I'm trying to find a short "Hello World" example that uses Infiniband with libibverbs. This goes into a good direction, but writing "Hello World" to the terminal should be possible in less than 800 lines. I was hoping for something like this.
You could perhaps try using librdmacm. It wraps some of libibverbs functionality and especially assists in setting up connections. The rdma_server and rdma_client examples take less than 200 lines each.