net/mlx4: verify Tx max sges

Max number of Tx scatter-gather entries is a property of the device
and is queried at init. This value was not changed in a while and
most probably will not be changed in the future, Therefore and
in order to enhance Tx performance, the Tx max-sge value is hardcoded
in mlx4 PRM code.
This patch adds a verification that the above assumption still holds
and that the hardcoded value is still supported by the mlx4 hardware.

Signed-off-by: Moti Haimovsky <motih@mellanox.com>
Acked-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>

diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c
index 4bc4a6f..61c5bf4 100644 (file)
--- a/drivers/net/mlx4/mlx4.c
+++ b/drivers/net/mlx4/mlx4.c
@@ -505,6 +505,7 @@ mlx4_pci_probe(struct rte_pci_driver *pci_drv, struct rte_pci_device *pci_dev)
                rte_errno = ENODEV;
                goto error;
        }
+       assert(device_attr.max_sge >= MLX4_MAX_SGE);
        for (i = 0; i < device_attr.phys_port_cnt; i++) {
                uint32_t port = i + 1; /* ports are indexed from one */
                struct ibv_context *ctx = NULL;

diff --git a/drivers/net/mlx4/mlx4_prm.h b/drivers/net/mlx4/mlx4_prm.h
index 217ea50..3803cbd 100644 (file)
--- a/drivers/net/mlx4/mlx4_prm.h
+++ b/drivers/net/mlx4/mlx4_prm.h
@@ -53,7 +53,10 @@
 #define MLX4_TXBB_SIZE (1 << MLX4_TXBB_SHIFT)
 
 /* Typical TSO descriptor with 16 gather entries is 352 bytes. */
-#define MLX4_MAX_WQE_SIZE 512
+#define MLX4_MAX_SGE 32
+#define MLX4_MAX_WQE_SIZE \
+       (MLX4_MAX_SGE * sizeof(struct mlx4_wqe_data_seg) + \
+        sizeof(struct mlx4_wqe_ctrl_seg))
 #define MLX4_SEG_SHIFT 4
 
 /* Send queue stamping/invalidating information. */