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net/mlx4_en: XDP_TX, assign constant values of TX descs on ring creaion

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In XDP_TX, some fields in tx_info and tx_desc are constants across
all entries of the different XDP_TX rings.
Assign values to these fields on ring creation time, rather than in
data-path.

Patchset performance tests:
Tested on ConnectX3Pro, Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz
Single queue no-RSS optimization ON.

XDP_TX packet rate:
------------------------------
Before    | After     | Gain |
13.7 Mpps | 14.0 Mpps | %2.2 |
------------------------------

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tariq Toukan 2017-10-11 13:17:27 +03:00 committed by David S. Miller
parent f6f0aa9741
commit f025fd6061
3 changed files with 27 additions and 14 deletions
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1
drivers/net/ethernet/mellanox/mlx4/en_netdev.c
View file

@ -1752,6 +1752,7 @@ int mlx4_en_start_port(struct net_device *dev)
mlx4_en_arm_cq(priv, cq);
} else {
mlx4_en_init_tx_xdp_ring_descs(priv, tx_ring);
mlx4_en_init_recycle_ring(priv, i);
/* XDP TX CQ should never be armed */
}

38
drivers/net/ethernet/mellanox/mlx4/en_tx.c
View file

@ -1085,14 +1085,35 @@ tx_drop:
#define MLX4_EN_XDP_TX_REAL_SZ (((CTRL_SIZE + MLX4_EN_XDP_TX_NRTXBB * DS_SIZE) \
/ 16) & 0x3f)
void mlx4_en_init_tx_xdp_ring_descs(struct mlx4_en_priv *priv,
struct mlx4_en_tx_ring *ring)
{
int i;
for (i = 0; i < ring->size; i++) {
struct mlx4_en_tx_info *tx_info = &ring->tx_info[i];
struct mlx4_en_tx_desc *tx_desc = ring->buf +
(i << LOG_TXBB_SIZE);
tx_info->map0_byte_count = PAGE_SIZE;
tx_info->nr_txbb = MLX4_EN_XDP_TX_NRTXBB;
tx_info->data_offset = offsetof(struct mlx4_en_tx_desc, data);
tx_info->ts_requested = 0;
tx_info->nr_maps = 1;
tx_info->linear = 1;
tx_info->inl = 0;
tx_desc->data.lkey = ring->mr_key;
tx_desc->ctrl.qpn_vlan.fence_size = MLX4_EN_XDP_TX_REAL_SZ;
tx_desc->ctrl.srcrb_flags = priv->ctrl_flags;
}
}
netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_ring *rx_ring,
struct mlx4_en_rx_alloc *frame,
struct mlx4_en_priv *priv, unsigned int length,
int tx_ind, bool *doorbell_pending)
{
union mlx4_wqe_qpn_vlan qpn_vlan = {
.fence_size = MLX4_EN_XDP_TX_REAL_SZ,
};
struct mlx4_en_tx_desc *tx_desc;
struct mlx4_en_tx_info *tx_info;
struct mlx4_wqe_data_seg *data;
@ -1124,20 +1145,12 @@ netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_ring *rx_ring,
tx_info->page = frame->page;
frame->page = NULL;
tx_info->map0_dma = dma;
tx_info->map0_byte_count = PAGE_SIZE;
tx_info->nr_txbb = MLX4_EN_XDP_TX_NRTXBB;
tx_info->nr_bytes = max_t(unsigned int, length, ETH_ZLEN);
tx_info->data_offset = offsetof(struct mlx4_en_tx_desc, data);
tx_info->ts_requested = 0;
tx_info->nr_maps = 1;
tx_info->linear = 1;
tx_info->inl = 0;
dma_sync_single_range_for_device(priv->ddev, dma, frame->page_offset,
length, PCI_DMA_TODEVICE);
data->addr = cpu_to_be64(dma + frame->page_offset);
data->lkey = ring->mr_key;
dma_wmb();
data->byte_count = cpu_to_be32(length);
@ -1152,9 +1165,6 @@ netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_ring *rx_ring,
ring->prod += MLX4_EN_XDP_TX_NRTXBB;
tx_desc->ctrl.qpn_vlan = qpn_vlan;
tx_desc->ctrl.srcrb_flags = priv->ctrl_flags;
/* Ensure new descriptor hits memory
* before setting ownership of this descriptor to HW
*/

2
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
View file

@ -705,6 +705,8 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
int node, int queue_index);
void mlx4_en_destroy_tx_ring(struct mlx4_en_priv *priv,
struct mlx4_en_tx_ring **pring);
void mlx4_en_init_tx_xdp_ring_descs(struct mlx4_en_priv *priv,
struct mlx4_en_tx_ring *ring);
int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
struct mlx4_en_tx_ring *ring,
int cq, int user_prio);