I have CX3 and CX5 adapters. And the same code of application using ibverbs api. When use CX3, field of TC in GRH has value 0x00. But when I use CX5 GRH TC has value 0x20. How can I control it. RDMA_CM set option I can not use, because use ibverbs api. May be via mlxconfig? Any help would be useful. Thanks.
P.S. Any changes via linux utils in MLNX_OFED did nothing for me.
Hello Ivan,
ibv_create_ah() holds this info and is used when calling ibv_post_send()
Please refer to
https://www.mellanox.com/related-docs/prod_software/RDMA_Aware_Programming_user_manual.pdf
Section 3.4.15 ibv_create_ah
ibv_create_ah creates an AH. An AH contains all of the necessary data to reach a remote destination.
In connected transport modes (RC, UC) the AH is associated with a queue pair (QP). In
the datagram transport modes (UD), the AH is associated with a work request (WR).
struct ibv_ah_attr is defined as follows:
struct ibv_ah_attr
{
struct ibv_global_route grh;
uint16_t dlid;
uint8_t sl;
uint8_t src_path_bits;
uint8_t static_rate;
uint8_t is_global;
uint8_t port_num;
};
In the ibv_global_route struct the user should pass the TClass
struct ibv_global_route is defined as follows:
struct ibv_global_route
{
union ibv_gid dgid;
uint32_t flow_label;
uint8_t sgid_index;
uint8_t hop_limit;
uint8_t traffic_class;
};
Best Regards,
Anatoly