From: Nélio Laranjeiro Date: Thu, 24 Nov 2016 16:03:36 +0000 (+0100) Subject: net/mlx5: remove inefficient prefetching X-Git-Tag: spdx-start~4869 X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=0f3f22298e0ee837f575eb618d69033691c7aee2;p=dpdk.git net/mlx5: remove inefficient prefetching Prefetching completion queue entries is inefficient because too few CPU cycles are spent before their use, which results into cache misses anyway. Signed-off-by: Nelio Laranjeiro Acked-by: Adrien Mazarguil --- diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c index 380d137271..9820f727b4 100644 --- a/drivers/net/mlx5/mlx5_rxtx.c +++ b/drivers/net/mlx5/mlx5_rxtx.c @@ -345,23 +345,6 @@ mlx5_tx_dbrec(struct txq *txq) txq->bf_offset ^= (1 << txq->bf_buf_size); } -/** - * Prefetch a CQE. - * - * @param txq - * Pointer to TX queue structure. - * @param cqe_ci - * CQE consumer index. - */ -static inline void -tx_prefetch_cqe(struct txq *txq, uint16_t ci) -{ - volatile struct mlx5_cqe *cqe; - - cqe = &(*txq->cqes)[ci & ((1 << txq->cqe_n) - 1)]; - rte_prefetch0(cqe); -} - /** * DPDK callback for TX. * @@ -393,8 +376,6 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) if (unlikely(!pkts_n)) return 0; /* Prefetch first packet cacheline. */ - tx_prefetch_cqe(txq, txq->cq_ci); - tx_prefetch_cqe(txq, txq->cq_ci + 1); rte_prefetch0(*pkts); /* Start processing. */ txq_complete(txq); @@ -732,7 +713,6 @@ mlx5_tx_burst_mpw(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n) if (unlikely(!pkts_n)) return 0; /* Prefetch first packet cacheline. */ - tx_prefetch_cqe(txq, txq->cq_ci); rte_prefetch0(tx_mlx5_wqe(txq, txq->wqe_ci)); rte_prefetch0(tx_mlx5_wqe(txq, txq->wqe_ci + 1)); /* Start processing. */ @@ -937,7 +917,6 @@ mlx5_tx_burst_mpw_inline(void *dpdk_txq, struct rte_mbuf **pkts, if (unlikely(!pkts_n)) return 0; /* Prefetch first packet cacheline. */ - tx_prefetch_cqe(txq, txq->cq_ci); rte_prefetch0(tx_mlx5_wqe(txq, txq->wqe_ci)); rte_prefetch0(tx_mlx5_wqe(txq, txq->wqe_ci + 1)); /* Start processing. */