Date Posted: 8/27/2019

Best Student Paper this year at ACM SIGCOMM ’19 was awarded to “PicNIC: Predictable Virtualized NIC,” with lead author Praveen Kumar, Ph.D. candidate at Cornell CS, advised by CS Associate Professor Nate Foster. The paper was co-authored with a team from Google, including: Nandita Dukkipati, Nathan Lewis, Yi Cui, Yaogong Wang, Chonggang Li, Valas Valancius, Jake Adriaens, Steve Gribble, and Amin Vahdat. According to Kumar, “the paper shows how to make public cloud computing platforms more predictable by eliminating harmful network interference between different tenants.” This latest distinction marks the second year in a row that the award has gone to a paper involving Cornell Ph.D. students: last year, a paper co-authored by Saksham Agarwal and Shijin Rajakrishnan received the prize.

The project is described this way by the authors:

Network virtualization stacks are the linchpins of public clouds. A key goal is to provide performance isolation so that workloads on one Virtual Machine (VM) do not adversely impact the network experience of another VM. Using data from a major public cloud provider, we systematically characterize how performance isolation can break in current virtualization stacks and find a fundamental tradeoff between isolation and resource multiplexing for efficiency. In order to provide predictable performance, we propose a new system called PicNIC that shares resources efficiently in the com- mon case while rapidly reacting to ensure isolation. PicNIC builds on three constructs to quickly detect isolation breakdown and to enforce it when necessary: CPU-fair weighted fair queues at re- ceivers, receiver-driven congestion control for backpressure, and sender-side admission control with shaping. Based on an extensive evaluation, we show that this combination ensures isolation for VMs at sub-millisecond timescales with negligible overhead. 

Read the full paper at this link.