crypto/qat: remove atomics

Replacing atomics in the QAT driver with simple 16-bit integers for
number of inflight packets.

This adds a new limitation to the QAT driver: each queue pair is
now explicitly single-threaded.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Fiona Trahe <fiona.trahe@intel.com>

diff --git a/doc/guides/cryptodevs/qat.rst b/doc/guides/cryptodevs/qat.rst
index a3fce7b..cb17b6b 100644 (file)
--- a/doc/guides/cryptodevs/qat.rst
+++ b/doc/guides/cryptodevs/qat.rst
@@ -90,6 +90,7 @@ 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.
+* Queue pairs are not thread-safe (that is, within a single queue pair, RX and TX from different lcores is not supported).
 
 
 Installation

diff --git a/doc/guides/rel_notes/release_17_11.rst b/doc/guides/rel_notes/release_17_11.rst
index 585110f..5bbc3f2 100644 (file)
--- a/doc/guides/rel_notes/release_17_11.rst
+++ b/doc/guides/rel_notes/release_17_11.rst
@@ -81,6 +81,12 @@ New Features
    * Support for Flow API
    * Support for Tx and Rx descriptor status functions
 
+* **Updated QAT crypto PMD.**
+
+  Performance enhancements:
+
+  * Removed atomics from the internal queue pair structure.
+
 * **Added IOMMU support to libvhost-user**
 
   Implemented device IOTLB in Vhost-user backend, and enabled Virtio's IOMMU

diff --git a/drivers/crypto/qat/qat_crypto.c b/drivers/crypto/qat/qat_crypto.c
index 62ee175..bb199ae 100644 (file)
--- a/drivers/crypto/qat/qat_crypto.c
+++ b/drivers/crypto/qat/qat_crypto.c
@@ -51,7 +51,6 @@
 #include <rte_eal.h>
 #include <rte_per_lcore.h>
 #include <rte_lcore.h>
-#include <rte_atomic.h>
 #include <rte_branch_prediction.h>
 #include <rte_mempool.h>
 #include <rte_mbuf.h>
@@ -945,10 +944,10 @@ qat_pmd_enqueue_op_burst(void *qp, struct rte_crypto_op **ops,
        tail = queue->tail;
 
        /* Find how many can actually fit on the ring */
-       overflow = rte_atomic16_add_return(&tmp_qp->inflights16, nb_ops)
-                               - queue->max_inflights;
+       tmp_qp->inflights16 += nb_ops;
+       overflow = tmp_qp->inflights16 - queue->max_inflights;
        if (overflow > 0) {
-               rte_atomic16_sub(&tmp_qp->inflights16, overflow);
+               tmp_qp->inflights16 -= overflow;
                nb_ops_possible = nb_ops - overflow;
                if (nb_ops_possible == 0)
                        return 0;
@@ -963,8 +962,7 @@ qat_pmd_enqueue_op_burst(void *qp, struct rte_crypto_op **ops,
                         * This message cannot be enqueued,
                         * decrease number of ops that wasn't sent
                         */
-                       rte_atomic16_sub(&tmp_qp->inflights16,
-                                       nb_ops_possible - nb_ops_sent);
+                       tmp_qp->inflights16 -= nb_ops_possible - nb_ops_sent;
                        if (nb_ops_sent == 0)
                                return 0;
                        goto kick_tail;
@@ -1036,7 +1034,7 @@ qat_pmd_dequeue_op_burst(void *qp, struct rte_crypto_op **ops,
                WRITE_CSR_RING_HEAD(tmp_qp->mmap_bar_addr,
                                        queue->hw_bundle_number,
                                        queue->hw_queue_number, queue->head);
-               rte_atomic16_sub(&tmp_qp->inflights16, msg_counter);
+               tmp_qp->inflights16 -= msg_counter;
                tmp_qp->stats.dequeued_count += msg_counter;
        }
        return msg_counter;

diff --git a/drivers/crypto/qat/qat_crypto.h b/drivers/crypto/qat/qat_crypto.h
index 3f35a00..7773b57 100644 (file)
--- a/drivers/crypto/qat/qat_crypto.h
+++ b/drivers/crypto/qat/qat_crypto.h
@@ -77,7 +77,7 @@ struct qat_queue {
 
 struct qat_qp {
        void                    *mmap_bar_addr;
-       rte_atomic16_t          inflights16;
+       uint16_t                inflights16;
        struct  qat_queue       tx_q;
        struct  qat_queue       rx_q;
        struct  rte_cryptodev_stats stats;

diff --git a/drivers/crypto/qat/qat_qp.c b/drivers/crypto/qat/qat_qp.c
index 34f75ca..8bd60ff 100644 (file)
--- a/drivers/crypto/qat/qat_qp.c
+++ b/drivers/crypto/qat/qat_qp.c
@@ -181,7 +181,7 @@ int qat_crypto_sym_qp_setup(struct rte_cryptodev *dev, uint16_t queue_pair_id,
                        RTE_CACHE_LINE_SIZE);
 
        qp->mmap_bar_addr = pci_dev->mem_resource[0].addr;
-       rte_atomic16_init(&qp->inflights16);
+       qp->inflights16 = 0;
 
        if (qat_tx_queue_create(dev, &(qp->tx_q),
                queue_pair_id, qp_conf->nb_descriptors, socket_id) != 0) {
@@ -264,7 +264,7 @@ int qat_crypto_sym_qp_release(struct rte_cryptodev *dev, uint16_t queue_pair_id)
        }
 
        /* Don't free memory if there are still responses to be processed */
-       if (rte_atomic16_read(&(qp->inflights16)) == 0) {
+       if (qp->inflights16 == 0) {
                qat_queue_delete(&(qp->tx_q));
                qat_queue_delete(&(qp->rx_q));
        } else {