[dpdk-dev] [PATCH 2/6] net/mlx5: reduce Tx and Rx structure size

Nelio Laranjeiro nelio.laranjeiro at 6wind.com
Wed Sep 7 09:09:55 CEST 2016


PMD uses only power of two number of descriptors, storing the number of
elements in log2 helps to reduce the size of the container to store it.

Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro at 6wind.com>
Signed-off-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>
---
 drivers/net/mlx5/mlx5_ethdev.c |  4 ++--
 drivers/net/mlx5/mlx5_rxq.c    | 10 +++++-----
 drivers/net/mlx5/mlx5_rxtx.c   | 10 +++++-----
 drivers/net/mlx5/mlx5_rxtx.h   | 12 +++++++-----
 drivers/net/mlx5/mlx5_txq.c    |  6 +++---
 5 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
index 1ae80e5..137ea66 100644
--- a/drivers/net/mlx5/mlx5_ethdev.c
+++ b/drivers/net/mlx5/mlx5_ethdev.c
@@ -808,7 +808,7 @@ recover:
 		if (rehash)
 			ret = rxq_rehash(dev, rxq_ctrl);
 		else
-			ret = rxq_ctrl_setup(dev, rxq_ctrl, rxq->elts_n,
+			ret = rxq_ctrl_setup(dev, rxq_ctrl, 1 << rxq->elts_n,
 					     rxq_ctrl->socket, NULL, rxq->mp);
 		if (!ret)
 			continue;
@@ -1314,7 +1314,7 @@ mlx5_secondary_data_setup(struct priv *priv)
 		if (txq_ctrl != NULL) {
 			if (txq_ctrl_setup(priv->dev,
 					   primary_txq_ctrl,
-					   primary_txq->elts_n,
+					   1 << primary_txq->elts_n,
 					   primary_txq_ctrl->socket,
 					   NULL) == 0) {
 				txq_ctrl->txq.stats.idx =
diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index 44889d1..d9db368 100644
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -723,7 +723,7 @@ rxq_free_elts(struct rxq_ctrl *rxq_ctrl)
 	if (rxq_ctrl->rxq.elts == NULL)
 		return;
 
-	for (i = 0; (i != rxq_ctrl->rxq.elts_n); ++i) {
+	for (i = 0; (i != (1u << rxq_ctrl->rxq.elts_n)); ++i) {
 		if ((*rxq_ctrl->rxq.elts)[i] != NULL)
 			rte_pktmbuf_free_seg((*rxq_ctrl->rxq.elts)[i]);
 		(*rxq_ctrl->rxq.elts)[i] = NULL;
@@ -807,7 +807,7 @@ rxq_cleanup(struct rxq_ctrl *rxq_ctrl)
 int
 rxq_rehash(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl)
 {
-	unsigned int elts_n = rxq_ctrl->rxq.elts_n;
+	unsigned int elts_n = 1 << rxq_ctrl->rxq.elts_n;
 	unsigned int i;
 	struct ibv_exp_wq_attr mod;
 	int err;
@@ -870,7 +870,7 @@ rxq_setup(struct rxq_ctrl *tmpl)
 	struct ibv_cq *ibcq = tmpl->cq;
 	struct mlx5_cq *cq = to_mxxx(cq, cq);
 	struct mlx5_rwq *rwq = container_of(tmpl->wq, struct mlx5_rwq, wq);
-	struct rte_mbuf *(*elts)[tmpl->rxq.elts_n] =
+	struct rte_mbuf *(*elts)[1 << tmpl->rxq.elts_n] =
 		rte_calloc_socket("RXQ", 1, sizeof(*elts), 0, tmpl->socket);
 
 	if (cq->cqe_sz != RTE_CACHE_LINE_SIZE) {
@@ -924,7 +924,7 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl,
 		.priv = priv,
 		.socket = socket,
 		.rxq = {
-			.elts_n = desc,
+			.elts_n = log2above(desc),
 			.mp = mp,
 		},
 	};
@@ -1148,7 +1148,7 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl,
 	}
 	/* Reuse buffers from original queue if possible. */
 	if (rxq_ctrl->rxq.elts_n) {
-		assert(rxq_ctrl->rxq.elts_n == desc);
+		assert(1 << rxq_ctrl->rxq.elts_n == desc);
 		assert(rxq_ctrl->rxq.elts != tmpl.rxq.elts);
 		ret = rxq_alloc_elts(&tmpl, desc, rxq_ctrl->rxq.elts);
 	} else
diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index 5feeb3f..e132727 100644
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -166,8 +166,8 @@ txq_complete(struct txq *txq) __attribute__((always_inline));
 static inline void
 txq_complete(struct txq *txq)
 {
-	const unsigned int elts_n = txq->elts_n;
 	const unsigned int cqe_n = txq->cqe_n;
+	const unsigned int elts_n = 1 << txq->elts_n;
 	const unsigned int cqe_cnt = cqe_n - 1;
 	uint16_t elts_free = txq->elts_tail;
 	uint16_t elts_tail;
@@ -468,7 +468,7 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
 {
 	struct txq *txq = (struct txq *)dpdk_txq;
 	uint16_t elts_head = txq->elts_head;
-	const unsigned int elts_n = txq->elts_n;
+	const unsigned int elts_n = 1 << txq->elts_n;
 	unsigned int i = 0;
 	unsigned int j = 0;
 	unsigned int max;
@@ -680,7 +680,7 @@ mlx5_tx_burst_mpw(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
 {
 	struct txq *txq = (struct txq *)dpdk_txq;
 	uint16_t elts_head = txq->elts_head;
-	const unsigned int elts_n = txq->elts_n;
+	const unsigned int elts_n = 1 << txq->elts_n;
 	unsigned int i = 0;
 	unsigned int j = 0;
 	unsigned int max;
@@ -884,7 +884,7 @@ mlx5_tx_burst_mpw_inline(void *dpdk_txq, struct rte_mbuf **pkts,
 {
 	struct txq *txq = (struct txq *)dpdk_txq;
 	uint16_t elts_head = txq->elts_head;
-	const unsigned int elts_n = txq->elts_n;
+	const unsigned int elts_n = 1 << txq->elts_n;
 	unsigned int i = 0;
 	unsigned int j = 0;
 	unsigned int max;
@@ -1272,8 +1272,8 @@ uint16_t
 mlx5_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
 {
 	struct rxq *rxq = dpdk_rxq;
-	const unsigned int wqe_cnt = rxq->elts_n - 1;
 	const unsigned int cqe_cnt = rxq->cqe_n - 1;
+	const unsigned int wqe_cnt = (1 << rxq->elts_n) - 1;
 	const unsigned int sges_n = rxq->sges_n;
 	struct rte_mbuf *pkt = NULL;
 	struct rte_mbuf *seg = NULL;
diff --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h
index fbc2a78..3ba3913 100644
--- a/drivers/net/mlx5/mlx5_rxtx.h
+++ b/drivers/net/mlx5/mlx5_rxtx.h
@@ -54,6 +54,7 @@
 #endif
 #include <rte_mbuf.h>
 #include <rte_mempool.h>
+#include <rte_common.h>
 #ifdef PEDANTIC
 #pragma GCC diagnostic error "-pedantic"
 #endif
@@ -109,16 +110,16 @@ struct rxq {
 	unsigned int vlan_strip:1; /* Enable VLAN stripping. */
 	unsigned int crc_present:1; /* CRC must be subtracted. */
 	unsigned int sges_n:2; /* Log 2 of SGEs (max buffers per packet). */
+	unsigned int elts_n:4; /* Log 2 of Mbufs. */
+	unsigned int port_id:8;
+	volatile uint32_t *rq_db;
+	volatile uint32_t *cq_db;
 	uint16_t rq_ci;
 	uint16_t cq_ci;
-	uint16_t elts_n;
 	uint16_t cqe_n; /* Number of CQ elements. */
-	uint16_t port_id;
 	volatile struct mlx5_wqe_data_seg(*wqes)[];
 	volatile struct mlx5_cqe(*cqes)[];
 	struct rxq_zip zip; /* Compressed context. */
-	volatile uint32_t *rq_db;
-	volatile uint32_t *cq_db;
 	struct rte_mbuf *(*elts)[];
 	struct rte_mempool *mp;
 	struct mlx5_rxq_stats stats;
@@ -238,15 +239,16 @@ struct hash_rxq {
 };
 
 /* TX queue descriptor. */
+RTE_STD_C11
 struct txq {
 	uint16_t elts_head; /* Current index in (*elts)[]. */
 	uint16_t elts_tail; /* First element awaiting completion. */
 	uint16_t elts_comp; /* Counter since last completion request. */
-	uint16_t elts_n; /* (*elts)[] length. */
 	uint16_t cq_ci; /* Consumer index for completion queue. */
 	uint16_t cqe_n; /* Number of CQ elements. */
 	uint16_t wqe_ci; /* Consumer index for work queue. */
 	uint16_t wqe_n; /* Number of WQ elements. */
+	uint16_t elts_n:4; /* (*elts)[] length (in log2). */
 	uint16_t bf_offset; /* Blueflame offset. */
 	uint16_t bf_buf_size; /* Blueflame size. */
 	uint16_t max_inline; /* Multiple of RTE_CACHE_LINE_SIZE to inline. */
diff --git a/drivers/net/mlx5/mlx5_txq.c b/drivers/net/mlx5/mlx5_txq.c
index e8ebbbe..9055016 100644
--- a/drivers/net/mlx5/mlx5_txq.c
+++ b/drivers/net/mlx5/mlx5_txq.c
@@ -101,7 +101,7 @@ txq_alloc_elts(struct txq_ctrl *txq_ctrl, unsigned int elts_n)
 static void
 txq_free_elts(struct txq_ctrl *txq_ctrl)
 {
-	unsigned int elts_n = txq_ctrl->txq.elts_n;
+	unsigned int elts_n = 1 << txq_ctrl->txq.elts_n;
 	unsigned int elts_head = txq_ctrl->txq.elts_head;
 	unsigned int elts_tail = txq_ctrl->txq.elts_tail;
 	struct rte_mbuf *(*elts)[elts_n] = txq_ctrl->txq.elts;
@@ -227,7 +227,7 @@ txq_setup(struct txq_ctrl *tmpl, struct txq_ctrl *txq_ctrl)
 		(volatile struct mlx5_cqe (*)[])
 		(uintptr_t)cq->active_buf->buf;
 	tmpl->txq.elts =
-		(struct rte_mbuf *(*)[tmpl->txq.elts_n])
+		(struct rte_mbuf *(*)[1 << tmpl->txq.elts_n])
 		((uintptr_t)txq_ctrl + sizeof(*txq_ctrl));
 	return 0;
 }
@@ -277,7 +277,7 @@ txq_ctrl_setup(struct rte_eth_dev *dev, struct txq_ctrl *txq_ctrl,
 	}
 	(void)conf; /* Thresholds configuration (ignored). */
 	assert(desc > MLX5_TX_COMP_THRESH);
-	tmpl.txq.elts_n = desc;
+	tmpl.txq.elts_n = log2above(desc);
 	/* MRs will be registered in mp2mr[] later. */
 	attr.rd = (struct ibv_exp_res_domain_init_attr){
 		.comp_mask = (IBV_EXP_RES_DOMAIN_THREAD_MODEL |
-- 
2.1.4



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