BFRP: Endpoint Congestion Avoidance Through Bilateral Flow Reservation

Abstract

In HPC, endpoint congestion is a bottleneck in the network and seriously affects the performance of the system. The endpoint congestion can be effectively mitigated by quickly responding to the network and reducing the injection rate of the source. However, most of the prior works do not consider the impact of flow completion time on system performance, but only focus on the packet latency and perform scheduling at packet granularity. For HPC applications, the flow completion time and throughput are the metrics that determines the speed of application execution. Although prior works reduce package latency, they do not fundamentally reduce the flow latency in flow level. In this paper, we propose the bilateral flow-based reservation protocol (BFRP). BFRP quickly responds to network conditions through light-weight bilateral reservation mechanism and can effectively avoid the formation of endpoint congestion. BFRP also schedules packets based on flows, and smallest flow is preferentially sent to decrease the average flow latency. BFRP ensures the source and destination send or receive flows according to the allocated time slices without any conflict at both ends. We evaluate our BFRP protocol against state-of-the-art reservation-based protocol, speculative reservation protocol(SRP), and the simulation results show that the flow latency can be reduced by 27.68% under hotspot traffic with fixed flow size and 24.59% under uniform traffic with fixed flow size.