When Inline-Receive is active, the HCA may write received data in to the receive WQE or CQE. Using Inline-Receive saves PCIe read transaction since the HCA does not need to read the scatter list, therefore it improves performance in case of short receive –messages. On poll CQ, the driver copies the received data from WQE/CQE to the user’s buffers. Therefore, apart from querying Inline-Receive capability and Inline-Receive activation the feature is transparent to user application.

Inline Receive Experimental Verbs 

• ibv_exp_query_device
  • inline_recv_size
• ibv_exp_create_qp
  • max_inl_recv
• ibv_exp_create_dct
  • inline_size

Inline Receive Experimental Device Attributes

IBV_EXP_DEVICE_ATTR_INLINE_RECV_SZ

Inline Receive RDMA-Core Verbs

• mlx5dv_create_qp
  • MLX5DV_QP_CREATE_ALLOW_SCATTER_TO_CQE

Inline Receive RDMA-Core Environmental Variables

MLX5_SCATTER_TO_CQE

Relevant Man Pages

mlx5dv_create_qp: https://github.com/linux-rdma/rdma-core/blob/master/providers/mlx5/man/mlx5dv_create_qp.3.md