iWarp protocol kernel space software implementation

Zero-copy, RDMA, and protocol offload are three very important characteristics of high performance interconnects. Previous networks that made use of these techniques were built upon proprietary, and often expensive, hardware. With the introduction of iWarp, it is now possible to achieve all three over existing low-cost TCP/IP networks. iWarp is a step in the right direction, but requires an expensive RNIC to enable zero-copy, RDMA, and protocol offload. While the hardware is expensive at present, given that iWarp is based on a commodity interconnect, prices fall. In the meantime only the most critical of servers make use of iWarp, but in order to take advantage of the RNIC both sides must be so equipped. It is for this reason that we have implemented the iWarp protocol in software. This allows a server equipped with an RNIC to exploit its advantages even if the client does not have an RNIC. While throughput and latency do not improve by doing this, the server with the RNIC does experience a dramatic reduction in system load. This means that the server is much more scalable, and can handle many more clients than would otherwise be possible with the usual sockets/TCP/IP protocol stack