A Performance Analysis of the Ammasso RDMA Enabled Ethernet Adapter and its iWARP API

Network speeds are increasing well beyond the capabilities of today's CPUs to efficiently handle the traffic. This bottleneck at the CPU causes the processor to spend more of its time handling communication and less time on actual processing. As network speeds reach 10 Gb/s and more, the CPU simply can not keep up with the data. Various methods have been proposed to solve this problem. High performance interconnects, such as Infiniband, have been developed that rely on RDMA and protocol offload in order to achieve higher throughput and lower latency. In this paper we evaluate the feasibility of a similar approach which, unlike existing high performance interconnects, requires no special infrastructure. RDMA over Ethernet, otherwise known as iWARP, facilitates the zero copy exchange of data over ordinary local area networks. Since it is based on TCP, iWARP enables RDMA in the wide area network as well. This paper provides a look into the performance of one of the earliest commodity implementations of this emerging technology, the Ammasso 1100 RNIC