EMP

Modern interconnects like Myrinet and Gigabit Ethernet offer Gb/s speeds which has put the onus of reducing the communication latency on messaging software. This has led to the development of OS bypass protocols which removed the kernel from the critical path and hence reduced the end-to-end latency. With the advent of programmable NICs, many aspects of protocol processing can be offloaded from user space to the NIC leaving the host processor to dedicate more cycles to the application. Many host-offload messaging systems exist for Myrinet; however, nothing similar exits for Gigabit Ethernet. In this paper we propose Ethernet Message Passing (EMP), a completely new zero-copy, OS-bypass messaging layer for Gigabit Ethernet on Alteon NICs where the entire protocol processing is done at the NIC. This messaging system delivers very good performance (latency of 23 us, and throughput of 880 Mb/s). To the best of our knowledge, this is the first NIC-level implementation of a zero-copy message passing layer for Gigabit Ethernet.