From 6a4e81211f475561ed87c613216f981fbef8b7fc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:11 +0300 Subject: [PATCH] net/mlx4_en: Avoid calling bswap in tx fast path - doorbell_qpn is stored in the cpu_to_be32() way to avoid bswap() in fast path. - mdev->mr.key stored in ring->mr_key to also avoid bswap() and access to cold cache line. Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 17 ++++++++++------- drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 3 ++- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index eaf23eb..322cda3 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -195,7 +195,8 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv, memset(ring->buf, 0, ring->buf_size); ring->qp_state = MLX4_QP_STATE_RST; - ring->doorbell_qpn = ring->qp.qpn << 8; + ring->doorbell_qpn = cpu_to_be32(ring->qp.qpn << 8); + ring->mr_key = cpu_to_be32(mdev->mr.key); mlx4_en_fill_qp_context(priv, ring->size, ring->stride, 1, 0, ring->qpn, ring->cqn, user_prio, &ring->context); @@ -654,7 +655,6 @@ static void mlx4_bf_copy(void __iomem *dst, const void *src, netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) { struct mlx4_en_priv *priv = netdev_priv(dev); - struct mlx4_en_dev *mdev = priv->mdev; struct device *ddev = priv->ddev; struct mlx4_en_tx_ring *ring; struct mlx4_en_tx_desc *tx_desc; @@ -769,7 +769,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) goto tx_drop_unmap; data->addr = cpu_to_be64(dma); - data->lkey = cpu_to_be32(mdev->mr.key); + data->lkey = ring->mr_key; wmb(); data->byte_count = cpu_to_be32(skb_frag_size(frag)); --data; @@ -787,7 +787,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) goto tx_drop_unmap; data->addr = cpu_to_be64(dma); - data->lkey = cpu_to_be32(mdev->mr.key); + data->lkey = ring->mr_key; wmb(); data->byte_count = cpu_to_be32(byte_count); } @@ -879,9 +879,12 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) send_doorbell = !skb->xmit_more || netif_xmit_stopped(ring->tx_queue); + real_size = (real_size / 16) & 0x3f; + if (ring->bf_enabled && desc_size <= MAX_BF && !bounce && !vlan_tx_tag_present(skb) && send_doorbell) { - tx_desc->ctrl.bf_qpn |= cpu_to_be32(ring->doorbell_qpn); + tx_desc->ctrl.bf_qpn = ring->doorbell_qpn | + cpu_to_be32(real_size); op_own |= htonl((bf_index & 0xffff) << 8); /* Ensure new descriptor hits memory @@ -911,8 +914,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) tx_desc->ctrl.owner_opcode = op_own; if (send_doorbell) { wmb(); - iowrite32be(ring->doorbell_qpn, - ring->bf.uar->map + MLX4_SEND_DOORBELL); + iowrite32(ring->doorbell_qpn, + ring->bf.uar->map + MLX4_SEND_DOORBELL); } else { ring->xmit_more++; } diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h index b7bde95..ab34461 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h @@ -279,7 +279,8 @@ struct mlx4_en_tx_ring { u16 stride; u16 cqn; /* index of port CQ associated with this ring */ u32 buf_size; - u32 doorbell_qpn; + __be32 doorbell_qpn; + __be32 mr_key; void *buf; struct mlx4_en_tx_info *tx_info; u8 *bounce_buf; -- 2.7.4