[dpdk-dev] [PATCH 0/3] Add dual threading in QAT PMD

[dpdk-dev] [PATCH 0/3] Add dual threading in QAT PMD

[Fiona Trahe]

Remove the limitation whereby enqueue and dequeue must be
done in same thread.
The inflight calculation is reworked to be thread-safe for 2
threads - note this is not general multi-thread support, i.e
all enqueues to a qp must still be done in one thread and
all dequeues must be done in one thread, but enqueues and
dequeues may be in separate threads.
As the tail-coalescing feature is not
threadsafe it is removed first.

Fiona Trahe (3):
  common/qat: remove tail write coalescing feature
  common/qat: move max inflights param into qp
  common/qat: add dual thread support

 doc/guides/compressdevs/qat_comp.rst |    5 ++-
 doc/guides/cryptodevs/qat.rst        |   11 ++++-
 drivers/common/qat/qat_qp.c          |   77 +++++++++++++++++-----------------
 drivers/common/qat/qat_qp.h          |   11 +----
 4 files changed, 54 insertions(+), 50 deletions(-)

[dpdk-dev] [PATCH 1/3] common/qat: remove tail write coalescing feature

[Fiona Trahe]

The feature Coalescing Tail Writes on Enqueue is removed
as it is not thread-safe and a dual-thread feature will be added shortly.

Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
---
 drivers/common/qat/qat_qp.c |   16 +++-------------
 drivers/common/qat/qat_qp.h |    6 ------
 2 files changed, 3 insertions(+), 19 deletions(-)

diff --git a/drivers/common/qat/qat_qp.c b/drivers/common/qat/qat_qp.c
index 03f11f8..01ddce0 100644
--- a/drivers/common/qat/qat_qp.c
+++ b/drivers/common/qat/qat_qp.c
@@ -538,7 +538,6 @@ static inline uint32_t adf_modulo(uint32_t data, uint32_t modulo_mask)
 txq_write_tail(struct qat_qp *qp, struct qat_queue *q) {
 	WRITE_CSR_RING_TAIL(qp->mmap_bar_addr, q->hw_bundle_number,
 			q->hw_queue_number, q->tail);
-	q->nb_pending_requests = 0;
 	q->csr_tail = q->tail;
 }
 
@@ -622,25 +621,20 @@ void rxq_free_desc(struct qat_qp *qp, struct qat_queue *q)
 kick_tail:
 	queue->tail = tail;
 	tmp_qp->stats.enqueued_count += nb_ops_sent;
-	queue->nb_pending_requests += nb_ops_sent;
-	if (tmp_qp->inflights16 < QAT_CSR_TAIL_FORCE_WRITE_THRESH ||
-		    queue->nb_pending_requests > QAT_CSR_TAIL_WRITE_THRESH) {
-		txq_write_tail(tmp_qp, queue);
-	}
+	txq_write_tail(tmp_qp, queue);
 	return nb_ops_sent;
 }
 
 uint16_t
 qat_dequeue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 {
-	struct qat_queue *rx_queue, *tx_queue;
+	struct qat_queue *rx_queue;
 	struct qat_qp *tmp_qp = (struct qat_qp *)qp;
 	uint32_t head;
 	uint32_t resp_counter = 0;
 	uint8_t *resp_msg;
 
 	rx_queue = &(tmp_qp->rx_q);
-	tx_queue = &(tmp_qp->tx_q);
 	head = rx_queue->head;
 	resp_msg = (uint8_t *)rx_queue->base_addr + rx_queue->head;
 
@@ -677,11 +671,7 @@ void rxq_free_desc(struct qat_qp *qp, struct qat_queue *q)
 						QAT_CSR_HEAD_WRITE_THRESH)
 			rxq_free_desc(tmp_qp, rx_queue);
 	}
-	/* also check if tail needs to be advanced */
-	if (tmp_qp->inflights16 <= QAT_CSR_TAIL_FORCE_WRITE_THRESH &&
-		tx_queue->tail != tx_queue->csr_tail) {
-		txq_write_tail(tmp_qp, tx_queue);
-	}
+
 	return resp_counter;
 }
 
diff --git a/drivers/common/qat/qat_qp.h b/drivers/common/qat/qat_qp.h
index 980c2ba..9212ca4 100644
--- a/drivers/common/qat/qat_qp.h
+++ b/drivers/common/qat/qat_qp.h
@@ -11,10 +11,6 @@
 
 #define QAT_CSR_HEAD_WRITE_THRESH 32U
 /* number of requests to accumulate before writing head CSR */
-#define QAT_CSR_TAIL_WRITE_THRESH 32U
-/* number of requests to accumulate before writing tail CSR */
-#define QAT_CSR_TAIL_FORCE_WRITE_THRESH 256U
-/* number of inflights below which no tail write coalescing should occur */
 
 typedef int (*build_request_t)(void *op,
 		uint8_t *req, void *op_cookie,
@@ -64,8 +60,6 @@ struct qat_queue {
 	uint32_t	csr_tail;		/* last written tail value */
 	uint16_t	nb_processed_responses;
 	/* number of responses processed since last CSR head write */
-	uint16_t	nb_pending_requests;
-	/* number of requests pending since last CSR tail write */
 };
 
 struct qat_qp {
-- 
1.7.0.7

[dpdk-dev] [PATCH 2/3] common/qat: move max inflights param into qp

[Fiona Trahe]

The max_inflights parameter is moved from qat_queue to qat_qp as it's
a more appropriate location.

Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
---
 drivers/common/qat/qat_qp.c |   23 ++++++++++++-----------
 drivers/common/qat/qat_qp.h |    2 +-
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/common/qat/qat_qp.c b/drivers/common/qat/qat_qp.c
index 01ddce0..8e4c74a 100644
--- a/drivers/common/qat/qat_qp.c
+++ b/drivers/common/qat/qat_qp.c
@@ -239,6 +239,15 @@ int qat_qp_setup(struct qat_pci_device *qat_dev,
 		goto create_err;
 	}
 
+	qp->max_inflights = ADF_MAX_INFLIGHTS(qp->tx_q.queue_size,
+				ADF_BYTES_TO_MSG_SIZE(qp->tx_q.msg_size));
+
+	if (qp->max_inflights < 2) {
+		QAT_LOG(ERR, "Invalid num inflights");
+		qat_queue_delete(&(qp->tx_q));
+		goto create_err;
+	}
+
 	if (qat_queue_create(qat_dev, &(qp->rx_q), qat_qp_conf,
 					ADF_RING_DIR_RX) != 0) {
 		QAT_LOG(ERR, "Rx queue create failed "
@@ -416,15 +425,7 @@ static void qat_queue_delete(struct qat_queue *queue)
 		goto queue_create_err;
 	}
 
-	queue->max_inflights = ADF_MAX_INFLIGHTS(queue->queue_size,
-					ADF_BYTES_TO_MSG_SIZE(desc_size));
 	queue->modulo_mask = (1 << ADF_RING_SIZE_MODULO(queue->queue_size)) - 1;
-
-	if (queue->max_inflights < 2) {
-		QAT_LOG(ERR, "Invalid num inflights");
-		ret = -EINVAL;
-		goto queue_create_err;
-	}
 	queue->head = 0;
 	queue->tail = 0;
 	queue->msg_size = desc_size;
@@ -443,11 +444,11 @@ static void qat_queue_delete(struct qat_queue *queue)
 			queue->hw_queue_number, queue_base);
 
 	QAT_LOG(DEBUG, "RING: Name:%s, size in CSR: %u, in bytes %u,"
-		" nb msgs %u, msg_size %u, max_inflights %u modulo mask %u",
+		" nb msgs %u, msg_size %u, modulo mask %u",
 			queue->memz_name,
 			queue->queue_size, queue_size_bytes,
 			qp_conf->nb_descriptors, desc_size,
-			queue->max_inflights, queue->modulo_mask);
+			queue->modulo_mask);
 
 	return 0;
 
@@ -590,7 +591,7 @@ void rxq_free_desc(struct qat_qp *qp, struct qat_queue *q)
 
 	/* Find how many can actually fit on the ring */
 	tmp_qp->inflights16 += nb_ops;
-	overflow = tmp_qp->inflights16 - queue->max_inflights;
+	overflow = tmp_qp->inflights16 - tmp_qp->max_inflights;
 	if (overflow > 0) {
 		tmp_qp->inflights16 -= overflow;
 		nb_ops_possible = nb_ops - overflow;
diff --git a/drivers/common/qat/qat_qp.h b/drivers/common/qat/qat_qp.h
index 9212ca4..5066f06 100644
--- a/drivers/common/qat/qat_qp.h
+++ b/drivers/common/qat/qat_qp.h
@@ -51,7 +51,6 @@ struct qat_queue {
 	uint32_t	tail;			/* Shadow copy of the tail */
 	uint32_t	modulo_mask;
 	uint32_t	msg_size;
-	uint16_t	max_inflights;
 	uint32_t	queue_size;
 	uint8_t		hw_bundle_number;
 	uint8_t		hw_queue_number;
@@ -76,6 +75,7 @@ struct qat_qp {
 	enum qat_service_type service_type;
 	struct qat_pci_device *qat_dev;
 	/**< qat device this qp is on */
+	uint16_t max_inflights;
 } __rte_cache_aligned;
 
 extern const struct qat_qp_hw_data qat_gen1_qps[][ADF_MAX_QPS_ON_ANY_SERVICE];
-- 
1.7.0.7

[dpdk-dev] [PATCH 3/3] common/qat: add dual thread support

[Fiona Trahe]

Remove the limitation whereby enqueue and dequeue must be
done in same thread.
The inflight calculation is reworked to be thread-safe for 2
threads - note this is not general multi-thread support, i.e
all enqueues to a qp must still be done in one thread and
all dequeues must be done in one thread, but enqueues and
dequeues may be in separate threads.
Documentation updated.

Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
---
 doc/guides/compressdevs/qat_comp.rst |    5 +++-
 doc/guides/cryptodevs/qat.rst        |   11 +++++++-
 drivers/common/qat/qat_qp.c          |   40 ++++++++++++++++++++-------------
 drivers/common/qat/qat_qp.h          |    3 +-
 4 files changed, 39 insertions(+), 20 deletions(-)

diff --git a/doc/guides/compressdevs/qat_comp.rst b/doc/guides/compressdevs/qat_comp.rst
index 6f583a4..d06b08a 100644
--- a/doc/guides/compressdevs/qat_comp.rst
+++ b/doc/guides/compressdevs/qat_comp.rst
@@ -33,7 +33,10 @@ Limitations
 -----------
 
 * Compressdev level 0, no compression, is not supported.
-* Queue pairs are not thread-safe (that is, within a single queue pair, RX and TX from different lcores is not supported).
+* Queue-pairs are thread-safe on Intel CPUs but Queues are not (that is, within a single
+  queue-pair all enqueues to the TX queue must be done from one thread and all dequeues
+  from the RX queue must be done from one thread, but enqueues and dequeues may be done
+  in different threads.)
 * No BSD support as BSD QAT kernel driver not available.
 * When using Deflate dynamic huffman encoding for compression, the input size (op.src.length)
   must be < CONFIG_RTE_PMD_QAT_COMP_IM_BUFFER_SIZE from the config file,
diff --git a/doc/guides/cryptodevs/qat.rst b/doc/guides/cryptodevs/qat.rst
index e905f6d..7c81b9b 100644
--- a/doc/guides/cryptodevs/qat.rst
+++ b/doc/guides/cryptodevs/qat.rst
@@ -81,7 +81,11 @@ Limitations
 * No BSD support as BSD QAT kernel driver not available.
 * ZUC EEA3/EIA3 is not supported by dh895xcc devices
 * Maximum additional authenticated data (AAD) for GCM is 240 bytes long and must be passed to the device in a buffer rounded up to the nearest block-size multiple (x16) and padded with zeros.
-* Queue pairs are not thread-safe (that is, within a single queue pair, RX and TX from different lcores is not supported).
+* Queue-pairs are thread-safe on Intel CPUs but Queues are not (that is, within a single
+  queue-pair all enqueues to the TX queue must be done from one thread and all dequeues
+  from the RX queue must be done from one thread, but enqueues and dequeues may be done
+  in different threads.)
+
 
 Extra notes on KASUMI F9
 ~~~~~~~~~~~~~~~~~~~~~~~~
@@ -122,7 +126,10 @@ Limitations
 ~~~~~~~~~~~
 
 * Big integers longer than 4096 bits are not supported.
-* Queue pairs are not thread-safe (that is, within a single queue pair, RX and TX from different lcores is not supported).
+* Queue-pairs are thread-safe on Intel CPUs but Queues are not (that is, within a single
+  queue-pair all enqueues to the TX queue must be done from one thread and all dequeues
+  from the RX queue must be done from one thread, but enqueues and dequeues may be done
+  in different threads.)
 
 .. _building_qat:
 
diff --git a/drivers/common/qat/qat_qp.c b/drivers/common/qat/qat_qp.c
index 8e4c74a..30cdc61 100644
--- a/drivers/common/qat/qat_qp.c
+++ b/drivers/common/qat/qat_qp.c
@@ -230,7 +230,7 @@ int qat_qp_setup(struct qat_pci_device *qat_dev,
 	}
 
 	qp->mmap_bar_addr = pci_dev->mem_resource[0].addr;
-	qp->inflights16 = 0;
+	qp->enqueued = qp->dequeued = 0;
 
 	if (qat_queue_create(qat_dev, &(qp->tx_q), qat_qp_conf,
 					ADF_RING_DIR_TX) != 0) {
@@ -321,7 +321,7 @@ int qat_qp_release(struct qat_qp **qp_addr)
 				qp->qat_dev->qat_dev_id);
 
 	/* Don't free memory if there are still responses to be processed */
-	if (qp->inflights16 == 0) {
+	if ((qp->enqueued - qp->dequeued) == 0) {
 		qat_queue_delete(&(qp->tx_q));
 		qat_queue_delete(&(qp->rx_q));
 	} else {
@@ -579,7 +579,6 @@ void rxq_free_desc(struct qat_qp *qp, struct qat_queue *q)
 	uint16_t nb_ops_possible = nb_ops;
 	register uint8_t *base_addr;
 	register uint32_t tail;
-	int overflow;
 
 	if (unlikely(nb_ops == 0))
 		return 0;
@@ -590,13 +589,25 @@ void rxq_free_desc(struct qat_qp *qp, struct qat_queue *q)
 	tail = queue->tail;
 
 	/* Find how many can actually fit on the ring */
-	tmp_qp->inflights16 += nb_ops;
-	overflow = tmp_qp->inflights16 - tmp_qp->max_inflights;
-	if (overflow > 0) {
-		tmp_qp->inflights16 -= overflow;
-		nb_ops_possible = nb_ops - overflow;
-		if (nb_ops_possible == 0)
-			return 0;
+	{
+		/* dequeued can only be written by one thread, but it may not
+		 * be this thread. As it's 4-byte aligned it will be read
+		 * atomically here by any Intel CPU.
+		 * enqueued can wrap before dequeued, but cannot
+		 * lap it as var size of enq/deq (uint32_t) > var size of
+		 * max_inflights (uint16_t). In reality inflights is never
+		 * even as big as max uint16_t, as it's <= ADF_MAX_DESC.
+		 * On wrapping, the calculation still returns the correct
+		 * positive value as all three vars are unsigned.
+		 */
+		uint32_t inflights =
+			tmp_qp->enqueued - tmp_qp->dequeued;
+
+		if ((inflights + nb_ops) > tmp_qp->max_inflights) {
+			nb_ops_possible = tmp_qp->max_inflights - inflights;
+			if (nb_ops_possible == 0)
+				return 0;
+		}
 	}
 
 	while (nb_ops_sent != nb_ops_possible) {
@@ -605,11 +616,7 @@ void rxq_free_desc(struct qat_qp *qp, struct qat_queue *q)
 				tmp_qp->qat_dev_gen);
 		if (ret != 0) {
 			tmp_qp->stats.enqueue_err_count++;
-			/*
-			 * This message cannot be enqueued,
-			 * decrease number of ops that wasn't sent
-			 */
-			tmp_qp->inflights16 -= nb_ops_possible - nb_ops_sent;
+			/* This message cannot be enqueued */
 			if (nb_ops_sent == 0)
 				return 0;
 			goto kick_tail;
@@ -621,6 +628,7 @@ void rxq_free_desc(struct qat_qp *qp, struct qat_queue *q)
 	}
 kick_tail:
 	queue->tail = tail;
+	tmp_qp->enqueued += nb_ops_sent;
 	tmp_qp->stats.enqueued_count += nb_ops_sent;
 	txq_write_tail(tmp_qp, queue);
 	return nb_ops_sent;
@@ -664,9 +672,9 @@ void rxq_free_desc(struct qat_qp *qp, struct qat_queue *q)
 	}
 	if (resp_counter > 0) {
 		rx_queue->head = head;
+		tmp_qp->dequeued += resp_counter;
 		tmp_qp->stats.dequeued_count += resp_counter;
 		rx_queue->nb_processed_responses += resp_counter;
-		tmp_qp->inflights16 -= resp_counter;
 
 		if (rx_queue->nb_processed_responses >
 						QAT_CSR_HEAD_WRITE_THRESH)
diff --git a/drivers/common/qat/qat_qp.h b/drivers/common/qat/qat_qp.h
index 5066f06..8b9ab79 100644
--- a/drivers/common/qat/qat_qp.h
+++ b/drivers/common/qat/qat_qp.h
@@ -63,7 +63,6 @@ struct qat_queue {
 
 struct qat_qp {
 	void			*mmap_bar_addr;
-	uint16_t		inflights16;
 	struct qat_queue	tx_q;
 	struct qat_queue	rx_q;
 	struct qat_common_stats stats;
@@ -75,6 +74,8 @@ struct qat_qp {
 	enum qat_service_type service_type;
 	struct qat_pci_device *qat_dev;
 	/**< qat device this qp is on */
+	uint32_t enqueued;
+	uint32_t dequeued __rte_aligned(4);
 	uint16_t max_inflights;
 } __rte_cache_aligned;
 
-- 
1.7.0.7

[dpdk-dev] [PATCH v2 0/3] Add dual threading in QAT PMD

[Fiona Trahe]

Remove the limitation whereby enqueue and dequeue must be
done in same thread.
The inflight calculation is reworked to be thread-safe for 2
threads - note this is not general multi-thread support, i.e
all enqueues to a qp must still be done in one thread and
all dequeues must be done in one thread, but enqueues and
dequeues may be in separate threads.
As the tail-coalescing feature is not
threadsafe it is removed first.

v2 changes:
 - clarified wording in docs

Fiona Trahe (3):
  common/qat: remove tail write coalescing feature
  common/qat: move max inflights param into qp
  common/qat: add dual thread support

 doc/guides/compressdevs/qat_comp.rst |  5 ++-
 doc/guides/cryptodevs/qat.rst        | 11 +++++-
 drivers/common/qat/qat_qp.c          | 77 ++++++++++++++++++------------------
 drivers/common/qat/qat_qp.h          | 11 ++----
 4 files changed, 54 insertions(+), 50 deletions(-)

-- 
2.13.6

[dpdk-dev] [PATCH v2 1/3] common/qat: remove tail write coalescing feature

[Fiona Trahe]

The feature Coalescing Tail Writes on Enqueue is removed
as it is not thread-safe and a dual-thread feature will be added shortly.

Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
---
 drivers/common/qat/qat_qp.c | 16 +++-------------
 drivers/common/qat/qat_qp.h |  6 ------
 2 files changed, 3 insertions(+), 19 deletions(-)

diff --git a/drivers/common/qat/qat_qp.c b/drivers/common/qat/qat_qp.c
index 03f11f869..01ddce008 100644
--- a/drivers/common/qat/qat_qp.c
+++ b/drivers/common/qat/qat_qp.c
@@ -538,7 +538,6 @@ static inline void
 txq_write_tail(struct qat_qp *qp, struct qat_queue *q) {
 	WRITE_CSR_RING_TAIL(qp->mmap_bar_addr, q->hw_bundle_number,
 			q->hw_queue_number, q->tail);
-	q->nb_pending_requests = 0;
 	q->csr_tail = q->tail;
 }
 
@@ -622,25 +621,20 @@ qat_enqueue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 kick_tail:
 	queue->tail = tail;
 	tmp_qp->stats.enqueued_count += nb_ops_sent;
-	queue->nb_pending_requests += nb_ops_sent;
-	if (tmp_qp->inflights16 < QAT_CSR_TAIL_FORCE_WRITE_THRESH ||
-		    queue->nb_pending_requests > QAT_CSR_TAIL_WRITE_THRESH) {
-		txq_write_tail(tmp_qp, queue);
-	}
+	txq_write_tail(tmp_qp, queue);
 	return nb_ops_sent;
 }
 
 uint16_t
 qat_dequeue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 {
-	struct qat_queue *rx_queue, *tx_queue;
+	struct qat_queue *rx_queue;
 	struct qat_qp *tmp_qp = (struct qat_qp *)qp;
 	uint32_t head;
 	uint32_t resp_counter = 0;
 	uint8_t *resp_msg;
 
 	rx_queue = &(tmp_qp->rx_q);
-	tx_queue = &(tmp_qp->tx_q);
 	head = rx_queue->head;
 	resp_msg = (uint8_t *)rx_queue->base_addr + rx_queue->head;
 
@@ -677,11 +671,7 @@ qat_dequeue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 						QAT_CSR_HEAD_WRITE_THRESH)
 			rxq_free_desc(tmp_qp, rx_queue);
 	}
-	/* also check if tail needs to be advanced */
-	if (tmp_qp->inflights16 <= QAT_CSR_TAIL_FORCE_WRITE_THRESH &&
-		tx_queue->tail != tx_queue->csr_tail) {
-		txq_write_tail(tmp_qp, tx_queue);
-	}
+
 	return resp_counter;
 }
 
diff --git a/drivers/common/qat/qat_qp.h b/drivers/common/qat/qat_qp.h
index 980c2ba32..9212ca457 100644
--- a/drivers/common/qat/qat_qp.h
+++ b/drivers/common/qat/qat_qp.h
@@ -11,10 +11,6 @@ struct qat_pci_device;
 
 #define QAT_CSR_HEAD_WRITE_THRESH 32U
 /* number of requests to accumulate before writing head CSR */
-#define QAT_CSR_TAIL_WRITE_THRESH 32U
-/* number of requests to accumulate before writing tail CSR */
-#define QAT_CSR_TAIL_FORCE_WRITE_THRESH 256U
-/* number of inflights below which no tail write coalescing should occur */
 
 typedef int (*build_request_t)(void *op,
 		uint8_t *req, void *op_cookie,
@@ -64,8 +60,6 @@ struct qat_queue {
 	uint32_t	csr_tail;		/* last written tail value */
 	uint16_t	nb_processed_responses;
 	/* number of responses processed since last CSR head write */
-	uint16_t	nb_pending_requests;
-	/* number of requests pending since last CSR tail write */
 };
 
 struct qat_qp {
-- 
2.13.6

[dpdk-dev] [PATCH v2 2/3] common/qat: move max inflights param into qp

[Fiona Trahe]

The max_inflights parameter is moved from qat_queue to qat_qp as it's
a more appropriate location.

Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
---
 drivers/common/qat/qat_qp.c | 23 ++++++++++++-----------
 drivers/common/qat/qat_qp.h |  2 +-
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/common/qat/qat_qp.c b/drivers/common/qat/qat_qp.c
index 01ddce008..8e4c74a02 100644
--- a/drivers/common/qat/qat_qp.c
+++ b/drivers/common/qat/qat_qp.c
@@ -239,6 +239,15 @@ int qat_qp_setup(struct qat_pci_device *qat_dev,
 		goto create_err;
 	}
 
+	qp->max_inflights = ADF_MAX_INFLIGHTS(qp->tx_q.queue_size,
+				ADF_BYTES_TO_MSG_SIZE(qp->tx_q.msg_size));
+
+	if (qp->max_inflights < 2) {
+		QAT_LOG(ERR, "Invalid num inflights");
+		qat_queue_delete(&(qp->tx_q));
+		goto create_err;
+	}
+
 	if (qat_queue_create(qat_dev, &(qp->rx_q), qat_qp_conf,
 					ADF_RING_DIR_RX) != 0) {
 		QAT_LOG(ERR, "Rx queue create failed "
@@ -416,15 +425,7 @@ qat_queue_create(struct qat_pci_device *qat_dev, struct qat_queue *queue,
 		goto queue_create_err;
 	}
 
-	queue->max_inflights = ADF_MAX_INFLIGHTS(queue->queue_size,
-					ADF_BYTES_TO_MSG_SIZE(desc_size));
 	queue->modulo_mask = (1 << ADF_RING_SIZE_MODULO(queue->queue_size)) - 1;
-
-	if (queue->max_inflights < 2) {
-		QAT_LOG(ERR, "Invalid num inflights");
-		ret = -EINVAL;
-		goto queue_create_err;
-	}
 	queue->head = 0;
 	queue->tail = 0;
 	queue->msg_size = desc_size;
@@ -443,11 +444,11 @@ qat_queue_create(struct qat_pci_device *qat_dev, struct qat_queue *queue,
 			queue->hw_queue_number, queue_base);
 
 	QAT_LOG(DEBUG, "RING: Name:%s, size in CSR: %u, in bytes %u,"
-		" nb msgs %u, msg_size %u, max_inflights %u modulo mask %u",
+		" nb msgs %u, msg_size %u, modulo mask %u",
 			queue->memz_name,
 			queue->queue_size, queue_size_bytes,
 			qp_conf->nb_descriptors, desc_size,
-			queue->max_inflights, queue->modulo_mask);
+			queue->modulo_mask);
 
 	return 0;
 
@@ -590,7 +591,7 @@ qat_enqueue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 
 	/* Find how many can actually fit on the ring */
 	tmp_qp->inflights16 += nb_ops;
-	overflow = tmp_qp->inflights16 - queue->max_inflights;
+	overflow = tmp_qp->inflights16 - tmp_qp->max_inflights;
 	if (overflow > 0) {
 		tmp_qp->inflights16 -= overflow;
 		nb_ops_possible = nb_ops - overflow;
diff --git a/drivers/common/qat/qat_qp.h b/drivers/common/qat/qat_qp.h
index 9212ca457..5066f06f0 100644
--- a/drivers/common/qat/qat_qp.h
+++ b/drivers/common/qat/qat_qp.h
@@ -51,7 +51,6 @@ struct qat_queue {
 	uint32_t	tail;			/* Shadow copy of the tail */
 	uint32_t	modulo_mask;
 	uint32_t	msg_size;
-	uint16_t	max_inflights;
 	uint32_t	queue_size;
 	uint8_t		hw_bundle_number;
 	uint8_t		hw_queue_number;
@@ -76,6 +75,7 @@ struct qat_qp {
 	enum qat_service_type service_type;
 	struct qat_pci_device *qat_dev;
 	/**< qat device this qp is on */
+	uint16_t max_inflights;
 } __rte_cache_aligned;
 
 extern const struct qat_qp_hw_data qat_gen1_qps[][ADF_MAX_QPS_ON_ANY_SERVICE];
-- 
2.13.6

[dpdk-dev] [PATCH v2 3/3] common/qat: add dual thread support

[Fiona Trahe]

Remove the limitation whereby enqueue and dequeue must be
done in same thread.
The inflight calculation is reworked to be thread-safe for 2
threads - note this is not general multi-thread support, i.e
all enqueues to a qp must still be done in one thread and
all dequeues must be done in one thread, but enqueues and
dequeues may be in separate threads.
Documentation updated.

Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
---
 doc/guides/compressdevs/qat_comp.rst |  5 ++++-
 doc/guides/cryptodevs/qat.rst        | 11 ++++++++--
 drivers/common/qat/qat_qp.c          | 40 +++++++++++++++++++++---------------
 drivers/common/qat/qat_qp.h          |  3 ++-
 4 files changed, 39 insertions(+), 20 deletions(-)

diff --git a/doc/guides/compressdevs/qat_comp.rst b/doc/guides/compressdevs/qat_comp.rst
index 6f583a460..669e288e3 100644
--- a/doc/guides/compressdevs/qat_comp.rst
+++ b/doc/guides/compressdevs/qat_comp.rst
@@ -33,7 +33,10 @@ Limitations
 -----------
 
 * Compressdev level 0, no compression, is not supported.
-* Queue pairs are not thread-safe (that is, within a single queue pair, RX and TX from different lcores is not supported).
+* QAT queue-pairs are thread-safe when process runs on an Intel CPU but QAT queues are not
+  (that is, within a single queue-pair all enqueues to the TX queue must be done from one
+  thread and all dequeues from the RX queue must be done from one thread, but enqueues
+  and dequeues may be done in different threads.)
 * No BSD support as BSD QAT kernel driver not available.
 * When using Deflate dynamic huffman encoding for compression, the input size (op.src.length)
   must be < CONFIG_RTE_PMD_QAT_COMP_IM_BUFFER_SIZE from the config file,
diff --git a/doc/guides/cryptodevs/qat.rst b/doc/guides/cryptodevs/qat.rst
index e905f6d00..750a03e6c 100644
--- a/doc/guides/cryptodevs/qat.rst
+++ b/doc/guides/cryptodevs/qat.rst
@@ -81,7 +81,11 @@ Limitations
 * No BSD support as BSD QAT kernel driver not available.
 * ZUC EEA3/EIA3 is not supported by dh895xcc devices
 * Maximum additional authenticated data (AAD) for GCM is 240 bytes long and must be passed to the device in a buffer rounded up to the nearest block-size multiple (x16) and padded with zeros.
-* Queue pairs are not thread-safe (that is, within a single queue pair, RX and TX from different lcores is not supported).
+* QAT queue-pairs are thread-safe when process runs on an Intel CPU but QAT queues are not
+  (that is, within a single queue-pair all enqueues to the TX queue must be done from one
+  thread and all dequeues from the RX queue must be done from one thread, but enqueues
+  and dequeues may be done in different threads.)
+
 
 Extra notes on KASUMI F9
 ~~~~~~~~~~~~~~~~~~~~~~~~
@@ -122,7 +126,10 @@ Limitations
 ~~~~~~~~~~~
 
 * Big integers longer than 4096 bits are not supported.
-* Queue pairs are not thread-safe (that is, within a single queue pair, RX and TX from different lcores is not supported).
+* QAT queue-pairs are thread-safe when process runs on an Intel CPU but QAT queues are not
+  (that is, within a single queue-pair all enqueues to the TX queue must be done from one
+  thread and all dequeues from the RX queue must be done from one thread, but enqueues
+  and dequeues may be done in different threads.)
 
 .. _building_qat:
 
diff --git a/drivers/common/qat/qat_qp.c b/drivers/common/qat/qat_qp.c
index 8e4c74a02..30cdc618d 100644
--- a/drivers/common/qat/qat_qp.c
+++ b/drivers/common/qat/qat_qp.c
@@ -230,7 +230,7 @@ int qat_qp_setup(struct qat_pci_device *qat_dev,
 	}
 
 	qp->mmap_bar_addr = pci_dev->mem_resource[0].addr;
-	qp->inflights16 = 0;
+	qp->enqueued = qp->dequeued = 0;
 
 	if (qat_queue_create(qat_dev, &(qp->tx_q), qat_qp_conf,
 					ADF_RING_DIR_TX) != 0) {
@@ -321,7 +321,7 @@ int qat_qp_release(struct qat_qp **qp_addr)
 				qp->qat_dev->qat_dev_id);
 
 	/* Don't free memory if there are still responses to be processed */
-	if (qp->inflights16 == 0) {
+	if ((qp->enqueued - qp->dequeued) == 0) {
 		qat_queue_delete(&(qp->tx_q));
 		qat_queue_delete(&(qp->rx_q));
 	} else {
@@ -579,7 +579,6 @@ qat_enqueue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 	uint16_t nb_ops_possible = nb_ops;
 	register uint8_t *base_addr;
 	register uint32_t tail;
-	int overflow;
 
 	if (unlikely(nb_ops == 0))
 		return 0;
@@ -590,13 +589,25 @@ qat_enqueue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 	tail = queue->tail;
 
 	/* Find how many can actually fit on the ring */
-	tmp_qp->inflights16 += nb_ops;
-	overflow = tmp_qp->inflights16 - tmp_qp->max_inflights;
-	if (overflow > 0) {
-		tmp_qp->inflights16 -= overflow;
-		nb_ops_possible = nb_ops - overflow;
-		if (nb_ops_possible == 0)
-			return 0;
+	{
+		/* dequeued can only be written by one thread, but it may not
+		 * be this thread. As it's 4-byte aligned it will be read
+		 * atomically here by any Intel CPU.
+		 * enqueued can wrap before dequeued, but cannot
+		 * lap it as var size of enq/deq (uint32_t) > var size of
+		 * max_inflights (uint16_t). In reality inflights is never
+		 * even as big as max uint16_t, as it's <= ADF_MAX_DESC.
+		 * On wrapping, the calculation still returns the correct
+		 * positive value as all three vars are unsigned.
+		 */
+		uint32_t inflights =
+			tmp_qp->enqueued - tmp_qp->dequeued;
+
+		if ((inflights + nb_ops) > tmp_qp->max_inflights) {
+			nb_ops_possible = tmp_qp->max_inflights - inflights;
+			if (nb_ops_possible == 0)
+				return 0;
+		}
 	}
 
 	while (nb_ops_sent != nb_ops_possible) {
@@ -605,11 +616,7 @@ qat_enqueue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 				tmp_qp->qat_dev_gen);
 		if (ret != 0) {
 			tmp_qp->stats.enqueue_err_count++;
-			/*
-			 * This message cannot be enqueued,
-			 * decrease number of ops that wasn't sent
-			 */
-			tmp_qp->inflights16 -= nb_ops_possible - nb_ops_sent;
+			/* This message cannot be enqueued */
 			if (nb_ops_sent == 0)
 				return 0;
 			goto kick_tail;
@@ -621,6 +628,7 @@ qat_enqueue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 	}
 kick_tail:
 	queue->tail = tail;
+	tmp_qp->enqueued += nb_ops_sent;
 	tmp_qp->stats.enqueued_count += nb_ops_sent;
 	txq_write_tail(tmp_qp, queue);
 	return nb_ops_sent;
@@ -664,9 +672,9 @@ qat_dequeue_op_burst(void *qp, void **ops, uint16_t nb_ops)
 	}
 	if (resp_counter > 0) {
 		rx_queue->head = head;
+		tmp_qp->dequeued += resp_counter;
 		tmp_qp->stats.dequeued_count += resp_counter;
 		rx_queue->nb_processed_responses += resp_counter;
-		tmp_qp->inflights16 -= resp_counter;
 
 		if (rx_queue->nb_processed_responses >
 						QAT_CSR_HEAD_WRITE_THRESH)
diff --git a/drivers/common/qat/qat_qp.h b/drivers/common/qat/qat_qp.h
index 5066f06f0..8b9ab79ff 100644
--- a/drivers/common/qat/qat_qp.h
+++ b/drivers/common/qat/qat_qp.h
@@ -63,7 +63,6 @@ struct qat_queue {
 
 struct qat_qp {
 	void			*mmap_bar_addr;
-	uint16_t		inflights16;
 	struct qat_queue	tx_q;
 	struct qat_queue	rx_q;
 	struct qat_common_stats stats;
@@ -75,6 +74,8 @@ struct qat_qp {
 	enum qat_service_type service_type;
 	struct qat_pci_device *qat_dev;
 	/**< qat device this qp is on */
+	uint32_t enqueued;
+	uint32_t dequeued __rte_aligned(4);
 	uint16_t max_inflights;
 } __rte_cache_aligned;
 
-- 
2.13.6

Re: [dpdk-dev] [PATCH v2 0/3] Add dual threading in QAT PMD

[Akhil Goyal]

Hi Fiona,

This patchset need a rebase. Could you please send v3.

Thanks,
Akhil

> -----Original Message-----
> From: Fiona Trahe <fiona.trahe@intel.com>
> Sent: Friday, September 6, 2019 9:42 PM
> To: dev@dpdk.org
> Cc: Akhil Goyal <akhil.goyal@nxp.com>; arkadiuszx.kusztal@intel.com;
> fiona.trahe@intel.com
> Subject: [PATCH v2 0/3] Add dual threading in QAT PMD
> 
> Remove the limitation whereby enqueue and dequeue must be
> done in same thread.
> The inflight calculation is reworked to be thread-safe for 2
> threads - note this is not general multi-thread support, i.e
> all enqueues to a qp must still be done in one thread and
> all dequeues must be done in one thread, but enqueues and
> dequeues may be in separate threads.
> As the tail-coalescing feature is not
> threadsafe it is removed first.
> 
> v2 changes:
>  - clarified wording in docs
> 
> Fiona Trahe (3):
>   common/qat: remove tail write coalescing feature
>   common/qat: move max inflights param into qp
>   common/qat: add dual thread support
> 
>  doc/guides/compressdevs/qat_comp.rst |  5 ++-
>  doc/guides/cryptodevs/qat.rst        | 11 +++++-
>  drivers/common/qat/qat_qp.c          | 77 ++++++++++++++++++------------------
>  drivers/common/qat/qat_qp.h          | 11 ++----
>  4 files changed, 54 insertions(+), 50 deletions(-)
> 
> --
> 2.13.6

Re: [dpdk-dev] [PATCH v2 0/3] Add dual threading in QAT PMD

[Trahe, Fiona]

Hi Akhil,
We're going to defer this patchset this to 20.02. 
We want to add another patch to it to mitigate some performance impacts it causes.#
I'm not sure of the process for this - do I just mark it in patchwork as deferred?
Or is there a tag I can put in an email, like Deferred-by?
Fiona

> -----Original Message-----
> From: Akhil Goyal [mailto:akhil.goyal@nxp.com]
> Sent: Friday, October 4, 2019 11:48 AM
> To: Trahe, Fiona <fiona.trahe@intel.com>; dev@dpdk.org
> Cc: Kusztal, ArkadiuszX <arkadiuszx.kusztal@intel.com>
> Subject: RE: [PATCH v2 0/3] Add dual threading in QAT PMD
> 
> Hi Fiona,
> 
> This patchset need a rebase. Could you please send v3.
> 
> Thanks,
> Akhil
> 
> > -----Original Message-----
> > From: Fiona Trahe <fiona.trahe@intel.com>
> > Sent: Friday, September 6, 2019 9:42 PM
> > To: dev@dpdk.org
> > Cc: Akhil Goyal <akhil.goyal@nxp.com>; arkadiuszx.kusztal@intel.com;
> > fiona.trahe@intel.com
> > Subject: [PATCH v2 0/3] Add dual threading in QAT PMD
> >
> > Remove the limitation whereby enqueue and dequeue must be
> > done in same thread.
> > The inflight calculation is reworked to be thread-safe for 2
> > threads - note this is not general multi-thread support, i.e
> > all enqueues to a qp must still be done in one thread and
> > all dequeues must be done in one thread, but enqueues and
> > dequeues may be in separate threads.
> > As the tail-coalescing feature is not
> > threadsafe it is removed first.
> >
> > v2 changes:
> >  - clarified wording in docs
> >
> > Fiona Trahe (3):
> >   common/qat: remove tail write coalescing feature
> >   common/qat: move max inflights param into qp
> >   common/qat: add dual thread support
> >
> >  doc/guides/compressdevs/qat_comp.rst |  5 ++-
> >  doc/guides/cryptodevs/qat.rst        | 11 +++++-
> >  drivers/common/qat/qat_qp.c          | 77 ++++++++++++++++++------------------
> >  drivers/common/qat/qat_qp.h          | 11 ++----
> >  4 files changed, 54 insertions(+), 50 deletions(-)
> >
> > --
> > 2.13.6