Performance Isolation Anomalies in RDMA

Abstract

To meet the increasing throughput and latency demands of modern applications, many operators are rapidly deploying RDMA in their datacenters. At the same time, developers are re-designing their software to take advantage of RDMA's benefits for individual applications. However, when it comes to RDMA's performance, many simple questions remain open. In this paper, we consider the performance isolation characteristics of RDMA. Specifically, we conduct three sets of experiments - three combinations of one throughput-sensitive flow and one latency-sensitive flow - in a controlled environment, observe large discrepancies in RDMA performance with and without the presence of a competing flow, and describe our progress in identifying plausible root-causes.