CPU Overhead is being utilized at maximum capacity over infiniband on file transfer applications

I am running a file transfer over Infiniband Ethernet and using Reliable Communication (RC) for data transfer. I am noticing that Infiniband CPU overhead is at maximum regarding large file transfers or any file transfer with large buffer size. Infiniband CPU overhead reaches 100% over a single thread and even distributing it on multiple threads creates the same scenario. Is it a usual behavior of InfiniBand applications?