How can I obtain the real rate_limit of qp

Hi sirs,
I use two servers equipped with ConnectX-5 adapter cards connected back-to-back to achieve the Packet Pacing Coding example now. And the version of OFED is v5.8- LTS.
I try to modify the QP rate limit and use ibv_ query_ qp function to obtain the modified QP rate limit. Unfortunately, no matter how I modify the speed, I will get the same result in the end. All of them are 124.

Why is that? What should I do to get a real qp rate limit?

IBTA define rate limit on QP. You can use Verbs API below implement that.

   #include <infiniband/verbs.h>

   int ibv_modify_qp(struct ibv_qp *qp, struct ibv_qp_attr *attr,
                     int attr_mask);

   #include <infiniband/verbs.h>

   int ibv_modify_qp_rate_limit(struct ibv_qp *qp, struct ibv_qp_rate_limit_attr *attr);

I’m sorry I didn’t express my question clearly.
I successfully limit the rate of QP by the API ibv_modify_qp_rate_limit which you pointed. In the next step, I hope to get the rate after QP is limited in a certain way. I tried this, as follows
Finally, I get the result is 0. But I set the rate_limit to 10000Kbps. Whatever I set the rate_limit to, the printed result always is 0. The other attributes of QP which are printed are correct.
I wonder why is that and how I can print the real rate_limit attribute of QP.

modify QP and query QP API define different qp_attr and mask. On query QP attr rate_limit not supported.

 struct ibv_qp_attr {
           enum ibv_qp_state       qp_state;            /* Current QP state */
           enum ibv_qp_state       cur_qp_state;        /* Current QP state - irrelevant for ibv_query_qp */
           enum ibv_mtu            path_mtu;            /* Path MTU (valid only for RC/UC QPs) */
           enum ibv_mig_state      path_mig_state;      /* Path migration state (valid if HCA supports APM) */
           uint32_t                qkey;                /* Q_Key of the QP (valid only for UD QPs) */
           uint32_t                rq_psn;              /* PSN for receive queue (valid only for RC/UC QPs) */
           uint32_t                sq_psn;              /* PSN for send queue */
           uint32_t                dest_qp_num;         /* Destination QP number (valid only for RC/UC QPs) */
           unsigned int            qp_access_flags;     /* Mask of enabled remote access operations (valid only for RC/UC QPs) */
           struct ibv_qp_cap       cap;                 /* QP capabilities */
           struct ibv_ah_attr      ah_attr;             /* Primary path address vector (valid only for RC/UC QPs) */
           struct ibv_ah_attr      alt_ah_attr;         /* Alternate path address vector (valid only for RC/UC QPs) */
           uint16_t                pkey_index;          /* Primary P_Key index */
           uint16_t                alt_pkey_index;      /* Alternate P_Key index */
           uint8_t                 en_sqd_async_notify; /* Enable SQD.drained async notification - irrelevant for ibv_query_qp */
           uint8_t                 sq_draining;         /* Is the QP draining? (Valid only if qp_state is SQD) */
           uint8_t                 max_rd_atomic;       /* Number of outstanding RDMA reads & atomic operations on the destination QP (valid only for RC QPs) */
           uint8_t                 max_dest_rd_atomic;  /* Number of responder resources for handling incoming RDMA reads & atomic operations (valid only for RC QPs) */
           uint8_t                 min_rnr_timer;       /* Minimum RNR NAK timer (valid only for RC QPs) */
           uint8_t                 port_num;            /* Primary port number */
           uint8_t                 timeout;             /* Local ack timeout for primary path (valid only for RC QPs) */
           uint8_t                 retry_cnt;           /* Retry count (valid only for RC QPs) */
           uint8_t                 rnr_retry;           /* RNR retry (valid only for RC QPs) */
           uint8_t                 alt_port_num;        /* Alternate port number */
           uint8_t                 alt_timeout;         /* Local ack timeout for alternate path (valid only for RC QPs) */

I think no API can “print the real rate_limit attribute of QP”.

alternative you can set QP SL then print SLx xmit by MAD CMD. Then calculate。

root@mtbc-r740-06:~# perfquery 7 1 -X

PortXmitDataSL counters: Lid 7 port 1