Changhoon (Chang) Kim
I am a Principal Engineer at Google and work in the Net Infra group at GCP.
I was VP of Engineering at Moloco, a startup that provides cutting-edge ML and big-data processing solutions and services to the mobile and e-commerce industries. I was an adjunct professor at the CS department of Stanford University. Up until early 2021, I worked as CTO of Applications at Barefoot Division in Intel, and an Intel Fellow. I had also worked actively for P4.org, where I led various engineering and research projects regarding fully-programmable high-speed networking devices and their applications. Before getting involved with P4.org and Barefoot Networks, I had worked at Windows Azure, Microsoft’s cloud-service division and had led engineering and research projects on the architecture, performance, and management of datacenter networks.
I have knack of having interest in and working on a variety of topics, including large-scale ML and data-processing systems, applications of DNNs, ML infrastructure, programmable networking, domain-specific machine architectures, application acceleration, and debugging and diagnosis of large-scale distributed systems. Many of my engineering and research contributions — including In-band Network Telemetry, Tiny Packet Programs, VL2, Seawall, EyeQ, Ananta, and SEATTLE — are adopted in large production systems and services.
With my collaborators I received a few awards, including best paper awards from top-notch conferences, such as SIGCOMM, NSDI, and FAST. I was the recipient of Microsoft Rockstar Award 2013, an annual recognition for the strongest networking contributions Microsoft-wide. I received PhD in Computer Science at Princeton University, and MS/BS in Computer Engineering at Seoul National University.
CV (available upon request) | Google Scholar
SIGCOMM has recognized the VL2 work with 2019 ACM Test of Time Award. A brief summary of the work according to the award committee is as follows.
"This paper articulated the core design principles that have become the foundation for modern datacenter networks: scalable Clos topologies, randomized load-balanced routing, and virtual networks constructed by decoupling endpoint addresses and locations. By convincingly arguing for these principles, and providing one of the first glimpses into real-world datacenter network traffic characteristics, this paper has had enduring impact on both the practice of datacenter network design and the large body of research on the topic that has followed over the last decade."
Select Talks
Forwarding Plane: An Old New Frontier of Networking Research
Keynotes at ACM SOSR and ACM/IEEE ANCS, Mar and Jul 2018 respectively [slides]
Programming the Network Data Plane to Accelerate Applications
QCon, Mar 2018 [video]
In-band Network Telemetry
OVS Orbit -- Ben Pfaff's podcast, Nov 2017 [mp3]
Future of Network Monitoring
Tech Field Day, Jan 2017 [video]
Why Data Plane Will be Programmable For Good
Keynote at APNet, Aug 2017 [slides]
Subtle but Important Benefits of Programmable Data Planes
Keynote at NetPL workshop at SIGCOMM, Aug 2016 [video] [slides]
Select Publications
The nanoPU: A Nanosecond Network Stack for Datacenters
Stephen Ibanez, Alex Mallery, Serhat Arslan, Muhammad Shahbaz, Changhoon Kim, and Nick McKeown
USENIX Symposium on Operating Systems Design and Implementation (OSDI), July 2021
TEA: Enabling State-Intensive Network Functions on Programmable Switches
Daehyeok Kim, Zaoxing Liu, Yibo Zhu, Changhoon Kim, Jeongkeun Lee, Vyas Sekar, and Srinivasan Seshan
ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2020
Programmable Calendar Queues for High-speed Packet Scheduling
Naveen Kr. Sharma, Chenxingyu Zhao, Ming Liu, Pravein G. Kannan, Changhoon Kim, Arvind Krishnamurthy, and Anirudh Sivaraman
USENIX Symposium on Networked System Design and Implementation (NSDI), Apr 2020
DistCache: Provable Load Balancing for Large-Scale Storage Systems with Distributed Caching
Zaoxing Liu, Zhihao Bai, Zhenming Liu, Xiaozhou Li, Changhoon Kim, Vladimir Braverman, Xin Jin, and Ion Stoica
USENIX Conference on File and Storage Technologies (FAST), Feb 2019
Best Paper Award
Scaling Distributed Machine Learning with In-Network Aggregation
Amedeo Sapio, Marco Canini, Chen-Yu Ho, Jacob Nelson, Panos Kalnis, Changhoon Kim,
Arvind Krishnamurthy, Masoud Moshref, Dan R. K. Ports, and Peter Richtárik
Preprint on arXiv, Feb 2019
Fast String Searching on PISA
Theo Jepsen, Daniel Alvarez, Nate Foster, Changhoon Kim, Jeongkeun Lee, Masoud Moshref, and Robert Soulé
ACM SIGCOMM Symposium on Software Defined Networking Research (SOSR), Mar 2019
Generic External Memory For Switch Data Planes
Daehyeok Kim, Yibo Zhu, Changhoon Kim, Jeongkeun Lee, and Srinivasan Seshan
ACM Workshop on Hot Topics in Networks (HotNets), Nov 2018 [video]
NetChain: Scale-Free Sub-RTT Coordination
Xin Jin, Xiaozhou Li, Haoyu Zhang, Nate Foster, Jeongkeun Lee, Robert Soulé, Changhoon Kim, and Ion Stoica
USENIX Symposium on Networked System Design and Implementation (NSDI), Apr 2018 [slides & video]
Best Paper Award
NetCache: Balancing Key-Value Stores with Fast In-Network Caching
Xin Jin, Xiaozhou Li, Haoyu Zhang, Robert Soulé, Jeongkeun Lee, Nate Foster, Changhoon Kim, and Ion Stoica
ACM SIGOPS Symposium on Operating Systems Principles (SOSP), Oct 2017 [slides]
Language-Directed Hardware Design for Network Performance Monitoring
Srinivas Narayana, Anirudh Sivaraman, Vikram Nathan, Prateesh Goyal, Venkat Arun, Mohammad Alizadeh, Vimalkumar Jeyakumar, and Changhoon Kim
ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2017 [slides] [video]
Best Paper Award
SilkRoad: Making Stateful Layer-4 Load Balancing Fast and Cheap Using Switching ASICs
Rui Miao, Hongyi Zeng, Changhoon Kim, Jeongkeun Lee, and Minlan Yu
ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2017 [slides] [video]
Evaluating the Power of Flexible Packet Processing for Network Resource Allocation
Naveen Kr. Sharma, Antoine Kaufmann, Thomas Anderson, Changhoon Kim, Arvind Krishnamurthy,
Jacob Nelson, and Simon Peter
USENIX Symposium on Networked Systems Design and Implementation (NSDI), Mar 2017 [slides & video]
PISCES: A Programmable, Protocol-Independent Software Switch
Muhammad Shahbaz, Sean Choi, Ben Pfaff, Changhoon Kim, Nick Feamster, Nick McKeown,
and Jennifer Rexford
ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2016
Packet Transactions: High-Level Programming for Line-Rate Switches
Anirudh Sivaraman, Alvin Cheung, Mihai Budiu, Changhoon Kim, Mohammad Alizadeh, Hari Balakrishnan, George Varghese, Nick McKeown, and Steve Licking
ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2016
FlowRadar: A Better NetFlow for Data Centers
Yuliang Li, Rui Miao, Changhoon Kim, and Minlan Yu.
USENIX Symposium on Networked Systems Design and Implementation (NSDI), Mar 2016
HULA: Scalable Load Balancing Using Programmable Data Planes
Naga Katta, Mukesh Hira, Changhoon Kim, Anirudh Sivaraman, and Jennifer Rexford
ACM SIGCOMM Symposium on Software Defined Networking Research (SOSR), Mar 2016
Programming the Network Dataplane in P4 (in Chinese)
Changhoon Kim, Ron Kao, and Nick McKeown
Communications of the China Computer Federation (CCF), Jul 2016
In-band Network Telemetry via Programmable Data Planes
Changhoon Kim, Anirudh Sivaraman, Naga Katta, Antonin Bas, Advait Dixit, and Lawrence J Wobker
Demo Session for ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2015
Millions of Little Minions: Using packets for low latency network programming and visibility
Vimalkumar Jeyakumar, Mohammad Alizadeh, Yilong Geng, Changhoon Kim, and David Mazières
ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2014
Ananta: Cloud scale load balancing
Parveen Patel, Deepak Bansal, Lihua Yuan, Ashwin Murthy, Albert Greenberg, David A Maltz, Randy Kern, Hemant Kumar, Marios Zikos, Hongyu Wu, Changhoon Kim, and Naveen Karri
ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2013
EyeQ: Practical Network Performance Isolation at the Network Edge
Vimalkumar Jeyakumar, Mohammad Alizadeh, David Mazières, Balaji Prabhakar, Albert Greenberg,
and Changhoon Kim
USENIX Symposium on Networked Systems Design and Implementation (NSDI), Mar 2013 [slides & video]
Sharing the Data Center Network
Alan Shieh, Srikanth Kandula, Albert G Greenberg, Changhoon Kim, and Bikas Saha
USENIX Symposium on Networked Systems Design and Implementation (NSDI), Mar 2011 [slides & video]
VL2: A Scalable and Flexible Data Center Network
Albert Greenberg, James R Hamilton, Navendu Jain, Srikanth Kandula, Changhoon Kim, Parantap Lahiri,
David A Maltz, Parveen Patel, and Sudipta Sengupta
ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2009 [video]
ACM Test of Time Award 2019
Floodless in Seattle: A Scalable Ethernet Architecture for Large Enterprises
Changhoon Kim, Matthew Caesar, and Jennifer Rexford
ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2008