Y. Charlie Hu
Michael and Katherine Birck Professor of Electrical and Computer Engineering
Professor of Computer Science (by courtesy)
IEEE Fellow
Systems and Networking Group
Purdue University
(See also the official home page)
Address: Purdue University, School of ECE, EE Building, 465 Northwestern Ave., West Lafayette, Indiana 47907-2035
Phone: 765-494-9143
Secretary: Gabby Canine, 494-3558

Links: Google Scholar, 15 Rep. Papers, Press, Software Release, Awards, Talks, Ph.D. Graduates, Publications (by date  by type), Patents


Y. Charlie Hu's research interests are in Mobile Systems, Distributed Systems, Operating Systems, and Computer Networks.

He is an ACM Distinguished Scientist and an IEEE Fellow. He received his Ph.D. in Computer Science from Harvard in 1997. He is a recipient of the Honda Initiation Grant Award, NSF CAREER Award, Purdue University College of Engineering Early Career Research Award in 2009, Purdue University Faculty Scholar (2011-2016), and EuroSys Best Student Paper Award in 2012. He has served as a General Co-Chair of ACM SIGCOMM 2014, and Program Committee Co-Chair of ACM MobiCom 2016 and ACM SIGOPS EuroSys 2018. Since 2010, his research group has conducted ground-breaking work on energy profiling and energy debugging on smartphones which has been widely covered by over 500 news media such as ABC News, NBC News, BBC, Times of India, MIT Tech Review, and Scientific American. The technology has been commercialized and is extending the battery life of hundreds of millions of smartphones.

Selected Publications

Machine Learning at the Edge
Do Larger (More Accurate) DNN Models Help in Edge-Assisted AR? (SIGCOMM NAI 2021)
AQuA: Analytical Quality Assessment for Optimizing Video Analytics Systems (Symp. Edge Computing 2021)

VR/AR, 5G, and Edge Computing
An Analysis of End-to-End Delay in 360-degree Live Video Streaming (ACM Multimedia 2020)
Coterie: Exploiting Frame Similarity to Enable High-Quality Multiplayer VR on Commodity Mobile Devices (ASPLOS 2020)
How to Evaluate Mobile 360-degree Video Streaming Systems? (HotMobile 2020)
Mobility Support in Cellular Networks: A Measurement Study on Its Configurations and Implications (IMC 2018)
Furion: Engineering High-Quality Immersive Virtual Reality on Today's Mobile Devices (MobiCom 2017) (150 cites Google Scholar)

Energy Profiling, Debugging, and Analytics: The Foundation of AEM (App Energy Management)
Experience: Developing a Usable Battery Testing and Diagnostic Tool for the Mobile Industry (ACM MobiCom 2021)
Proactive Energy-Aware Adaptive Video Streaming on Mobile Devices (USENIX ATC 2021)
How much battery does dark mode save? An Accurate OLED Display Power Profiler for Modern Smartphones (MobiSys 2021) (press)
Why is my app draining more battery? Energy Optimization via Diffing Similar Apps (OSDI 2018)
A Fine-grained Event-based Modem Power Model for Enabling In-depth Modem Energy Drain Analysis (Sigmetrics 2018)
GfxDoctor: A Holistic Graphics Energy Profiler for Mobile Devices (EuroSys 2017)
Unsafe Time Handling in Smartphones (USENIX ATC 2016)
Smartphone Background Activities in the Wild: Origin, Analysis and Optimization (MobiCom 2015) (read BBC and Internet-wide media coverage 99 cites Google Scholar)
Smartphone Energy Drain in the Wild: Analysis and Implications (Sigmetrics 2015) (Podcast by Scientific American) (120 cites in Google Scholar)
Energy and Performance of Smartphone Radio Bundling in Outdoor Environments (WWW 2015)
On Death, Taxes, and Sleep Disorder Bugs in Smartphones (HotPower 2013)
How Much Energy Can We Save from Prefetching Ads? Energy Drain Analysis of Top 100 Apps (HotPower 2013)
Hypnos: Understanding and Treating Sleep Conflicts in Smartphones (EuroSys 2013) (40 cites)
Characterizing and Modeling the Impact of Wireless Signal Strength on Smartphone Battery Drain (Sigmetrics 2013) (240 cites in Google Scholar)
What is keeping my phone awake? Characterizing and Detecting No-Sleep Energy Bugs in Smartphone Apps (MobiSys 2012) (340 cites in Google Scholar)
Where is the energy spent inside my app? Fine Grained Energy Accounting on Smartphones with Eprof (EuroSys 2012, Best Student Paper Award) (850 cites in Google Scholar)
Fine-Grained Power Modeling for Smartphones Using System Call Tracing (EuroSys 2011) (450 cites in Google Scholar)
Bootstrapping Energy Debugging on Smartphones: A First Look at Energy Bugs in Mobile Devices (HotNets 2011) (280 cites in Google Scholar)

Data Center Networking, Cloud Computing
A Case for Task Sampling based Learning for Cluster Job Scheduling (NSDI 2022)
Your Coflow has Many Flows: Sampling Them for Fun and Speed (USENIX ATC 2019)
Saath: Speeding up CoFlows by Exploiting the Spatial Dimension (CoNEXT 2017)
Cloud-scale Load Balancer - Episode III: Yoda: A highly available layer-7 load balancer (EuroSys 2016)
Cloud-scale Load Balancer - Episode II: Unlocking the Power of Locality and End-point Flexibility in Cloud Scale Load Balancer (USENIX ATC 2015)
Cloud-scale Load Balancer - Episode I: Duet: Cloud Scale Load Balancing with Hardware and Software (SIGCOMM 2014) (190 cites)
On the impact of packet spraying in data center networks (INFOCOM 2013) (200 cites)
The Only Constant is Change: Incorporating Time Varying Network Reservations in Data Centers (SIGCOMM 2012) (300 cites in Google Scholar)
The TCP Outcast Problem: Exposing Unfairness in Data Center Networks (NSDI 2012) (80 cites)
On the Efficacy of Fine-Grained Traffic Splitting Protocols in Data Center Networks (Sigmetrics 2012 Ext. Abs.)
Latency Inflation with MPLS-based Traffic Engineering (IMC 2011)
Optimizing Cost and Performance in Online Service Provider Networks (NSDI 2010) (140 cites in Google Scholar)

Operating Systems / Buffer Cache Management:
The Performance Impact of Kernel Prefetching on Buffer Cache Replacement Algorithms (SIGMETRICS 2005, IEEE TC 2007, Software Release) (150 cites in Google Scholar)
Program Counter Based Pattern Classification in Buffer Caching (OSDI 2004) (150 cites in Google Scholar)
Program Counter Based Prediction Techniques for Dynamic Power Management (HPCA 2004, IEEE TC 2006)

Wireless Networking:
Pacifier: High-Throughput, Reliable Multicast without "Crying Babies" in Wireless Mesh Networks. (ToN 2012, Software Release) (120 cites Google Scholar)
CCACK: Efficient Network Coding Based Opportunistic Routing through Cumulative Coded Acknowledgments (ToN 2011) (200 cites Google Scholar)
Context Based Routing: Technique, Applications and Experience (NSDI 2008)
How to evaluate exotic wireless routing protocols? (HotNets 2008)
TDM MAC Protocol Design and Implementation for Wireless Mesh Networks (CoNEXT 2008)
Practical Service Provisioning for Wireless Meshes (CoNEXT 2007)

How to Improve Your Google Ranking: Myths and Reality (WI 2010, press: InfoExec, JH Web, SpoonyLife, 1 of 7 favorite papers of Human Factors International 2014)
Botnet Spam Campaigns can be Long Lasting: Evidence, Implications, and Analysis (SIGMETRICS 2009)
iSPY: Detecting IP Prefix Hijacking on My Own (SIGCOMM 2008, ToN 2010) (200 cites in Google Scholar)
Practical Defenses Against BGP Prefix Hijacking (CoNEXT 2007)
Understanding Network Delay Changes Caused by Routing Events (SIGMETRICS 2007)
On the Impact of Research Network Based Testbeds on Wide-area Experiments (IMC 2006)

Exploiting the Synergy between Peer-to-Peer and Mobile Ad Hoc Networks (HotOS 2003) (150 cites in Google Scholar)
Runtime Support for Distributed Sharing in Safe Languages (ACM TOCS 2003)

Selected Recent Projects:

Software Releases


Research in our group has been supported by

Ph.D Students

Note to applicants

Past Postdoc

Ph.D. and M.S. Graduates (18 + 3)


ECE 695 Introduction to Operating Systems (Fall 2021, 2020)
ECE 595 Introduction to Operating Systems (Fall 2019, 2018, Spring 2017)
ECE 469 Operating Systems Engineering (Spring 2015, 2014, 2013, 2011-2009, 2007-2005, 2003, 2002)
ECE 673 Distributed Computing Systems (Spring 2020, 2019, Fall 2016, 2014, 2012, 2011, 2010, 2007-2002)
ECE Wireless Networking Seminar (Spring 2011)
ECE Wireless Networking Seminar (Fall 2010)

Professional activities


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