sz, elt_sz;
 
 	/* count must be a power of 2 */
 	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
@@ -57,10 +57,23 @@  rte_ring_get_memsize(unsigned count)
 		return -EINVAL;
 	}
 
-	sz = sizeof(struct rte_ring) + count * sizeof(void *);
+	elt_sz = (flags & RING_F_NB) ? 2 * sizeof(void *) : sizeof(void *);
+
+	sz = sizeof(struct rte_ring) + count * elt_sz;
 	sz = RTE_ALIGN(sz, RTE_CACHE_LINE_SIZE);
 	return sz;
 }
+BIND_DEFAULT_SYMBOL(rte_ring_get_memsize, _v1905, 19.05);
+MAP_STATIC_SYMBOL(ssize_t rte_ring_get_memsize(unsigned int count,
+					       unsigned int flags),
+		  rte_ring_get_memsize_v1905);
+
+ssize_t
+rte_ring_get_memsize_v20(unsigned int count)
+{
+	return rte_ring_get_memsize_v1905(count, 0);
+}
+VERSION_SYMBOL(rte_ring_get_memsize, _v20, 2.0);
 
 int
 rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
@@ -82,8 +95,6 @@  rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
 	if (ret < 0 || ret >= (int)sizeof(r->name))
 		return -ENAMETOOLONG;
 	r->flags = flags;
-	r->prod.single = (flags & RING_F_SP_ENQ) ? __IS_SP : __IS_MP;
-	r->cons.single = (flags & RING_F_SC_DEQ) ? __IS_SC : __IS_MC;
 
 	if (flags & RING_F_EXACT_SZ) {
 		r->size = rte_align32pow2(count + 1);
@@ -100,8 +111,30 @@  rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
 		r->mask = count - 1;
 		r->capacity = r->mask;
 	}
-	r->prod.head = r->cons.head = 0;
-	r->prod.tail = r->cons.tail = 0;
+
+	if (flags & RING_F_NB) {
+		uint64_t i;
+
+		r->prod_64.single = (flags & RING_F_SP_ENQ) ? __IS_SP : __IS_MP;
+		r->cons_64.single = (flags & RING_F_SC_DEQ) ? __IS_SC : __IS_MC;
+		r->prod_64.head = r->cons_64.head = 0;
+		r->prod_64.tail = r->cons_64.tail = 0;
+
+		for (i = 0; i < r->size; i++) {
+			struct nb_ring_entry *ring_ptr, *base;
+
+			base = ((struct nb_ring_entry *)&r[1]);
+
+			ring_ptr = &base[i & r->mask];
+
+			ring_ptr->cnt = i;
+		}
+	} else {
+		r->prod.single = (flags & RING_F_SP_ENQ) ? __IS_SP : __IS_MP;
+		r->cons.single = (flags & RING_F_SC_DEQ) ? __IS_SC : __IS_MC;
+		r->prod.head = r->cons.head = 0;
+		r->prod.tail = r->cons.tail = 0;
+	}
 
 	return 0;
 }
@@ -123,11 +156,19 @@  rte_ring_create(const char *name, unsigned count, int socket_id,
 
 	ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);
 
+#if !defined(RTE_ARCH_X86_64)
+	if (flags & RING_F_NB) {
+		printf("RING_F_NB is only supported on x86-64 platforms\n");
+		rte_errno = EINVAL;
+		return NULL;
+	}
+#endif
+
 	/* for an exact size ring, round up from count to a power of two */
 	if (flags & RING_F_EXACT_SZ)
 		count = rte_align32pow2(count + 1);
 
-	ring_size = rte_ring_get_memsize(count);
+	ring_size = rte_ring_get_memsize(count, flags);
 	if (ring_size < 0) {
 		rte_errno = ring_size;
 		return NULL;
@@ -227,10 +268,17 @@  rte_ring_dump(FILE *f, const struct rte_ring *r)
 	fprintf(f, "  flags=%x\n", r->flags);
 	fprintf(f, "  size=%"PRIu32"\n", r->size);
 	fprintf(f, "  capacity=%"PRIu32"\n", r->capacity);
-	fprintf(f, "  ct=%"PRIu32"\n", r->cons.tail);
-	fprintf(f, "  ch=%"PRIu32"\n", r->cons.head);
-	fprintf(f, "  pt=%"PRIu32"\n", r->prod.tail);
-	fprintf(f, "  ph=%"PRIu32"\n", r->prod.head);
+	if (r->flags & RING_F_NB) {
+		fprintf(f, "  ct=%"PRIu64"\n", r->cons_64.tail);
+		fprintf(f, "  ch=%"PRIu64"\n", r->cons_64.head);
+		fprintf(f, "  pt=%"PRIu64"\n", r->prod_64.tail);
+		fprintf(f, "  ph=%"PRIu64"\n", r->prod_64.head);
+	} else {
+		fprintf(f, "  ct=%"PRIu32"\n", r->cons.tail);
+		fprintf(f, "  ch=%"PRIu32"\n", r->cons.head);
+		fprintf(f, "  pt=%"PRIu32"\n", r->prod.tail);
+		fprintf(f, "  ph=%"PRIu32"\n", r->prod.head);
+	}
 	fprintf(f, "  used=%u\n", rte_ring_count(r));
 	fprintf(f, "  avail=%u\n", rte_ring_free_count(r));
 }
diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index 00dfb5b85..c3d388c95 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -20,12 +20,16 @@ 
  *
  * - FIFO (First In First Out)
  * - Maximum size is fixed; the pointers are stored in a table.
- * - Lockless implementation.
+ * - Lockless (and optionally, non-blocking) implementation.
  * - Multi- or single-consumer dequeue.
  * - Multi- or single-producer enqueue.
  * - Bulk dequeue.
  * - Bulk enqueue.
  *
+ * The non-blocking ring algorithm is based on the original rte ring (derived
+ * from FreeBSD's bufring.h) and inspired by Michael and Scott's non-blocking
+ * concurrent queue.
+ *
  * Note: the ring implementation is not preemptible. Refer to Programmer's
  * guide/Environment Abstraction Layer/Multiple pthread/Known Issues/rte_ring
  * for more information.
@@ -134,6 +138,18 @@  struct rte_ring {
  */
 #define RING_F_EXACT_SZ 0x0004
 #define RTE_RING_SZ_MASK  (0x7fffffffU) /**< Ring size mask */
+/**
+ * The ring uses non-blocking enqueue and dequeue functions. These functions
+ * do not have the "non-preemptive" constraint of a regular rte ring, and thus
+ * are suited for applications using preemptible pthreads. However, the
+ * non-blocking functions have worse average-case performance than their
+ * regular rte ring counterparts. When used as the handler for a mempool,
+ * per-thread caching can mitigate the performance difference by reducing the
+ * number (and contention) of ring accesses.
+ *
+ * This flag is only supported on x86_64 platforms.
+ */
+#define RING_F_NB 0x0008
 
 /* @internal defines for passing to the enqueue dequeue worker functions */
 #define __IS_SP 1
@@ -151,11 +167,15 @@  struct rte_ring {
  *
  * @param count
  *   The number of elements in the ring (must be a power of 2).
+ * @param flags
+ *   The flags the ring will be created with.
  * @return
  *   - The memory size needed for the ring on success.
  *   - -EINVAL if count is not a power of 2.
  */
-ssize_t rte_ring_get_memsize(unsigned count);
+ssize_t rte_ring_get_memsize(unsigned int count, unsigned int flags);
+ssize_t rte_ring_get_memsize_v20(unsigned int count);
+ssize_t rte_ring_get_memsize_v1905(unsigned int count, unsigned int flags);
 
 /**
  * Initialize a ring structure.
@@ -188,6 +208,10 @@  ssize_t rte_ring_get_memsize(unsigned count);
  *    - RING_F_SC_DEQ: If this flag is set, the default behavior when
  *      using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
  *      is "single-consumer". Otherwise, it is "multi-consumers".
+ *    - RING_F_EXACT_SZ: If this flag is set, count can be a non-power-of-2
+ *      number, but up to half the ring space may be wasted.
+ *    - RING_F_NB: (x86_64 only) If this flag is set, the ring uses
+ *      non-blocking variants of the dequeue and enqueue functions.
  * @return
  *   0 on success, or a negative value on error.
  */
@@ -223,12 +247,17 @@  int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
  *    - RING_F_SC_DEQ: If this flag is set, the default behavior when
  *      using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
  *      is "single-consumer". Otherwise, it is "multi-consumers".
+ *    - RING_F_EXACT_SZ: If this flag is set, count can be a non-power-of-2
+ *      number, but up to half the ring space may be wasted.
+ *    - RING_F_NB: (x86_64 only) If this flag is set, the ring uses
+ *      non-blocking variants of the dequeue and enqueue functions.
  * @return
  *   On success, the pointer to the new allocated ring. NULL on error with
  *    rte_errno set appropriately. Possible errno values include:
  *    - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
  *    - E_RTE_SECONDARY - function was called from a secondary process instance
- *    - EINVAL - count provided is not a power of 2
+ *    - EINVAL - count provided is not a power of 2, or RING_F_NB is used on an
+ *      unsupported platform
  *    - ENOSPC - the maximum number of memzones has already been allocated
  *    - EEXIST - a memzone with the same name already exists
  *    - ENOMEM - no appropriate memory area found in which to create memzone
@@ -284,6 +313,50 @@  void rte_ring_dump(FILE *f, const struct rte_ring *r);
 	} \
 } while (0)
 
+/* The actual enqueue of pointers on the ring.
+ * Used only by the single-producer non-blocking enqueue function, but
+ * out-lined here for code readability.
+ */
+#define ENQUEUE_PTRS_NB(r, ring_start, prod_head, obj_table, n) do { \
+	unsigned int i; \
+	const uint32_t size = (r)->size; \
+	size_t idx = prod_head & (r)->mask; \
+	size_t new_cnt = prod_head + size; \
+	struct nb_ring_entry *ring = (struct nb_ring_entry *)ring_start; \
+	if (likely(idx + n < size)) { \
+		for (i = 0; i < (n & ((~(unsigned)0x3))); i += 4, idx += 4) { \
+			ring[idx].ptr = obj_table[i]; \
+			ring[idx].cnt = new_cnt + i;  \
+			ring[idx + 1].ptr = obj_table[i + 1]; \
+			ring[idx + 1].cnt = new_cnt + i + 1;  \
+			ring[idx + 2].ptr = obj_table[i + 2]; \
+			ring[idx + 2].cnt = new_cnt + i + 2;  \
+			ring[idx + 3].ptr = obj_table[i + 3]; \
+			ring[idx + 3].cnt = new_cnt + i + 3;  \
+		} \
+		switch (n & 0x3) { \
+		case 3: \
+			ring[idx].cnt = new_cnt + i; \
+			ring[idx++].ptr = obj_table[i++]; /* fallthrough */ \
+		case 2: \
+			ring[idx].cnt = new_cnt + i; \
+			ring[idx++].ptr = obj_table[i++]; /* fallthrough */ \
+		case 1: \
+			ring[idx].cnt = new_cnt + i; \
+			ring[idx++].ptr = obj_table[i++]; \
+		} \
+	} else { \
+		for (i = 0; idx < size; i++, idx++) { \
+			ring[idx].cnt = new_cnt + i;  \
+			ring[idx].ptr = obj_table[i]; \
+		} \
+		for (idx = 0; i < n; i++, idx++) {    \
+			ring[idx].cnt = new_cnt + i;  \
+			ring[idx].ptr = obj_table[i]; \
+		} \
+	} \
+} while (0)
+
 /* the actual copy of pointers on the ring to obj_table.
  * Placed here since identical code needed in both
  * single and multi consumer dequeue functions */
@@ -315,6 +388,45 @@  void rte_ring_dump(FILE *f, const struct rte_ring *r);
 	} \
 } while (0)
 
+/* The actual copy of pointers on the ring to obj_table.
+ * Placed here since identical code needed in both
+ * single and multi consumer non-blocking dequeue functions.
+ */
+#define DEQUEUE_PTRS_NB(r, ring_start, cons_head, obj_table, n) do { \
+	unsigned int i; \
+	size_t idx = cons_head & (r)->mask; \
+	const uint32_t size = (r)->size; \
+	struct nb_ring_entry *ring = (struct nb_ring_entry *)ring_start; \
+	if (likely(idx + n < size)) { \
+		for (i = 0; i < (n & (~(unsigned)0x3)); i += 4, idx += 4) {\
+			obj_table[i] = ring[idx].ptr; \
+			obj_table[i + 1] = ring[idx + 1].ptr; \
+			obj_table[i + 2] = ring[idx + 2].ptr; \
+			obj_table[i + 3] = ring[idx + 3].ptr; \
+		} \
+		switch (n & 0x3) { \
+		case 3: \
+			obj_table[i++] = ring[idx++].ptr; /* fallthrough */ \
+		case 2: \
+			obj_table[i++] = ring[idx++].ptr; /* fallthrough */ \
+		case 1: \
+			obj_table[i++] = ring[idx++].ptr; \
+		} \
+	} else { \
+		for (i = 0; idx < size; i++, idx++) \
+			obj_table[i] = ring[idx].ptr; \
+		for (idx = 0; i < n; i++, idx++) \
+			obj_table[i] = ring[idx].ptr; \
+	} \
+} while (0)
+
+
+/* @internal 128-bit structure used by the non-blocking ring */
+struct nb_ring_entry {
+	void *ptr; /**< Data pointer */
+	uint64_t cnt; /**< Modification counter */
+};
+
 /* Between load and load. there might be cpu reorder in weak model
  * (powerpc/arm).
  * There are 2 choices for the users
@@ -331,6 +443,70 @@  void rte_ring_dump(FILE *f, const struct rte_ring *r);
 #endif
 
 /**
+ * @internal Enqueue several objects on the non-blocking ring
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items to the ring
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible to the ring
+ * @param is_sp
+ *   Indicates whether to use single producer or multi-producer head update
+ * @param free_space
+ *   returns the amount of space after the enqueue operation has finished
+ * @return
+ *   Actual number of objects enqueued.
+ *   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_enqueue(struct rte_ring *r, void * const *obj_table,
+			 unsigned int n, enum rte_ring_queue_behavior behavior,
+			 unsigned int is_sp, unsigned int *free_space)
+{
+	if (is_sp)
+		return __rte_ring_do_nb_enqueue_sp(r, obj_table, n,
+						   behavior, free_space);
+	else
+		return __rte_ring_do_nb_enqueue_mp(r, obj_table, n,
+						   behavior, free_space);
+}
+
+/**
+ * @internal Dequeue several objects from the non-blocking ring
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to pull from the ring.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Dequeue a fixed number of items from the ring
+ *   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from the ring
+ * @param available
+ *   returns the number of remaining ring entries after the dequeue has finished
+ * @return
+ *   - Actual number of objects dequeued.
+ *     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_dequeue(struct rte_ring *r, void **obj_table,
+		 unsigned int n, enum rte_ring_queue_behavior behavior,
+		 unsigned int is_sc, unsigned int *available)
+{
+	if (is_sc)
+		return __rte_ring_do_nb_dequeue_sc(r, obj_table, n,
+						   behavior, available);
+	else
+		return __rte_ring_do_nb_dequeue_mc(r, obj_table, n,
+						   behavior, available);
+}
+
+/**
  * @internal Enqueue several objects on the ring
  *
   * @param r
@@ -437,8 +613,14 @@  static __rte_always_inline unsigned int
 rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
 			 unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
-			__IS_MP, free_space);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_enqueue(r, obj_table, n,
+						RTE_RING_QUEUE_FIXED, __IS_MP,
+						free_space);
+	else
+		return __rte_ring_do_enqueue(r, obj_table, n,
+					     RTE_RING_QUEUE_FIXED, __IS_MP,
+					     free_space);
 }
 
 /**
@@ -460,8 +642,14 @@  static __rte_always_inline unsigned int
 rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
 			 unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
-			__IS_SP, free_space);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_enqueue(r, obj_table, n,
+						RTE_RING_QUEUE_FIXED, __IS_SP,
+						free_space);
+	else
+		return __rte_ring_do_enqueue(r, obj_table, n,
+					     RTE_RING_QUEUE_FIXED, __IS_SP,
+					     free_space);
 }
 
 /**
@@ -487,8 +675,14 @@  static __rte_always_inline unsigned int
 rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
 		      unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
-			r->prod.single, free_space);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_enqueue(r, obj_table, n,
+						RTE_RING_QUEUE_FIXED,
+						r->prod_64.single, free_space);
+	else
+		return __rte_ring_do_enqueue(r, obj_table, n,
+					     RTE_RING_QUEUE_FIXED,
+					     r->prod.single, free_space);
 }
 
 /**
@@ -571,8 +765,14 @@  static __rte_always_inline unsigned int
 rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table,
 		unsigned int n, unsigned int *available)
 {
-	return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
-			__IS_MC, available);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_dequeue(r, obj_table, n,
+						RTE_RING_QUEUE_FIXED, __IS_MC,
+						available);
+	else
+		return __rte_ring_do_dequeue(r, obj_table, n,
+					     RTE_RING_QUEUE_FIXED, __IS_MC,
+					     available);
 }
 
 /**
@@ -595,8 +795,14 @@  static __rte_always_inline unsigned int
 rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table,
 		unsigned int n, unsigned int *available)
 {
-	return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
-			__IS_SC, available);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_dequeue(r, obj_table, n,
+						RTE_RING_QUEUE_FIXED, __IS_SC,
+						available);
+	else
+		return __rte_ring_do_dequeue(r, obj_table, n,
+					     RTE_RING_QUEUE_FIXED, __IS_SC,
+					     available);
 }
 
 /**
@@ -622,8 +828,14 @@  static __rte_always_inline unsigned int
 rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned int n,
 		unsigned int *available)
 {
-	return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
-				r->cons.single, available);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_dequeue(r, obj_table, n,
+						RTE_RING_QUEUE_FIXED,
+						r->cons_64.single, available);
+	else
+		return __rte_ring_do_dequeue(r, obj_table, n,
+					     RTE_RING_QUEUE_FIXED,
+					     r->cons.single, available);
 }
 
 /**
@@ -698,9 +910,13 @@  rte_ring_dequeue(struct rte_ring *r, void **obj_p)
 static inline unsigned
 rte_ring_count(const struct rte_ring *r)
 {
-	uint32_t prod_tail = r->prod.tail;
-	uint32_t cons_tail = r->cons.tail;
-	uint32_t count = (prod_tail - cons_tail) & r->mask;
+	uint32_t count;
+
+	if (r->flags & RING_F_NB)
+		count = (r->prod_64.tail - r->cons_64.tail) & r->mask;
+	else
+		count = (r->prod.tail - r->cons.tail) & r->mask;
+
 	return (count > r->capacity) ? r->capacity : count;
 }
 
@@ -820,8 +1036,14 @@  static __rte_always_inline unsigned
 rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
 			 unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_do_enqueue(r, obj_table, n,
-			RTE_RING_QUEUE_VARIABLE, __IS_MP, free_space);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_enqueue(r, obj_table, n,
+						RTE_RING_QUEUE_VARIABLE,
+						__IS_MP, free_space);
+	else
+		return __rte_ring_do_enqueue(r, obj_table, n,
+					     RTE_RING_QUEUE_VARIABLE,
+					     __IS_MP, free_space);
 }
 
 /**
@@ -843,8 +1065,14 @@  static __rte_always_inline unsigned
 rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
 			 unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_do_enqueue(r, obj_table, n,
-			RTE_RING_QUEUE_VARIABLE, __IS_SP, free_space);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_enqueue(r, obj_table, n,
+						RTE_RING_QUEUE_VARIABLE,
+						__IS_SP, free_space);
+	else
+		return __rte_ring_do_enqueue(r, obj_table, n,
+					     RTE_RING_QUEUE_VARIABLE,
+					     __IS_SP, free_space);
 }
 
 /**
@@ -870,8 +1098,14 @@  static __rte_always_inline unsigned
 rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
 		      unsigned int n, unsigned int *free_space)
 {
-	return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE,
-			r->prod.single, free_space);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_enqueue(r, obj_table, n,
+						RTE_RING_QUEUE_VARIABLE,
+						r->prod_64.single, free_space);
+	else
+		return __rte_ring_do_enqueue(r, obj_table, n,
+					     RTE_RING_QUEUE_VARIABLE,
+					     r->prod.single, free_space);
 }
 
 /**
@@ -898,8 +1132,14 @@  static __rte_always_inline unsigned
 rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table,
 		unsigned int n, unsigned int *available)
 {
-	return __rte_ring_do_dequeue(r, obj_table, n,
-			RTE_RING_QUEUE_VARIABLE, __IS_MC, available);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_dequeue(r, obj_table, n,
+						RTE_RING_QUEUE_VARIABLE,
+						__IS_MC, available);
+	else
+		return __rte_ring_do_dequeue(r, obj_table, n,
+					     RTE_RING_QUEUE_VARIABLE,
+					     __IS_MC, available);
 }
 
 /**
@@ -923,8 +1163,14 @@  static __rte_always_inline unsigned
 rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table,
 		unsigned int n, unsigned int *available)
 {
-	return __rte_ring_do_dequeue(r, obj_table, n,
-			RTE_RING_QUEUE_VARIABLE, __IS_SC, available);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_dequeue(r, obj_table, n,
+						RTE_RING_QUEUE_VARIABLE,
+						__IS_SC, available);
+	else
+		return __rte_ring_do_dequeue(r, obj_table, n,
+					     RTE_RING_QUEUE_VARIABLE,
+					     __IS_SC, available);
 }
 
 /**
@@ -950,9 +1196,14 @@  static __rte_always_inline unsigned
 rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table,
 		unsigned int n, unsigned int *available)
 {
-	return __rte_ring_do_dequeue(r, obj_table, n,
-				RTE_RING_QUEUE_VARIABLE,
-				r->cons.single, available);
+	if (r->flags & RING_F_NB)
+		return __rte_ring_do_nb_dequeue(r, obj_table, n,
+						RTE_RING_QUEUE_VARIABLE,
+						r->cons_64.single, available);
+	else
+		return __rte_ring_do_dequeue(r, obj_table, n,
+					     RTE_RING_QUEUE_VARIABLE,
+					     r->cons.single, available);
 }
 
 #ifdef __cplusplus
diff --git a/lib/librte_ring/rte_ring_c11_mem.h b/lib/librte_ring/rte_ring_c11_mem.h
index 47acd4c7c..7f83a5dc9 100644
--- a/lib/librte_ring/rte_ring_c11_mem.h
+++ b/lib/librte_ring/rte_ring_c11_mem.h
@@ -221,8 +221,8 @@  __rte_ring_move_prod_head_64(struct rte_ring *r, unsigned int is_sp,
 		/* Ensure the head is read before tail */
 		__atomic_thread_fence(__ATOMIC_ACQUIRE);
 
-		/* load-acquire synchronize with store-release of ht->tail
-		 * in update_tail.
+		/* load-acquire synchronize with store-release of tail in
+		 * do_nb_dequeue_{sc, mc}.
 		 */
 		cons_tail = __atomic_load_n(&r->cons_64.tail,
 					__ATOMIC_ACQUIRE);
@@ -252,6 +252,7 @@  __rte_ring_move_prod_head_64(struct rte_ring *r, unsigned int is_sp,
 					0, __ATOMIC_RELAXED,
 					__ATOMIC_RELAXED);
 	} while (unlikely(success == 0));
+
 	return n;
 }
 
@@ -298,8 +299,8 @@  __rte_ring_move_cons_head_64(struct rte_ring *r, unsigned int is_sc,
 		/* Ensure the head is read before tail */
 		__atomic_thread_fence(__ATOMIC_ACQUIRE);
 
-		/* this load-acquire synchronize with store-release of ht->tail
-		 * in update_tail.
+		/* load-acquire synchronize with store-release of tail in
+		 * do_nb_enqueue_{sp, mp}.
 		 */
 		prod_tail = __atomic_load_n(&r->prod_64.tail,
 					__ATOMIC_ACQUIRE);
@@ -328,6 +329,279 @@  __rte_ring_move_cons_head_64(struct rte_ring *r, unsigned int is_sc,
 							0, __ATOMIC_RELAXED,
 							__ATOMIC_RELAXED);
 	} while (unlikely(success == 0));
+
+	return n;
+}
+
+/**
+ * @internal
+ *   Enqueue several objects on the non-blocking ring (single-producer only)
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items to the ring
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible to the ring
+ * @param free_space
+ *   returns the amount of space after the enqueue operation has finished
+ * @return
+ *   Actual number of objects enqueued.
+ *   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_enqueue_sp(struct rte_ring *r, void * const *obj_table,
+			    unsigned int n,
+			    enum rte_ring_queue_behavior behavior,
+			    unsigned int *free_space)
+{
+	uint32_t free_entries;
+	uint64_t head, next;
+
+	n = __rte_ring_move_prod_head_64(r, 1, n, behavior,
+					 &head, &next, &free_entries);
+	if (n == 0)
+		goto end;
+
+	ENQUEUE_PTRS_NB(r, &r[1], head, obj_table, n);
+
+	__atomic_store_n(&r->prod_64.tail,
+			 r->prod_64.tail + n,
+			 __ATOMIC_RELEASE);
+end:
+	if (free_space != NULL)
+		*free_space = free_entries - n;
+	return n;
+}
+
+/**
+ * @internal
+ *   Enqueue several objects on the non-blocking ring (multi-producer safe)
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items to the ring
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible to the ring
+ * @param free_space
+ *   returns the amount of space after the enqueue operation has finished
+ * @return
+ *   Actual number of objects enqueued.
+ *   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_enqueue_mp(struct rte_ring *r, void * const *obj_table,
+			    unsigned int n,
+			    enum rte_ring_queue_behavior behavior,
+			    unsigned int *free_space)
+{
+#if !defined(RTE_ARCH_X86_64) || !defined(ALLOW_EXPERIMENTAL_API)
+	RTE_SET_USED(r);
+	RTE_SET_USED(obj_table);
+	RTE_SET_USED(n);
+	RTE_SET_USED(behavior);
+	RTE_SET_USED(free_space);
+#ifndef ALLOW_EXPERIMENTAL_API
+	printf("[%s()] RING_F_NB requires an experimental API."
+	       " Recompile with ALLOW_EXPERIMENTAL_API to use it.\n"
+	       , __func__);
+#endif
+	return 0;
+#endif
+#if defined(RTE_ARCH_X86_64) && defined(ALLOW_EXPERIMENTAL_API)
+	uint64_t head, next, tail;
+	uint32_t free_entries;
+	unsigned int i;
+
+	n = __rte_ring_move_prod_head_64(r, 0, n, behavior,
+					 &head, &next, &free_entries);
+	if (n == 0)
+		goto end;
+
+	tail = __atomic_load_n(&r->prod_64.tail, __ATOMIC_RELAXED);
+
+	for (i = 0; i < n; /* i incremented if enqueue succeeds */) {
+		struct nb_ring_entry old_value, new_value;
+		struct nb_ring_entry *base, *ring_ptr;
+
+		/* Enqueue to the tail entry. If another thread wins the race,
+		 * retry with the new tail.
+		 */
+		base = (struct nb_ring_entry *)&r[1];
+
+		ring_ptr = &base[tail & r->mask];
+
+		old_value = *ring_ptr;
+
+		/* If the tail entry's modification counter doesn't match the
+		 * producer tail index, it's already been updated.
+		 *
+		 * Attempt to update the tail here, so this thread doesn't
+		 * depend on the forward progress of the thread that
+		 * successfully enqueued.
+		 */
+		if (old_value.cnt != tail) {
+			/* Use a release memmodel to ensure the tail entry is
+			 * visible to dequeueing threads before updating the
+			 * tail. (tail is updated on failure.)
+			 */
+			__atomic_compare_exchange_n(&r->prod_64.tail,
+						    &tail, tail + 1,
+						    0, __ATOMIC_RELEASE,
+						    __ATOMIC_RELAXED);
+			continue;
+		}
+
+		/* Prepare the new entry. The cnt field mitigates the ABA
+		 * problem on the ring write.
+		 */
+		new_value.ptr = obj_table[i];
+		new_value.cnt = tail + r->size;
+
+		if (rte_atomic128_cmpset((volatile rte_int128_t *)ring_ptr,
+					 (rte_int128_t *)&old_value,
+					 (rte_int128_t *)&new_value,
+					 0, RTE_ATOMIC_RELAXED,
+					 RTE_ATOMIC_RELAXED))
+			i++;
+
+		/* Use a release memmodel to ensure the tail entry is visible
+		 * to dequeueing threads before updating the tail. Every thread
+		 * attempts the cmpset, so they don't have to wait for the
+		 * thread that successfully enqueued to the ring. Using a
+		 * 64-bit tail mitigates the ABA problem here. (tail is updated
+		 * on failure.)
+		 */
+		__atomic_compare_exchange_n(&r->prod_64.tail,
+					    &tail, tail + 1,
+					    0, __ATOMIC_RELEASE,
+					    __ATOMIC_RELAXED);
+	}
+
+end:
+	if (free_space != NULL)
+		*free_space = free_entries - n;
+	return n;
+#endif
+}
+
+/**
+ * @internal
+ *   Dequeue several objects from the non-blocking ring (single-consumer only)
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to pull from the ring.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Dequeue a fixed number of items from the ring
+ *   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from the ring
+ * @param available
+ *   returns the number of remaining ring entries after the dequeue has finished
+ * @return
+ *   - Actual number of objects dequeued.
+ *     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_dequeue_sc(struct rte_ring *r, void **obj_table,
+			    unsigned int n,
+			    enum rte_ring_queue_behavior behavior,
+			    unsigned int *available)
+{
+	uint64_t head, next;
+	uint32_t entries;
+
+	n = __rte_ring_move_cons_head_64(r, 1, n, behavior,
+					 &head, &next, &entries);
+	if (n == 0)
+		goto end;
+
+	DEQUEUE_PTRS_NB(r, &r[1], head, obj_table, n);
+
+	__atomic_store_n(&r->cons_64.tail,
+			 r->cons_64.tail + n,
+			 __ATOMIC_RELEASE);
+end:
+	if (available != NULL)
+		*available = entries - n;
+	return n;
+}
+
+/**
+ * @internal
+ *   Dequeue several objects from the non-blocking ring (multi-consumer safe)
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to pull from the ring.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Dequeue a fixed number of items from the ring
+ *   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from the ring
+ * @param available
+ *   returns the number of remaining ring entries after the dequeue has finished
+ * @return
+ *   - Actual number of objects dequeued.
+ *     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_dequeue_mc(struct rte_ring *r, void **obj_table,
+			    unsigned int n,
+			    enum rte_ring_queue_behavior behavior,
+			    unsigned int *available)
+{
+	uint64_t head, tail, next;
+	uint32_t entries;
+	int success;
+
+	n = __rte_ring_move_cons_head_64(r, 0, n, behavior,
+					 &head, &next, &entries);
+	if (n == 0)
+		goto end;
+
+	/* The acquire-release synchronization on prod_64.tail ensures that
+	 * this thread correctly observes the ring entries up to prod_64.tail.
+	 * However by the time this thread reads cons_64.tail, or if its CAS
+	 * fails, cons_64.tail may have passed the previously read value of
+	 * prod_64.tail. Acquire-release synchronization on cons_64.tail is
+	 * necessary to ensure that dequeue threads always observe the correct
+	 * values of the ring entries.
+	 */
+	tail = __atomic_load_n(&r->cons_64.tail, __ATOMIC_ACQUIRE);
+	do {
+		/* Dequeue from the cons tail onwards. If multiple threads read
+		 * the same pointers, the thread that successfully performs the
+		 * CAS will keep them and the other(s) will retry.
+		 */
+		DEQUEUE_PTRS_NB(r, &r[1], tail, obj_table, n);
+
+		next = tail + n;
+
+		/* There is potential for the ABA problem here, but that is
+		 * mitigated by the large (64-bit) tail. Use a release memmodel
+		 * to ensure the dequeue operations and CAS are properly
+		 * ordered. (tail is updated on failure.)
+		 */
+		success = __atomic_compare_exchange_n(&r->cons_64.tail,
+						      &tail, next,
+						      0, __ATOMIC_RELEASE,
+						      __ATOMIC_ACQUIRE);
+	} while (success == 0);
+
+end:
+	if (available != NULL)
+		*available = entries - n;
 	return n;
 }
 
diff --git a/lib/librte_ring/rte_ring_generic.h b/lib/librte_ring/rte_ring_generic.h
index 2158e092a..87c9a09ce 100644
--- a/lib/librte_ring/rte_ring_generic.h
+++ b/lib/librte_ring/rte_ring_generic.h
@@ -306,4 +306,273 @@  __rte_ring_move_cons_head_64(struct rte_ring *r, unsigned int is_sc,
 	return n;
 }
 
+/**
+ * @internal
+ *   Enqueue several objects on the non-blocking ring (single-producer only)
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items to the ring
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible to the ring
+ * @param free_space
+ *   returns the amount of space after the enqueue operation has finished
+ * @return
+ *   Actual number of objects enqueued.
+ *   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_enqueue_sp(struct rte_ring *r, void * const *obj_table,
+			    unsigned int n,
+			    enum rte_ring_queue_behavior behavior,
+			    unsigned int *free_space)
+{
+	uint32_t free_entries;
+	uint64_t head, next;
+
+	n = __rte_ring_move_prod_head_64(r, 1, n, behavior,
+					 &head, &next, &free_entries);
+	if (n == 0)
+		goto end;
+
+	ENQUEUE_PTRS_NB(r, &r[1], head, obj_table, n);
+
+	rte_smp_wmb();
+
+	r->prod_64.tail += n;
+
+end:
+	if (free_space != NULL)
+		*free_space = free_entries - n;
+	return n;
+}
+
+/**
+ * @internal
+ *   Enqueue several objects on the non-blocking ring (multi-producer safe)
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items to the ring
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible to the ring
+ * @param free_space
+ *   returns the amount of space after the enqueue operation has finished
+ * @return
+ *   Actual number of objects enqueued.
+ *   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_enqueue_mp(struct rte_ring *r, void * const *obj_table,
+			    unsigned int n,
+			    enum rte_ring_queue_behavior behavior,
+			    unsigned int *free_space)
+{
+#if !defined(RTE_ARCH_X86_64) || !defined(ALLOW_EXPERIMENTAL_API)
+	RTE_SET_USED(r);
+	RTE_SET_USED(obj_table);
+	RTE_SET_USED(n);
+	RTE_SET_USED(behavior);
+	RTE_SET_USED(free_space);
+#ifndef ALLOW_EXPERIMENTAL_API
+	printf("[%s()] RING_F_NB requires an experimental API."
+	       " Recompile with ALLOW_EXPERIMENTAL_API to use it.\n"
+	       , __func__);
+#endif
+	return 0;
+#endif
+#if defined(RTE_ARCH_X86_64) && defined(ALLOW_EXPERIMENTAL_API)
+	uint64_t head, next, tail;
+	uint32_t free_entries;
+	unsigned int i;
+
+	n = __rte_ring_move_prod_head_64(r, 0, n, behavior,
+					 &head, &next, &free_entries);
+	if (n == 0)
+		goto end;
+
+	for (i = 0; i < n; /* i incremented if enqueue succeeds */) {
+		struct nb_ring_entry old_value, new_value;
+		struct nb_ring_entry *base, *ring_ptr;
+
+		/* Enqueue to the tail entry. If another thread wins the race,
+		 * retry with the new tail.
+		 */
+		tail = r->prod_64.tail;
+
+		base = (struct nb_ring_entry *)&r[1];
+
+		ring_ptr = &base[tail & r->mask];
+
+		old_value = *ring_ptr;
+
+		/* If the tail entry's modification counter doesn't match the
+		 * producer tail index, it's already been updated.
+		 *
+		 * Attempt to update the tail here, so this thread doesn't
+		 * depend on the forward progress of the thread that
+		 * successfully enqueued.
+		 */
+		if (old_value.cnt != tail) {
+			/* Ensure the tail entry is visible to dequeueing
+			 * threads before updating the tail.
+			 */
+			rte_smp_wmb();
+
+			rte_atomic64_cmpset(&r->prod_64.tail, tail, tail + 1);
+			continue;
+		}
+
+		/* Prepare the new entry. The cnt field mitigates the ABA
+		 * problem on the ring write.
+		 */
+		new_value.ptr = obj_table[i];
+		new_value.cnt = tail + r->size;
+
+		if (rte_atomic128_cmpset((volatile rte_int128_t *)ring_ptr,
+					 (rte_int128_t *)&old_value,
+					 (rte_int128_t *)&new_value,
+					 0, RTE_ATOMIC_RELAXED,
+					 RTE_ATOMIC_RELAXED))
+			i++;
+
+		/* Ensure the tail entry is visible to dequeueing threads
+		 * before updating the tail.
+		 */
+		rte_smp_wmb();
+
+		/* Every thread attempts the cmpset, so they don't have to wait
+		 * for the thread that successfully enqueued to the ring.
+		 * Using a 64-bit tail mitigates the ABA problem here.
+		 */
+		rte_atomic64_cmpset(&r->prod_64.tail, tail, tail + 1);
+	}
+
+end:
+	if (free_space != NULL)
+		*free_space = free_entries - n;
+	return n;
+#endif
+}
+
+/**
+ * @internal
+ *   Dequeue several objects from the non-blocking ring (single-consumer only)
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to pull from the ring.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Dequeue a fixed number of items from the ring
+ *   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from the ring
+ * @param available
+ *   returns the number of remaining ring entries after the dequeue has finished
+ * @return
+ *   - Actual number of objects dequeued.
+ *     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_dequeue_sc(struct rte_ring *r, void **obj_table,
+			    unsigned int n,
+			    enum rte_ring_queue_behavior behavior,
+			    unsigned int *available)
+{
+	uint64_t head, next;
+	uint32_t entries;
+
+	n = __rte_ring_move_cons_head_64(r, 1, n, behavior,
+					 &head, &next, &entries);
+	if (n == 0)
+		goto end;
+
+	DEQUEUE_PTRS_NB(r, &r[1], head, obj_table, n);
+
+	rte_smp_rmb();
+
+	r->cons_64.tail += n;
+
+end:
+	if (available != NULL)
+		*available = entries - n;
+	return n;
+}
+
+/**
+ * @internal
+ *   Dequeue several objects from the non-blocking ring (multi-consumer safe)
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param n
+ *   The number of objects to pull from the ring.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Dequeue a fixed number of items from the ring
+ *   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from the ring
+ * @param available
+ *   returns the number of remaining ring entries after the dequeue has finished
+ * @return
+ *   - Actual number of objects dequeued.
+ *     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_nb_dequeue_mc(struct rte_ring *r, void **obj_table,
+			    unsigned int n,
+			    enum rte_ring_queue_behavior behavior,
+			    unsigned int *available)
+{
+	uint64_t head, next;
+	uint32_t entries;
+	int success;
+
+	n = __rte_ring_move_cons_head_64(r, 0, n, behavior,
+					 &head, &next, &entries);
+	if (n == 0)
+		goto end;
+
+	do {
+		uint64_t tail = r->cons_64.tail;
+
+		/* Ensure that the correct ring entry values are read by this
+		 * thread.
+		 */
+		rte_smp_rmb();
+
+		/* Dequeue from the cons tail onwards. If multiple threads read
+		 * the same pointers, the thread that successfully performs the
+		 * CAS will keep them and the other(s) will retry.
+		 */
+		DEQUEUE_PTRS_NB(r, &r[1], tail, obj_table, n);
+
+		next = tail + n;
+
+		/* Ensure the dequeue operations and CAS are properly
+		 * ordered.
+		 */
+		rte_smp_rmb();
+
+		/* There is potential for the ABA problem here, but that is
+		 * mitigated by the large (64-bit) tail.
+		 */
+		success = rte_atomic64_cmpset(&r->cons_64.tail, tail, next);
+	} while (success == 0);
+
+end:
+	if (available != NULL)
+		*available = entries - n;
+	return n;
+}
+
 #endif /* _RTE_RING_GENERIC_H_ */
diff --git a/lib/librte_ring/rte_ring_version.map b/lib/librte_ring/rte_ring_version.map
index d935efd0d..8969467af 100644
--- a/lib/librte_ring/rte_ring_version.map
+++ b/lib/librte_ring/rte_ring_version.map
@@ -17,3 +17,10 @@  DPDK_2.2 {
 	rte_ring_free;
 
 } DPDK_2.0;
+
+DPDK_19.05 {
+	global:
+
+	rte_ring_get_memsize;
+
+} DPDK_2.2;