The Extended Sockets Interface for Accessing Rdma Hardware

The Extended Sockets API (ES-API) is a specification published by the OpenGroup that defines extensions to the traditional socket API which include two major new features: asynchronous I/O, and memory registration. These features enable programmers to take advantage of today’s multi-core processors and Remote Direct Memory Access (RDMA) network hardware, such as iWARP and InfiniBand interfaces, in a convenient yet efficient manner. This paper describes the UNH EXS interface, an implementation of the ES-API that provides additional API facilities which enable a programmer to utilize RDMA network hardware while selectively choosing those features of this interface that are most germane to the particular application. In addition, the UNH EXS interface is implemented entirely in user space on the Linux operating system. This provides easy porting, modification and adoption of UNHEXS, since it requires no changes to existing Linux kernels. Preliminary results demonstrate that applications based on EXS can achieve high bandwidth utilization and low CPU overhead.