From 5e1d11ecf5212153ffb095d4a49fbc38d9112624 Mon Sep 17 00:00:00 2001 From: Nelio Laranjeiro Date: Thu, 3 Mar 2016 15:27:11 +0100 Subject: [PATCH] mlx5: prefetch next Tx mbuf header and data This change improves performance noticeably. Signed-off-by: Nelio Laranjeiro --- drivers/net/mlx5/mlx5_rxtx.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c index 75855707d0..bee5ce2c8d 100644 --- a/drivers/net/mlx5/mlx5_rxtx.c +++ b/drivers/net/mlx5/mlx5_rxtx.c @@ -443,8 +443,11 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) unsigned int i; unsigned int max; int err; + struct rte_mbuf *buf = pkts[0]; assert(elts_comp_cd != 0); + /* Prefetch first packet cacheline. */ + rte_prefetch0(buf); txq_complete(txq); max = (elts_n - (elts_head - txq->elts_tail)); if (max > elts_n) @@ -458,7 +461,7 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) if (max > pkts_n) max = pkts_n; for (i = 0; (i != max); ++i) { - struct rte_mbuf *buf = pkts[i]; + struct rte_mbuf *buf_next = pkts[i + 1]; unsigned int elts_head_next = (((elts_head + 1) == elts_n) ? 0 : elts_head + 1); struct txq_elt *elt_next = &(*txq->elts)[elts_head_next]; @@ -481,6 +484,8 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) tmp = next; } while (tmp != NULL); } + if (i + 1 < max) + rte_prefetch0(buf_next); /* Request TX completion. */ if (unlikely(--elts_comp_cd == 0)) { elts_comp_cd = txq->elts_comp_cd_init; @@ -502,6 +507,7 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) uintptr_t addr; uint32_t length; uint32_t lkey; + uintptr_t buf_next_addr; /* Retrieve buffer information. */ addr = rte_pktmbuf_mtod(buf, uintptr_t); @@ -522,6 +528,13 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) rte_prefetch0((volatile void *) (uintptr_t)addr); RTE_MBUF_PREFETCH_TO_FREE(elt_next->buf); + /* Prefetch next buffer data. */ + if (i + 1 < max) { + buf_next_addr = + rte_pktmbuf_mtod(buf_next, uintptr_t); + rte_prefetch0((volatile void *) + (uintptr_t)buf_next_addr); + } /* Put packet into send queue. */ #if MLX5_PMD_MAX_INLINE > 0 if (length <= txq->max_inline) @@ -571,6 +584,7 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) #endif /* MLX5_PMD_SGE_WR_N > 1 */ } elts_head = elts_head_next; + buf = buf_next; #ifdef MLX5_PMD_SOFT_COUNTERS /* Increment sent bytes counter. */ txq->stats.obytes += sent_size; -- 2.20.1