NAME

       mlx5dv_map_ah_to_qp  - Map the destination path information in address handle (AH) to the information ex‐
       tracted from the qp.

SYNOPSIS

              #include <infiniband/mlx5dv.h>

              int mlx5dv_map_ah_to_qp(struct ibv_ah *ah, uint32_t qp_num);

DESCRIPTION

       This API maps the destination path information in address handle (ah) to the information  extracted  from
       the qp (e.g. congestion control from ECE).

       This  API  serves  as  an enhancement to DC and UD QPs to achieve better performance by using per-address
       congestion control (CC) algorithms, enabling DC/UD QPs to use multiple CC algorithms in the same datacen‐
       ter.

       The mapping created by this API is implicitly destroyed when the address handle is destroyed.  It is  not
       affected by the destruction of QP qp_num.

       A  duplicate  mapping to the same address handle is ignored.  As this API is just a hint for the hardware
       in this case it would do nothing and return success regardless of the new qp_num ECE.

       The function must be called after ECE negotiation/preconfiguration was done by some external means.

ARGUMENTS

       ah     The target’s address handle.

       qp_num The initiator QP from which congestion control information is extracted from its ECE.

RETURN VALUE

       Upon success, returns 0; Upon failure, the value of errno is returned.

SEE ALSO

       rdma_cm(7), rdma_get_remote_ece(3), ibv_query_ece(3), ibv_set_ece(3)

AUTHOR

       Yochai Cohen <yochai@nvidia.com>

       Patrisious Haddad <phaddad@nvidia.com>

                                                                                          mlx5dv_map_ah_to_qp(3)