An Efficient Implementation of Virtual Interface Architecture using Adaptive Transfer Mechanism on Myrinet

The user-level communication is investigated by many researches, in order to resolve the performance degradation of cluster systems due to inefficient communication protocols. It removes the kernel intervention from the critical communication path. Recently, Intel, Microsoft and Compaq introduce the Virtual Interface Architecture (VIA), a standard for userlevel communication. However, the existing VIA implementation shows low performance in transferring small messages, because it uses a single mechanism to transfer messages without regard to their message size. In this paper, we implement a high performance VIA, KVIA (Kaist VIA). KVIA, based on descriptor and message size, dynamically selects a proper transfer 1 mechanism. This implementation effectively handles not only large messages but also small messages. Thus, it can be better applied to the systems that frequently use small messages (e.g., lock protocols for software distributed shared memory). The performance of KVIA is reported using round-trip latency and one-way bandwidth. Our results show the round-trip latency of 40 micro-seconds and the maximum one-way bandwidth of 950 Mbits per second, which is about 74 % of Myrinet link's peak bandwidth. 1