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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 <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2014-10-05 12:35:11 +03:00 committed by David S. Miller
parent 98b1634941
commit 6a4e81211f
2 changed files with 12 additions and 8 deletions
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17
drivers/net/ethernet/mellanox/mlx4/en_tx.c
View File

@ -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++;
}

3
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
View File

@ -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;