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 <nelio.laranjeiro at 6wind.com>
Acked-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>
---
drivers/net/mlx5/mlx5_rxtx.c | 21 ---------------------
1 file changed, 21 deletions(-)
diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index 4b8c197..9f74fd4 100644
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -348,23 +348,6 @@ mlx5_tx_dbrec(struct txq *txq)
}
/**
- * 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.
*
* @param dpdk_txq
@@ -395,8 +378,6 @@ 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);
@@ -733,7 +714,6 @@ 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. */
@@ -938,7 +918,6 @@ 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. */
--
2.1.4
