Case Study of TCP/IP tunings for High Performance Interconnects

TCP/IP remains a central protocol for high performance computers. Even when user codes are utilizing RDMA for communications, TCP/IP is often required for communica- tions with system infrastructure such as parallel file systems or authorization servers. Supercomputers with non-Ethernet interconnects often have an TCP/IP stack configured such as the Internet Protocol over Infiniband network layer. There are very few supercomputers that do not use TCP/IP as a communications layer. While most system professionals understand how to tune the TCP buffer sizes in order to get better performance, there are many other TCP/IP tunings that must be considered in order to get a high performing TCP network