[dpdk-dev] [PATCH 16/22] event/dlb2: add dequeue and its burst variants

[Timothy McDaniel <timothy.mcdaniel@intel.com>]

Add support for dequeue, dequeue_burst, ...

Signed-off-by: Timothy McDaniel <timothy.mcdaniel@intel.com>
---
 drivers/event/dlb2/dlb2.c | 786 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 786 insertions(+)

diff --git a/drivers/event/dlb2/dlb2.c b/drivers/event/dlb2/dlb2.c
index ac4cf19..8911c55 100644
--- a/drivers/event/dlb2/dlb2.c
+++ b/drivers/event/dlb2/dlb2.c
@@ -2751,9 +2751,786 @@ dlb2_event_enqueue_forward_burst(void *event_port,
 	return dlb2_event_enqueue_burst(event_port, events, num);
 }
 
+static inline void
+dlb2_port_credits_inc(struct dlb2_port *qm_port, int num)
+{
+	uint32_t batch_size = DLB2_SW_CREDIT_BATCH_SZ;
+
+	/* increment port credits, and return to pool if exceeds threshold */
+	if (!qm_port->is_directed) {
+		qm_port->cached_ldb_credits += num;
+		if (qm_port->cached_ldb_credits >= 2 * batch_size) {
+			__atomic_fetch_add(
+				qm_port->credit_pool[DLB2_LDB_QUEUE],
+				batch_size, __ATOMIC_SEQ_CST);
+			qm_port->cached_ldb_credits -= batch_size;
+		}
+	} else {
+		qm_port->cached_dir_credits += num;
+		if (qm_port->cached_dir_credits >= 2 * batch_size) {
+			__atomic_fetch_add(
+				qm_port->credit_pool[DLB2_DIR_QUEUE],
+				batch_size, __ATOMIC_SEQ_CST);
+			qm_port->cached_dir_credits -= batch_size;
+		}
+	}
+}
+
+static inline bool
+dlb2_cq_is_empty(struct dlb2_port *qm_port)
+{
+	volatile struct dlb2_dequeue_qe *qe_ptr;
+	struct dlb2_dequeue_qe qe;
+
+	qe_ptr = dlb2_port[qm_port->id][PORT_TYPE(qm_port)].cq_base;
+	qe = qe_ptr[qm_port->cq_idx];
+
+	return (qe.cq_gen != qm_port->gen_bit);
+}
+
+static inline int
+dlb2_dequeue_wait(struct dlb2_eventdev *dlb2,
+		  struct dlb2_eventdev_port *ev_port,
+		  struct dlb2_port *qm_port,
+		  uint64_t timeout,
+		  uint64_t start_ticks)
+{
+	struct process_local_port_data *port_data;
+	uint64_t elapsed_ticks;
+
+	port_data = &dlb2_port[qm_port->id][PORT_TYPE(qm_port)];
+
+	elapsed_ticks = rte_get_timer_cycles() - start_ticks;
+
+	/* Wait/poll time expired */
+	if (elapsed_ticks >= timeout) {
+		return 1;
+	} else if (dlb2->umwait_allowed) {
+		volatile struct dlb2_dequeue_qe *cq_base;
+
+		cq_base = port_data->cq_base;
+
+		/* Block on cache line write to CQ. Note: it's
+		 * safe to access the per-process cq_base
+		 * address here, since the PMD has already
+		 * attempted at least one CQ dequeue.
+		 */
+		dlb2_umonitor(&cq_base[qm_port->cq_idx]);
+
+		/* Avoid race condition. Check if still empty */
+		if (dlb2_cq_is_empty(qm_port)) {
+			dlb2_umwait(RTE_LIBRTE_PMD_DLB2_UMWAIT_CTL_STATE,
+				    timeout + start_ticks);
+			DLB2_INC_STAT(
+				ev_port->stats.traffic.rx_umonitor_umwait, 1);
+		}
+	} else {
+		uint64_t poll_interval = RTE_LIBRTE_PMD_DLB2_POLL_INTERVAL;
+		uint64_t curr_ticks = rte_get_timer_cycles();
+		uint64_t init_ticks = curr_ticks;
+
+		while ((curr_ticks - start_ticks < timeout) &&
+		       (curr_ticks - init_ticks < poll_interval))
+			curr_ticks = rte_get_timer_cycles();
+	}
+
+	return 0;
+}
+
+static inline int
+dlb2_process_dequeue_qes(struct dlb2_eventdev_port *ev_port,
+			 struct dlb2_port *qm_port,
+			 struct rte_event *events,
+			 struct dlb2_dequeue_qe *qes,
+			 int cnt)
+{
+	uint8_t *qid_mappings = qm_port->qid_mappings;
+	int i, num, evq_id;
+
+	RTE_SET_USED(ev_port);  /* avoids unused variable error if stats off */
+
+	for (i = 0, num = 0; i < cnt; i++) {
+		struct dlb2_dequeue_qe *qe = &qes[i];
+		int sched_type_map[DLB2_NUM_HW_SCHED_TYPES] = {
+			[DLB2_SCHED_ATOMIC] = RTE_SCHED_TYPE_ATOMIC,
+			[DLB2_SCHED_UNORDERED] = RTE_SCHED_TYPE_PARALLEL,
+			[DLB2_SCHED_ORDERED] = RTE_SCHED_TYPE_ORDERED,
+			[DLB2_SCHED_DIRECTED] = RTE_SCHED_TYPE_ATOMIC,
+		};
+
+		/* Fill in event information.
+		 * Note that flow_id must be embedded in the data by
+		 * the app, such as the mbuf RSS hash field if the data
+		 * buffer is a mbuf.
+		 */
+		if (unlikely(qe->error)) {
+			DLB2_LOG_ERR("QE error bit ON\n");
+			DLB2_INC_STAT(ev_port->stats.traffic.rx_drop, 1);
+			dlb2_consume_qe_immediate(qm_port, 1);
+			continue; /* Ignore */
+		}
+
+		events[num].u64 = qe->data;
+		events[num].flow_id = qe->flow_id;
+		events[num].priority = DLB2_TO_EV_PRIO((uint8_t)qe->priority);
+		events[num].event_type = qe->u.event_type.major;
+		events[num].sub_event_type = qe->u.event_type.sub;
+		events[num].sched_type = sched_type_map[qe->sched_type];
+		events[num].impl_opaque = qe->qid_depth;
+
+		/* qid not preserved for directed queues */
+		if (qm_port->is_directed)
+			evq_id = ev_port->link[0].queue_id;
+		else
+			evq_id = qid_mappings[qe->qid];
+
+		events[num].queue_id = evq_id;
+		DLB2_INC_STAT(
+			ev_port->stats.queue[evq_id].qid_depth[qe->qid_depth],
+			1);
+		DLB2_INC_STAT(ev_port->stats.rx_sched_cnt[qe->sched_type], 1);
+		DLB2_INC_STAT(ev_port->stats.traffic.rx_ok, 1);
+		num++;
+	}
+
+	return num;
+}
+
+static inline int
+dlb2_process_dequeue_four_qes(struct dlb2_eventdev_port *ev_port,
+			      struct dlb2_port *qm_port,
+			      struct rte_event *events,
+			      struct dlb2_dequeue_qe *qes)
+{
+	int sched_type_map[] = {
+		[DLB2_SCHED_ATOMIC] = RTE_SCHED_TYPE_ATOMIC,
+		[DLB2_SCHED_UNORDERED] = RTE_SCHED_TYPE_PARALLEL,
+		[DLB2_SCHED_ORDERED] = RTE_SCHED_TYPE_ORDERED,
+		[DLB2_SCHED_DIRECTED] = RTE_SCHED_TYPE_ATOMIC,
+	};
+	const int num_events = DLB2_NUM_QES_PER_CACHE_LINE;
+	uint8_t *qid_mappings = qm_port->qid_mappings;
+	__m128i sse_evt[2];
+
+	RTE_SET_USED(ev_port);  /* avoids unused variable error, if stats off */
+
+	/* In the unlikely case that any of the QE error bits are set, process
+	 * them one at a time.
+	 */
+	if (unlikely(qes[0].error || qes[1].error ||
+		     qes[2].error || qes[3].error))
+		return dlb2_process_dequeue_qes(ev_port, qm_port, events,
+						 qes, num_events);
+
+	events[0].u64 = qes[0].data;
+	events[1].u64 = qes[1].data;
+	events[2].u64 = qes[2].data;
+	events[3].u64 = qes[3].data;
+
+	/* Construct the metadata portion of two struct rte_events
+	 * in one 128b SSE register. Event metadata is constructed in the SSE
+	 * registers like so:
+	 * sse_evt[0][63:0]:   event[0]'s metadata
+	 * sse_evt[0][127:64]: event[1]'s metadata
+	 * sse_evt[1][63:0]:   event[2]'s metadata
+	 * sse_evt[1][127:64]: event[3]'s metadata
+	 */
+	sse_evt[0] = _mm_setzero_si128();
+	sse_evt[1] = _mm_setzero_si128();
+
+	/* Convert the hardware queue ID to an event queue ID and store it in
+	 * the metadata:
+	 * sse_evt[0][47:40]   = qid_mappings[qes[0].qid]
+	 * sse_evt[0][111:104] = qid_mappings[qes[1].qid]
+	 * sse_evt[1][47:40]   = qid_mappings[qes[2].qid]
+	 * sse_evt[1][111:104] = qid_mappings[qes[3].qid]
+	 */
+#define RTE_EVENT_QUEUE_ID_BYTE 5
+	sse_evt[0] = _mm_insert_epi8(sse_evt[0],
+				     qid_mappings[qes[0].qid],
+				     RTE_EVENT_QUEUE_ID_BYTE);
+	sse_evt[0] = _mm_insert_epi8(sse_evt[0],
+				     qid_mappings[qes[1].qid],
+				     RTE_EVENT_QUEUE_ID_BYTE + 8);
+	sse_evt[1] = _mm_insert_epi8(sse_evt[1],
+				     qid_mappings[qes[2].qid],
+				     RTE_EVENT_QUEUE_ID_BYTE);
+	sse_evt[1] = _mm_insert_epi8(sse_evt[1],
+				     qid_mappings[qes[3].qid],
+				     RTE_EVENT_QUEUE_ID_BYTE + 8);
+
+	/* Convert the hardware priority to an event priority and store it in
+	 * the metadata, while also returning the queue depth status
+	 * value captured by the hardware, storing it in impl_opaque, which can
+	 * be read by the application but not modified
+	 * sse_evt[0][55:48]   = DLB2_TO_EV_PRIO(qes[0].priority)
+	 * sse_evt[0][63:56]   = qes[0].qid_depth
+	 * sse_evt[0][119:112] = DLB2_TO_EV_PRIO(qes[1].priority)
+	 * sse_evt[0][127:120] = qes[1].qid_depth
+	 * sse_evt[1][55:48]   = DLB2_TO_EV_PRIO(qes[2].priority)
+	 * sse_evt[1][63:56]   = qes[2].qid_depth
+	 * sse_evt[1][119:112] = DLB2_TO_EV_PRIO(qes[3].priority)
+	 * sse_evt[1][127:120] = qes[3].qid_depth
+	 */
+#define RTE_EVENT_PRIO_IMPL_OPAQUE_WORD 3
+#define RTE_BYTE_SHIFT 8
+	sse_evt[0] =
+		_mm_insert_epi16(sse_evt[0],
+			DLB2_TO_EV_PRIO((uint8_t)qes[0].priority) |
+			(qes[0].qid_depth << RTE_BYTE_SHIFT),
+			RTE_EVENT_PRIO_IMPL_OPAQUE_WORD);
+	sse_evt[0] =
+		_mm_insert_epi16(sse_evt[0],
+			DLB2_TO_EV_PRIO((uint8_t)qes[1].priority) |
+			(qes[1].qid_depth << RTE_BYTE_SHIFT),
+			RTE_EVENT_PRIO_IMPL_OPAQUE_WORD + 4);
+	sse_evt[1] =
+		_mm_insert_epi16(sse_evt[1],
+			DLB2_TO_EV_PRIO((uint8_t)qes[2].priority) |
+			(qes[2].qid_depth << RTE_BYTE_SHIFT),
+			RTE_EVENT_PRIO_IMPL_OPAQUE_WORD);
+	sse_evt[1] =
+		_mm_insert_epi16(sse_evt[1],
+			DLB2_TO_EV_PRIO((uint8_t)qes[3].priority) |
+			(qes[3].qid_depth << RTE_BYTE_SHIFT),
+			RTE_EVENT_PRIO_IMPL_OPAQUE_WORD + 4);
+
+	/* Write the event type, sub event type, and flow_id to the event
+	 * metadata.
+	 * sse_evt[0][31:0]   = qes[0].flow_id |
+	 *			qes[0].u.event_type.major << 28 |
+	 *			qes[0].u.event_type.sub << 20;
+	 * sse_evt[0][95:64]  = qes[1].flow_id |
+	 *			qes[1].u.event_type.major << 28 |
+	 *			qes[1].u.event_type.sub << 20;
+	 * sse_evt[1][31:0]   = qes[2].flow_id |
+	 *			qes[2].u.event_type.major << 28 |
+	 *			qes[2].u.event_type.sub << 20;
+	 * sse_evt[1][95:64]  = qes[3].flow_id |
+	 *			qes[3].u.event_type.major << 28 |
+	 *			qes[3].u.event_type.sub << 20;
+	 */
+#define RTE_EVENT_EV_TYPE_DW 0
+#define RTE_EVENT_EV_TYPE_SHIFT 28
+#define RTE_EVENT_SUB_EV_TYPE_SHIFT 20
+	sse_evt[0] = _mm_insert_epi32(sse_evt[0],
+			qes[0].flow_id |
+			qes[0].u.event_type.major << RTE_EVENT_EV_TYPE_SHIFT |
+			qes[0].u.event_type.sub <<  RTE_EVENT_SUB_EV_TYPE_SHIFT,
+			RTE_EVENT_EV_TYPE_DW);
+	sse_evt[0] = _mm_insert_epi32(sse_evt[0],
+			qes[1].flow_id |
+			qes[1].u.event_type.major << RTE_EVENT_EV_TYPE_SHIFT |
+			qes[1].u.event_type.sub <<  RTE_EVENT_SUB_EV_TYPE_SHIFT,
+			RTE_EVENT_EV_TYPE_DW + 2);
+	sse_evt[1] = _mm_insert_epi32(sse_evt[1],
+			qes[2].flow_id |
+			qes[2].u.event_type.major << RTE_EVENT_EV_TYPE_SHIFT |
+			qes[2].u.event_type.sub <<  RTE_EVENT_SUB_EV_TYPE_SHIFT,
+			RTE_EVENT_EV_TYPE_DW);
+	sse_evt[1] = _mm_insert_epi32(sse_evt[1],
+			qes[3].flow_id |
+			qes[3].u.event_type.major << RTE_EVENT_EV_TYPE_SHIFT  |
+			qes[3].u.event_type.sub << RTE_EVENT_SUB_EV_TYPE_SHIFT,
+			RTE_EVENT_EV_TYPE_DW + 2);
+
+	/* Write the sched type to the event metadata. 'op' and 'rsvd' are not
+	 * set:
+	 * sse_evt[0][39:32]  = sched_type_map[qes[0].sched_type] << 6
+	 * sse_evt[0][103:96] = sched_type_map[qes[1].sched_type] << 6
+	 * sse_evt[1][39:32]  = sched_type_map[qes[2].sched_type] << 6
+	 * sse_evt[1][103:96] = sched_type_map[qes[3].sched_type] << 6
+	 */
+#define RTE_EVENT_SCHED_TYPE_BYTE 4
+#define RTE_EVENT_SCHED_TYPE_SHIFT 6
+	sse_evt[0] = _mm_insert_epi8(sse_evt[0],
+		sched_type_map[qes[0].sched_type] << RTE_EVENT_SCHED_TYPE_SHIFT,
+		RTE_EVENT_SCHED_TYPE_BYTE);
+	sse_evt[0] = _mm_insert_epi8(sse_evt[0],
+		sched_type_map[qes[1].sched_type] << RTE_EVENT_SCHED_TYPE_SHIFT,
+		RTE_EVENT_SCHED_TYPE_BYTE + 8);
+	sse_evt[1] = _mm_insert_epi8(sse_evt[1],
+		sched_type_map[qes[2].sched_type] << RTE_EVENT_SCHED_TYPE_SHIFT,
+		RTE_EVENT_SCHED_TYPE_BYTE);
+	sse_evt[1] = _mm_insert_epi8(sse_evt[1],
+		sched_type_map[qes[3].sched_type] << RTE_EVENT_SCHED_TYPE_SHIFT,
+		RTE_EVENT_SCHED_TYPE_BYTE + 8);
+
+	/* Store the metadata to the event (use the double-precision
+	 * _mm_storeh_pd because there is no integer function for storing the
+	 * upper 64b):
+	 * events[0].event = sse_evt[0][63:0]
+	 * events[1].event = sse_evt[0][127:64]
+	 * events[2].event = sse_evt[1][63:0]
+	 * events[3].event = sse_evt[1][127:64]
+	 */
+	_mm_storel_epi64((__m128i *)&events[0].event, sse_evt[0]);
+	_mm_storeh_pd((double *)&events[1].event, (__m128d) sse_evt[0]);
+	_mm_storel_epi64((__m128i *)&events[2].event, sse_evt[1]);
+	_mm_storeh_pd((double *)&events[3].event, (__m128d) sse_evt[1]);
+
+	DLB2_INC_STAT(ev_port->stats.rx_sched_cnt[qes[0].sched_type], 1);
+	DLB2_INC_STAT(ev_port->stats.rx_sched_cnt[qes[1].sched_type], 1);
+	DLB2_INC_STAT(ev_port->stats.rx_sched_cnt[qes[2].sched_type], 1);
+	DLB2_INC_STAT(ev_port->stats.rx_sched_cnt[qes[3].sched_type], 1);
+
+	DLB2_INC_STAT(
+		ev_port->stats.queue[events[0].queue_id].
+			qid_depth[qes[0].qid_depth],
+		1);
+	DLB2_INC_STAT(
+		ev_port->stats.queue[events[1].queue_id].
+			qid_depth[qes[1].qid_depth],
+		1);
+	DLB2_INC_STAT(
+		ev_port->stats.queue[events[2].queue_id].
+			qid_depth[qes[2].qid_depth],
+		1);
+	DLB2_INC_STAT(
+		ev_port->stats.queue[events[3].queue_id].
+			qid_depth[qes[3].qid_depth],
+		1);
+
+	DLB2_INC_STAT(ev_port->stats.traffic.rx_ok, num_events);
+
+	return num_events;
+}
+
+static __rte_always_inline int
+dlb2_recv_qe_sparse(struct dlb2_port *qm_port, struct dlb2_dequeue_qe *qe)
+{
+	volatile struct dlb2_dequeue_qe *cq_addr;
+	uint8_t xor_mask[2] = {0x0F, 0x00};
+	const uint8_t and_mask = 0x0F;
+	__m128i *qes = (__m128i *)qe;
+	uint8_t gen_bits, gen_bit;
+	uintptr_t addr[4];
+	uint16_t idx;
+
+	cq_addr = dlb2_port[qm_port->id][PORT_TYPE(qm_port)].cq_base;
+
+	idx = qm_port->cq_idx;
+
+	/* Load the next 4 QEs */
+	addr[0] = (uintptr_t)&cq_addr[idx];
+	addr[1] = (uintptr_t)&cq_addr[(idx +  4) & qm_port->cq_depth_mask];
+	addr[2] = (uintptr_t)&cq_addr[(idx +  8) & qm_port->cq_depth_mask];
+	addr[3] = (uintptr_t)&cq_addr[(idx + 12) & qm_port->cq_depth_mask];
+
+	/* Prefetch next batch of QEs (all CQs occupy minimum 8 cache lines) */
+	rte_prefetch0(&cq_addr[(idx + 16) & qm_port->cq_depth_mask]);
+	rte_prefetch0(&cq_addr[(idx + 20) & qm_port->cq_depth_mask]);
+	rte_prefetch0(&cq_addr[(idx + 24) & qm_port->cq_depth_mask]);
+	rte_prefetch0(&cq_addr[(idx + 28) & qm_port->cq_depth_mask]);
+
+	/* Correct the xor_mask for wrap-around QEs */
+	gen_bit = qm_port->gen_bit;
+	xor_mask[gen_bit] ^= !!((idx +  4) > qm_port->cq_depth_mask) << 1;
+	xor_mask[gen_bit] ^= !!((idx +  8) > qm_port->cq_depth_mask) << 2;
+	xor_mask[gen_bit] ^= !!((idx + 12) > qm_port->cq_depth_mask) << 3;
+
+	/* Read the cache lines backwards to ensure that if QE[N] (N > 0) is
+	 * valid, then QEs[0:N-1] are too.
+	 */
+	qes[3] = _mm_load_si128((__m128i *)(void *)addr[3]);
+	rte_compiler_barrier();
+	qes[2] = _mm_load_si128((__m128i *)(void *)addr[2]);
+	rte_compiler_barrier();
+	qes[1] = _mm_load_si128((__m128i *)(void *)addr[1]);
+	rte_compiler_barrier();
+	qes[0] = _mm_load_si128((__m128i *)(void *)addr[0]);
+
+	/* Extract and combine the gen bits */
+	gen_bits = ((_mm_extract_epi8(qes[0], 15) & 0x1) << 0) |
+		   ((_mm_extract_epi8(qes[1], 15) & 0x1) << 1) |
+		   ((_mm_extract_epi8(qes[2], 15) & 0x1) << 2) |
+		   ((_mm_extract_epi8(qes[3], 15) & 0x1) << 3);
+
+	/* XOR the combined bits such that a 1 represents a valid QE */
+	gen_bits ^= xor_mask[gen_bit];
+
+	/* Mask off gen bits we don't care about */
+	gen_bits &= and_mask;
+
+	return __builtin_popcount(gen_bits);
+}
+
+static inline void
+dlb2_inc_cq_idx(struct dlb2_port *qm_port, int cnt)
+{
+	uint16_t idx = qm_port->cq_idx_unmasked + cnt;
+
+	qm_port->cq_idx_unmasked = idx;
+	qm_port->cq_idx = idx & qm_port->cq_depth_mask;
+	qm_port->gen_bit = (~(idx >> qm_port->gen_bit_shift)) & 0x1;
+}
+
+static int
+dlb2_event_release(struct dlb2_eventdev *dlb2,
+		   uint8_t port_id,
+		   int n)
+{
+	struct process_local_port_data *port_data;
+	struct dlb2_eventdev_port *ev_port;
+	struct dlb2_port *qm_port;
+	int i, cnt;
+
+	if (port_id > dlb2->num_ports) {
+		DLB2_LOG_ERR("Invalid port id %d in dlb2-event_release\n",
+			     port_id);
+		rte_errno = -EINVAL;
+		return rte_errno;
+	}
+
+	ev_port = &dlb2->ev_ports[port_id];
+	qm_port = &ev_port->qm_port;
+	port_data = &dlb2_port[qm_port->id][PORT_TYPE(qm_port)];
+
+	cnt = 0;
+
+	if (qm_port->is_directed) {
+		cnt = n;
+		goto sw_credit_update;
+	}
+
+	for (i = 0; i < n; i += DLB2_NUM_QES_PER_CACHE_LINE) {
+		int j;
+
+		/* Zero-out QEs */
+		qm_port->qe4[0].cmd_byte = 0;
+		qm_port->qe4[1].cmd_byte = 0;
+		qm_port->qe4[2].cmd_byte = 0;
+		qm_port->qe4[3].cmd_byte = 0;
+
+		for (j = 0; j < DLB2_NUM_QES_PER_CACHE_LINE && (i + j) < n; j++)
+			qm_port->qe4[j].cmd_byte = DLB2_COMP_CMD_BYTE;
+
+		qm_port->issued_releases += j;
+
+		if (j == 0)
+			break;
+
+		if (qm_port->token_pop_mode == DELAYED_POP && j < 4 &&
+		    qm_port->issued_releases >= qm_port->token_pop_thresh - 1) {
+			dlb2_construct_token_pop_qe(qm_port, j);
+
+			/* Reset the releases counter for the next QE batch */
+			qm_port->issued_releases -= qm_port->token_pop_thresh;
+		}
+
+		dlb2_hw_do_enqueue(qm_port, i == 0, port_data);
+
+		cnt += j;
+	}
+
+	if (qm_port->token_pop_mode == DELAYED_POP &&
+	    qm_port->issued_releases >= qm_port->token_pop_thresh - 1) {
+		dlb2_consume_qe_immediate(qm_port, qm_port->owed_tokens);
+		qm_port->issued_releases -= qm_port->token_pop_thresh;
+	}
+
+sw_credit_update:
+	/* each release returns one credit */
+	if (!ev_port->outstanding_releases) {
+		DLB2_LOG_ERR("Unrecoverable application error. Outstanding releases underflowed.\n");
+		rte_errno = -ENOTRECOVERABLE;
+		return rte_errno;
+	}
+
+	ev_port->outstanding_releases -= cnt;
+	ev_port->inflight_credits += cnt;
+
+	/* Replenish s/w credits if enough releases are performed */
+	dlb2_replenish_sw_credits(dlb2, ev_port);
+	return 0;
+}
+
+static inline int16_t
+dlb2_hw_dequeue_sparse(struct dlb2_eventdev *dlb2,
+		       struct dlb2_eventdev_port *ev_port,
+		       struct rte_event *events,
+		       uint16_t max_num,
+		       uint64_t dequeue_timeout_ticks)
+{
+	uint64_t timeout;
+	uint64_t start_ticks = 0ULL;
+	struct dlb2_port *qm_port;
+	int num = 0;
+
+	qm_port = &ev_port->qm_port;
+
+	/* We have a special implementation for waiting. Wait can be:
+	 * 1) no waiting at all
+	 * 2) busy poll only
+	 * 3) wait for interrupt. If wakeup and poll time
+	 * has expired, then return to caller
+	 * 4) umonitor/umwait repeatedly up to poll time
+	 */
+
+	/* If configured for per dequeue wait, then use wait value provided
+	 * to this API. Otherwise we must use the global
+	 * value from eventdev config time.
+	 */
+	if (!dlb2->global_dequeue_wait)
+		timeout = dequeue_timeout_ticks;
+	else
+		timeout = dlb2->global_dequeue_wait_ticks;
+
+	start_ticks = rte_get_timer_cycles();
+
+	while (num < max_num) {
+		struct dlb2_dequeue_qe qes[DLB2_NUM_QES_PER_CACHE_LINE];
+		int num_avail;
+
+		/* Copy up to 4 QEs from the current cache line into qes */
+		num_avail = dlb2_recv_qe_sparse(qm_port, qes);
+
+		/* But don't process more than the user requested */
+		num_avail = RTE_MIN(num_avail, max_num - num);
+
+		dlb2_inc_cq_idx(qm_port, num_avail << 2);
+
+		if (num_avail == DLB2_NUM_QES_PER_CACHE_LINE)
+			num += dlb2_process_dequeue_four_qes(ev_port,
+							      qm_port,
+							      &events[num],
+							      &qes[0]);
+		else if (num_avail)
+			num += dlb2_process_dequeue_qes(ev_port,
+							 qm_port,
+							 &events[num],
+							 &qes[0],
+							 num_avail);
+		else if ((timeout == 0) || (num > 0))
+			/* Not waiting in any form, or 1+ events received? */
+			break;
+		else if (dlb2_dequeue_wait(dlb2, ev_port, qm_port,
+					   timeout, start_ticks))
+			break;
+	}
+
+	qm_port->owed_tokens += num;
+
+	if (num) {
+		if (qm_port->token_pop_mode == AUTO_POP)
+			dlb2_consume_qe_immediate(qm_port, num);
+
+		ev_port->outstanding_releases += num;
+
+		dlb2_port_credits_inc(qm_port, num);
+	}
+
+	return num;
+}
+
+static __rte_always_inline int
+dlb2_recv_qe(struct dlb2_port *qm_port, struct dlb2_dequeue_qe *qe,
+	     uint8_t *offset)
+{
+	uint8_t xor_mask[2][4] = { {0x0F, 0x0E, 0x0C, 0x08},
+				   {0x00, 0x01, 0x03, 0x07} };
+	uint8_t and_mask[4] = {0x0F, 0x0E, 0x0C, 0x08};
+	volatile struct dlb2_dequeue_qe *cq_addr;
+	__m128i *qes = (__m128i *)qe;
+	uint64_t *cache_line_base;
+	uint8_t gen_bits;
+
+	cq_addr = dlb2_port[qm_port->id][PORT_TYPE(qm_port)].cq_base;
+	cq_addr = &cq_addr[qm_port->cq_idx];
+
+	cache_line_base = (void *)(((uintptr_t)cq_addr) & ~0x3F);
+	*offset = ((uintptr_t)cq_addr & 0x30) >> 4;
+
+	/* Load the next CQ cache line from memory. Pack these reads as tight
+	 * as possible to reduce the chance that DLB invalidates the line while
+	 * the CPU is reading it. Read the cache line backwards to ensure that
+	 * if QE[N] (N > 0) is valid, then QEs[0:N-1] are too.
+	 *
+	 * (Valid QEs start at &qe[offset])
+	 */
+	qes[3] = _mm_load_si128((__m128i *)&cache_line_base[6]);
+	qes[2] = _mm_load_si128((__m128i *)&cache_line_base[4]);
+	qes[1] = _mm_load_si128((__m128i *)&cache_line_base[2]);
+	qes[0] = _mm_load_si128((__m128i *)&cache_line_base[0]);
+
+	/* Evict the cache line ASAP */
+	dlb2_cldemote(cache_line_base);
+
+	/* Extract and combine the gen bits */
+	gen_bits = ((_mm_extract_epi8(qes[0], 15) & 0x1) << 0) |
+		   ((_mm_extract_epi8(qes[1], 15) & 0x1) << 1) |
+		   ((_mm_extract_epi8(qes[2], 15) & 0x1) << 2) |
+		   ((_mm_extract_epi8(qes[3], 15) & 0x1) << 3);
+
+	/* XOR the combined bits such that a 1 represents a valid QE */
+	gen_bits ^= xor_mask[qm_port->gen_bit][*offset];
+
+	/* Mask off gen bits we don't care about */
+	gen_bits &= and_mask[*offset];
+
+	return __builtin_popcount(gen_bits);
+}
+
+static inline int16_t
+dlb2_hw_dequeue(struct dlb2_eventdev *dlb2,
+		struct dlb2_eventdev_port *ev_port,
+		struct rte_event *events,
+		uint16_t max_num,
+		uint64_t dequeue_timeout_ticks)
+{
+	uint64_t timeout;
+	uint64_t start_ticks = 0ULL;
+	struct dlb2_port *qm_port;
+	int num = 0;
+
+	qm_port = &ev_port->qm_port;
+
+	/* We have a special implementation for waiting. Wait can be:
+	 * 1) no waiting at all
+	 * 2) busy poll only
+	 * 3) wait for interrupt. If wakeup and poll time
+	 * has expired, then return to caller
+	 * 4) umonitor/umwait repeatedly up to poll time
+	 */
+
+	/* If configured for per dequeue wait, then use wait value provided
+	 * to this API. Otherwise we must use the global
+	 * value from eventdev config time.
+	 */
+	if (!dlb2->global_dequeue_wait)
+		timeout = dequeue_timeout_ticks;
+	else
+		timeout = dlb2->global_dequeue_wait_ticks;
+
+	start_ticks = rte_get_timer_cycles();
+
+	while (num < max_num) {
+		struct dlb2_dequeue_qe qes[DLB2_NUM_QES_PER_CACHE_LINE];
+		uint8_t offset;
+		int num_avail;
+
+		/* Copy up to 4 QEs from the current cache line into qes */
+		num_avail = dlb2_recv_qe(qm_port, qes, &offset);
+
+		/* But don't process more than the user requested */
+		num_avail = RTE_MIN(num_avail, max_num - num);
+
+		dlb2_inc_cq_idx(qm_port, num_avail);
+
+		if (num_avail == DLB2_NUM_QES_PER_CACHE_LINE)
+			num += dlb2_process_dequeue_four_qes(ev_port,
+							     qm_port,
+							     &events[num],
+							     &qes[offset]);
+		else if (num_avail)
+			num += dlb2_process_dequeue_qes(ev_port,
+							qm_port,
+							&events[num],
+							&qes[offset],
+							num_avail);
+		else if ((timeout == 0) || (num > 0))
+			/* Not waiting in any form, or 1+ events received? */
+			break;
+		else if (dlb2_dequeue_wait(dlb2, ev_port, qm_port,
+					   timeout, start_ticks))
+			break;
+	}
+
+	qm_port->owed_tokens += num;
+
+	if (num) {
+		if (qm_port->token_pop_mode == AUTO_POP)
+			dlb2_consume_qe_immediate(qm_port, num);
+
+		ev_port->outstanding_releases += num;
+
+		dlb2_port_credits_inc(qm_port, num);
+	}
+
+	return num;
+}
+
+static uint16_t
+dlb2_event_dequeue_burst(void *event_port, struct rte_event *ev, uint16_t num,
+			 uint64_t wait)
+{
+	struct dlb2_eventdev_port *ev_port = event_port;
+	struct dlb2_port *qm_port = &ev_port->qm_port;
+	struct dlb2_eventdev *dlb2 = ev_port->dlb2;
+	uint16_t cnt;
+
+	RTE_ASSERT(ev_port->setup_done);
+	RTE_ASSERT(ev != NULL);
+
+	if (ev_port->implicit_release && ev_port->outstanding_releases > 0) {
+		uint16_t out_rels = ev_port->outstanding_releases;
+
+		if (dlb2_event_release(dlb2, ev_port->id, out_rels))
+			return 0; /* rte_errno is set */
+
+		DLB2_INC_STAT(ev_port->stats.tx_implicit_rel, out_rels);
+	}
+
+	if (qm_port->token_pop_mode == DEFERRED_POP && qm_port->owed_tokens)
+		dlb2_consume_qe_immediate(qm_port, qm_port->owed_tokens);
+
+	cnt = dlb2_hw_dequeue(dlb2, ev_port, ev, num, wait);
+
+	DLB2_INC_STAT(ev_port->stats.traffic.total_polls, 1);
+	DLB2_INC_STAT(ev_port->stats.traffic.zero_polls, ((cnt == 0) ? 1 : 0));
+
+	return cnt;
+}
+
+static uint16_t
+dlb2_event_dequeue(void *event_port, struct rte_event *ev, uint64_t wait)
+{
+	return dlb2_event_dequeue_burst(event_port, ev, 1, wait);
+}
+
+static uint16_t
+dlb2_event_dequeue_burst_sparse(void *event_port, struct rte_event *ev,
+				uint16_t num, uint64_t wait)
+{
+	struct dlb2_eventdev_port *ev_port = event_port;
+	struct dlb2_port *qm_port = &ev_port->qm_port;
+	struct dlb2_eventdev *dlb2 = ev_port->dlb2;
+	uint16_t cnt;
+
+	RTE_ASSERT(ev_port->setup_done);
+	RTE_ASSERT(ev != NULL);
+
+	if (ev_port->implicit_release && ev_port->outstanding_releases > 0) {
+		uint16_t out_rels = ev_port->outstanding_releases;
+
+		if (dlb2_event_release(dlb2, ev_port->id, out_rels))
+			return 0; /* rte_errno is set */
+
+		DLB2_INC_STAT(ev_port->stats.tx_implicit_rel, out_rels);
+	}
+
+	if (qm_port->token_pop_mode == DEFERRED_POP && qm_port->owed_tokens)
+		dlb2_consume_qe_immediate(qm_port, qm_port->owed_tokens);
+
+	cnt = dlb2_hw_dequeue_sparse(dlb2, ev_port, ev, num, wait);
+
+	DLB2_INC_STAT(ev_port->stats.traffic.total_polls, 1);
+	DLB2_INC_STAT(ev_port->stats.traffic.zero_polls, ((cnt == 0) ? 1 : 0));
+	return cnt;
+}
+
+static uint16_t
+dlb2_event_dequeue_sparse(void *event_port, struct rte_event *ev,
+			  uint64_t wait)
+{
+	return dlb2_event_dequeue_burst_sparse(event_port, ev, 1, wait);
+}
+
 static void
 dlb2_entry_points_init(struct rte_eventdev *dev)
 {
+	struct dlb2_eventdev *dlb2;
+
 	/* Expose PMD's eventdev interface */
 	static struct rte_eventdev_ops dlb2_eventdev_entry_ops = {
 		.dev_infos_get    = dlb2_eventdev_info_get,
@@ -2781,6 +3558,15 @@ dlb2_entry_points_init(struct rte_eventdev *dev)
 	dev->enqueue_burst = dlb2_event_enqueue_burst;
 	dev->enqueue_new_burst = dlb2_event_enqueue_new_burst;
 	dev->enqueue_forward_burst = dlb2_event_enqueue_forward_burst;
+
+	dlb2 = dev->data->dev_private;
+	if (dlb2->poll_mode == DLB2_CQ_POLL_MODE_SPARSE) {
+		dev->dequeue = dlb2_event_dequeue_sparse;
+		dev->dequeue_burst = dlb2_event_dequeue_burst_sparse;
+	} else {
+		dev->dequeue = dlb2_event_dequeue;
+		dev->dequeue_burst = dlb2_event_dequeue_burst;
+	}
 }
 
 int
-- 
2.6.4