From 50163aec51eb39e683a4b3a34aafef94ea54b772 Mon Sep 17 00:00:00 2001 From: Matan Azrad Date: Wed, 6 Dec 2017 17:57:55 +0000 Subject: [PATCH] net/mlx4: align Tx descriptors number Using power of 2 descriptors number makes the ring management easier and allows to use mask operation instead of wraparound conditions. Adjust Tx descriptor number to be power of 2 and change calculation to use mask accordingly. Signed-off-by: Matan Azrad Acked-by: Adrien Mazarguil --- drivers/net/mlx4/mlx4_rxtx.c | 28 +++++++++++++--------------- drivers/net/mlx4/mlx4_txq.c | 13 +++++++++---- 2 files changed, 22 insertions(+), 19 deletions(-) diff --git a/drivers/net/mlx4/mlx4_rxtx.c b/drivers/net/mlx4/mlx4_rxtx.c index 71ed3a9d14..d53e607c4e 100644 --- a/drivers/net/mlx4/mlx4_rxtx.c +++ b/drivers/net/mlx4/mlx4_rxtx.c @@ -312,10 +312,14 @@ mlx4_txq_stamp_freed_wqe(struct mlx4_sq *sq, volatile uint32_t *start, * * @param txq * Pointer to Tx queue structure. + * @param elts_m + * Tx elements number mask. + * @param sq + * Pointer to the SQ structure. */ static void -mlx4_txq_complete(struct txq *txq, const unsigned int elts_n, - struct mlx4_sq *sq) +mlx4_txq_complete(struct txq *txq, const unsigned int elts_m, + struct mlx4_sq *sq) { unsigned int elts_tail = txq->elts_tail; struct mlx4_cq *cq = &txq->mcq; @@ -355,13 +359,11 @@ mlx4_txq_complete(struct txq *txq, const unsigned int elts_n, if (unlikely(!completed)) return; /* First stamping address is the end of the last one. */ - first_txbb = (&(*txq->elts)[elts_tail])->eocb; + first_txbb = (&(*txq->elts)[elts_tail & elts_m])->eocb; elts_tail += completed; - if (elts_tail >= elts_n) - elts_tail -= elts_n; /* The new tail element holds the end address. */ sq->remain_size += mlx4_txq_stamp_freed_wqe(sq, first_txbb, - (&(*txq->elts)[elts_tail])->eocb); + (&(*txq->elts)[elts_tail & elts_m])->eocb); /* Update CQ consumer index. */ cq->cons_index = cons_index; *cq->set_ci_db = rte_cpu_to_be_32(cons_index & MLX4_CQ_DB_CI_MASK); @@ -580,6 +582,7 @@ mlx4_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) struct txq *txq = (struct txq *)dpdk_txq; unsigned int elts_head = txq->elts_head; const unsigned int elts_n = txq->elts_n; + const unsigned int elts_m = elts_n - 1; unsigned int bytes_sent = 0; unsigned int i; unsigned int max; @@ -589,24 +592,20 @@ mlx4_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) assert(txq->elts_comp_cd != 0); if (likely(txq->elts_comp != 0)) - mlx4_txq_complete(txq, elts_n, sq); + mlx4_txq_complete(txq, elts_m, sq); max = (elts_n - (elts_head - txq->elts_tail)); - if (max > elts_n) - max -= elts_n; assert(max >= 1); assert(max <= elts_n); /* Always leave one free entry in the ring. */ --max; if (max > pkts_n) max = pkts_n; - elt = &(*txq->elts)[elts_head]; + elt = &(*txq->elts)[elts_head & elts_m]; /* First Tx burst element saves the next WQE control segment. */ ctrl = elt->wqe; for (i = 0; (i != max); ++i) { struct rte_mbuf *buf = pkts[i]; - unsigned int elts_head_next = - (((elts_head + 1) == elts_n) ? 0 : elts_head + 1); - struct txq_elt *elt_next = &(*txq->elts)[elts_head_next]; + struct txq_elt *elt_next = &(*txq->elts)[++elts_head & elts_m]; uint32_t owner_opcode = sq->owner_opcode; volatile struct mlx4_wqe_data_seg *dseg = (volatile struct mlx4_wqe_data_seg *)(ctrl + 1); @@ -725,7 +724,6 @@ mlx4_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) ctrl->owner_opcode = rte_cpu_to_be_32(owner_opcode); elt->buf = buf; bytes_sent += buf->pkt_len; - elts_head = elts_head_next; ctrl = ctrl_next; elt = elt_next; } @@ -741,7 +739,7 @@ mlx4_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) rte_wmb(); /* Ring QP doorbell. */ rte_write32(txq->msq.doorbell_qpn, txq->msq.db); - txq->elts_head = elts_head; + txq->elts_head += i; txq->elts_comp += i; return i; } diff --git a/drivers/net/mlx4/mlx4_txq.c b/drivers/net/mlx4/mlx4_txq.c index 9d9bd246eb..c5048dbf07 100644 --- a/drivers/net/mlx4/mlx4_txq.c +++ b/drivers/net/mlx4/mlx4_txq.c @@ -75,17 +75,16 @@ mlx4_txq_free_elts(struct txq *txq) unsigned int elts_head = txq->elts_head; unsigned int elts_tail = txq->elts_tail; struct txq_elt (*elts)[txq->elts_n] = txq->elts; + unsigned int elts_m = txq->elts_n - 1; DEBUG("%p: freeing WRs", (void *)txq); while (elts_tail != elts_head) { - struct txq_elt *elt = &(*elts)[elts_tail]; + struct txq_elt *elt = &(*elts)[elts_tail++ & elts_m]; assert(elt->buf != NULL); rte_pktmbuf_free(elt->buf); elt->buf = NULL; elt->wqe = NULL; - if (++elts_tail == RTE_DIM(*elts)) - elts_tail = 0; } txq->elts_tail = txq->elts_head; } @@ -207,7 +206,7 @@ mlx4_tx_queue_setup(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc, struct mlx4dv_obj mlxdv; struct mlx4dv_qp dv_qp; struct mlx4dv_cq dv_cq; - struct txq_elt (*elts)[desc]; + struct txq_elt (*elts)[rte_align32pow2(desc)]; struct ibv_qp_init_attr qp_init_attr; struct txq *txq; uint8_t *bounce_buf; @@ -251,6 +250,12 @@ mlx4_tx_queue_setup(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc, ERROR("%p: invalid number of Tx descriptors", (void *)dev); return -rte_errno; } + if (desc != RTE_DIM(*elts)) { + desc = RTE_DIM(*elts); + WARN("%p: increased number of descriptors in Tx queue %u" + " to the next power of two (%u)", + (void *)dev, idx, desc); + } /* Allocate and initialize Tx queue. */ mlx4_zmallocv_socket("TXQ", vec, RTE_DIM(vec), socket); if (!txq) { -- 2.20.1