drbd with rdma occur: Not sending flow_control mgs, no receive window!

[wswseyes]

drbd version: 9.2.7

I create one drbd(2replica,10GiB) resource with Net/transport: rdma;

When drbd sync or use fio test, even seq write(bs=128K, numjobs=1,iodepth=64), it occur: "Not sending flow_control mgs, no receive window!".

This makes it impossible for me to test performance of drbd with rdma. What can I do？

[vmichel-ephe]

same error here, unsure how to dig further.
I can get fio tests to complete with some settings activated :
linstor resource-group drbd-options --transport rdma --c-plan-ahead 0 --c-fill-target 24M --c-min-rate 80M --c-max-rate 1G --max-buffers 36k --sndbuf-size 1024k --rcvbuf-size 2048k --max-epoch-size 20000 $POOL

But then the performances are abysmal.

[vmichel-ephe]

ok, didnt read enough before posting there.
here is some documentation that fix this error :
https://kb.linbit.com/mitigate-flow-control-rmda