Can I modify the HW_RATE_LIMIT of a qp dynamically when running perftest?

[DillionApple]

I want to ask a question: can I use ibv_modify_qp to dynamically change the qp sending rate after the qp is set to RTS state. My congestion control algorithm needs this to eliminate the congestions in the IB network.

I have tried in my testbed, which equipped with an ConnectX-6 Infiniband/VPI Adapter. But when I use ibv_modify_qp to modify the qp's static rate (with flag IB_QP_AV) after the qp is in RTS state, it always returns an error.

...
attr.ah_attr.static_rate = 7; // 40Gbps
...
ibv_modify_qp(qp, &attr, IB_QP_AV); // this returns 22
...

Any suggestions for this?