net/mlx5e: Support TX packet copy into WQE

AKA inline WQE.
A TX latency optimization to save data gather DMA reads.
Controlled by ETHTOOL_TX_COPYBREAK.

Signed-off-by: Achiad Shochat <achiad@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 61d8433392aaa40195f1f5165b5e9af3ed2fb890..d9dc506188c822c656f992bcf8f3a4a990770a33 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -196,6 +196,7 @@ struct mlx5e_params {
        bool lro_en;
        u32 lro_wqe_sz;
        u8  rss_hfunc;
+       u16 tx_max_inline;
 };
 
 enum {
@@ -520,3 +521,4 @@ static inline void mlx5e_cq_arm(struct mlx5e_cq *cq)
 }
 
 extern const struct ethtool_ops mlx5e_ethtool_ops;
+u16 mlx5e_get_max_inline_cap(struct mlx5_core_dev *mdev);

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
index cb28535705041d91f90deb26dcacf2332eadf8b2..14fd82c0d18e30348f23a9f4048fd8fe48a1ffc1 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -699,6 +699,57 @@ static int mlx5e_set_rxfh(struct net_device *netdev, const u32 *indir,
        return err;
 }
 
+static int mlx5e_get_tunable(struct net_device *dev,
+                            const struct ethtool_tunable *tuna,
+                            void *data)
+{
+       const struct mlx5e_priv *priv = netdev_priv(dev);
+       int err = 0;
+
+       switch (tuna->id) {
+       case ETHTOOL_TX_COPYBREAK:
+               *(u32 *)data = priv->params.tx_max_inline;
+               break;
+       default:
+               err = -EINVAL;
+               break;
+       }
+
+       return err;
+}
+
+static int mlx5e_set_tunable(struct net_device *dev,
+                            const struct ethtool_tunable *tuna,
+                            const void *data)
+{
+       struct mlx5e_priv *priv = netdev_priv(dev);
+       struct mlx5_core_dev *mdev = priv->mdev;
+       struct mlx5e_params new_params;
+       u32 val;
+       int err = 0;
+
+       switch (tuna->id) {
+       case ETHTOOL_TX_COPYBREAK:
+               val = *(u32 *)data;
+               if (val > mlx5e_get_max_inline_cap(mdev)) {
+                       err = -EINVAL;
+                       break;
+               }
+
+               mutex_lock(&priv->state_lock);
+               new_params = priv->params;
+               new_params.tx_max_inline = val;
+               err = mlx5e_update_priv_params(priv, &new_params);
+               mutex_unlock(&priv->state_lock);
+               break;
+       default:
+               err = -EINVAL;
+               break;
+       }
+
+       return err;
+}
+
 const struct ethtool_ops mlx5e_ethtool_ops = {
        .get_drvinfo       = mlx5e_get_drvinfo,
        .get_link          = ethtool_op_get_link,
@@ -715,4 +766,6 @@ const struct ethtool_ops mlx5e_ethtool_ops = {
        .set_settings      = mlx5e_set_settings,
        .get_rxfh          = mlx5e_get_rxfh,
        .set_rxfh          = mlx5e_set_rxfh,
+       .get_tunable       = mlx5e_get_tunable,
+       .set_tunable       = mlx5e_set_tunable,
 };

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 57cc8960b73bd3b989e2ccbe9be2bc3d068e1427..c55fad431cbf25a34b6142368f1f711eec0fae3e 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -41,6 +41,7 @@ struct mlx5e_rq_param {
 struct mlx5e_sq_param {
        u32                        sqc[MLX5_ST_SZ_DW(sqc)];
        struct mlx5_wq_param       wq;
+       u16                        max_inline;
 };
 
 struct mlx5e_cq_param {
@@ -514,6 +515,7 @@ static int mlx5e_create_sq(struct mlx5e_channel *c,
        sq->wq.db       = &sq->wq.db[MLX5_SND_DBR];
        sq->uar_map     = sq->uar.map;
        sq->bf_buf_size = (1 << MLX5_CAP_GEN(mdev, log_bf_reg_size)) / 2;
+       sq->max_inline  = param->max_inline;
 
        err = mlx5e_alloc_sq_db(sq, cpu_to_node(c->cpu));
        if (err)
@@ -1020,6 +1022,7 @@ static void mlx5e_build_sq_param(struct mlx5e_priv *priv,
        MLX5_SET(wq, wq, pd,            priv->pdn);
 
        param->wq.buf_numa_node = dev_to_node(&priv->mdev->pdev->dev);
+       param->max_inline = priv->params.tx_max_inline;
 }
 
 static void mlx5e_build_common_cq_param(struct mlx5e_priv *priv,
@@ -1703,6 +1706,15 @@ static int mlx5e_check_required_hca_cap(struct mlx5_core_dev *mdev)
        return 0;
 }
 
+u16 mlx5e_get_max_inline_cap(struct mlx5_core_dev *mdev)
+{
+       int bf_buf_size = (1 << MLX5_CAP_GEN(mdev, log_bf_reg_size)) / 2;
+
+       return bf_buf_size -
+              sizeof(struct mlx5e_tx_wqe) +
+              2 /*sizeof(mlx5e_tx_wqe.inline_hdr_start)*/;
+}
+
 static void mlx5e_build_netdev_priv(struct mlx5_core_dev *mdev,
                                    struct net_device *netdev,
                                    int num_comp_vectors)
@@ -1721,6 +1733,7 @@ static void mlx5e_build_netdev_priv(struct mlx5_core_dev *mdev,
                MLX5E_PARAMS_DEFAULT_TX_CQ_MODERATION_USEC;
        priv->params.tx_cq_moderation_pkts =
                MLX5E_PARAMS_DEFAULT_TX_CQ_MODERATION_PKTS;
+       priv->params.tx_max_inline         = mlx5e_get_max_inline_cap(mdev);
        priv->params.min_rx_wqes           =
                MLX5E_PARAMS_DEFAULT_MIN_RX_WQES;
        priv->params.rx_hash_log_tbl_sz    =

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
index 03f28f438e55ab690cc865b6bc3509a53d280e25..351ac6982e226ff5a82c11e8db604809b8177588 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
@@ -112,7 +112,15 @@ u16 mlx5e_select_queue(struct net_device *dev, struct sk_buff *skb,
 static inline u16 mlx5e_get_inline_hdr_size(struct mlx5e_sq *sq,
                                            struct sk_buff *skb)
 {
-#define MLX5E_MIN_INLINE 16 /* eth header with vlan (w/o next ethertype) */
+       /* Some NIC TX decisions, e.g loopback, are based on the packet
+        * headers and occur before the data gather.
+        * Therefore these headers must be copied into the WQE
+        */
+#define MLX5E_MIN_INLINE (ETH_HLEN + 2/*vlan tag*/)
+
+       if (skb_headlen(skb) <= sq->max_inline)
+               return skb_headlen(skb);
+
        return MLX5E_MIN_INLINE;
 }