Server network scalability and TCP offload

Abstract

Server network performance is increasingly dominated by poorly scaling operations such as I/O bus crossings, cache misses and interrupts. Their overhead prevents performance from scaling even with increased CPU, link or I/O bus bandwidths. These operations can be reduced by redesigning the host/adapter interface to exploit additional processing on the adapter. Of oading processing to the adapter is bene cial not only because it allows more cycles to be applied but also of the changes it enables in the host/adapter interface. As opposed to other approaches such as RDMA, TCP of oad provides bene-ts without requiring changes to either the transport protocol or API. We have designed a new host/adapter interface that exploits of oaded processing to reduce poorly scaling operations. We have implemented a prototype of the design including both host and adapter software components. Experimental evaluation with simple network benchmarks indicates our design signi cantly reduces I/O bus crossings and holds promise to reduce other poorly scaling operations as well.