Cornell Systems Lunch

CS 7490 Fall 2016
Friday 12PM, Gates 114

Robbert van Renesse

Sponsored by VMware

The Systems Lunch is a seminar for discussing recent, interesting papers in the systems area, broadly defined to span operating systems, distributed systems, networking, architecture, databases, and programming languages. The goal is to foster technical discussions among the Cornell systems research community. We meet once a week on Fridays at noon in Gates 114.

The systems lunch is open to all Cornell Ph.D. students interested in systems. First-year graduate students are especially welcome. Non-Ph.D. students have to obtain permission from the instructor. Student participants are expected to sign up for CS 7490, Systems Research Seminar, for one credit.

To join the systems lunch mailing list please send an empty message to with the subject line "join". More detailed instructions can be found here.

Links to papers and abstracts below are unlikely to work outside the Cornell CS firewall. If you have trouble viewing them, this is the likely cause.

Date Paper Presenter
August 26 Sieve: Cryptographically Enforced Access Control for User Data in Untrusted Clouds
Frank Wang, MIT CSAIL; James Mickens, Harvard University; Nickolai Zeldovich and Vinod Vaikuntanathan, MIT CSAIL
NSDI 2016
Soumya Basu
September 2 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
Shrutarshi Basu
September 9 A Secure Sharding Protocol For Open Blockchains
Loi Luu, Viswesh Narayanan, Chaodong Zheng, Kunal Baweja, Seth Gilbert and Prateek Saxena (National University of Singapore)
CCS 2016
Kevin Sekniqi
September 16 TicToc: Time Traveling Optimistic Concurrency Control
Xiangyao Yu, Andrew Pavlo, Daniel Sanchez, and Srinivas Devadas
Natacha Crooks
September 23 Thoth: Comprehensive Policy Compliance in Data Retrieval Systems
Eslam Elnikety, Aastha Mehta, Anjo Vahldiek-Oberwagner, Deepak Garg, and Peter Druschel, Max Planck Institute for Software Systems (MPI-SWS)
USENIX Security 2016
Eleanor Birrell
September 30 Profiling in-memory caches dynamically

Large-scale in-memory object caches such as memcached are widely used to accelerate popular web sites and to reduce burden on backend databases. Yet operators still have limited visibility into how these caches should be set up to optimally accommodate the workloads at hand. How much would the cache performance improve from additional cache space, or by adding more cache servers to the pool? Resources come at a cost, so to what extent would user request latency deteriorate if cache memory is repurposed for a different service?

In this talk, I will focus on several research questions pertaining to large-scale distributed caches. In particular, I will home in on the challenge of providing online monitoring of the cost and benefits of memory space in a large-scale cache, enabling cache operators to answer these questions without requiring trace collection and manual offline tuning. In our work, we introduce general and efficient algorithms for dynamically estimating hit rate curves -- histograms of cache hit rate as a function of memory size -- which can be plugged into cache replacement policies such as LRU.

Extensive simulations on cache benchmarks indicate that our methods provide accurate estimates of hit rate at different cache sizes. Our experiments on an implementation of our methods in memcached showed that hit rate curves were dynamically estimated at over 98% accuracy with only a small drop in throughput. The results are encouraging and suggest that exposing hit rate curves can be a practical method for improving provisioning and metering of large-scale caches.

This is joint work with Trausti Saemundsson at CloudPhysics and Gregory Chockler at the University of London, Royal Holloway.

Bio: Ymir Vigfusson is Assistant Professor of Mathematics and Computer Science at Emory University since 2014, Assistant Professor at the School of Computer Science at Reykjavik University since 2011, and a co-founder and Chief Science Officer of the offensive security company Syndis since 2013. Ymir completed his Ph.D. in Computer Science at Cornell University (2010) with focus on Distributed Systems and minor in music composition, where his dissertation was nominated for the ACM Doctoral Dissertation Award. His primary research interests are on distributed data replication, data science and security. His work is partially supported by an NSF CAREER award, the CDC and grants from the Icelandic Center for Research, and his website is

Ymir Vigfusson
October 7 Safe Serializable Secure Scheduling: Transactions and the Trade-off Between Security and Consistency
Isaac Sheff, Tom Magrino, Jed Liu, Andrew C. Myers, and Robbert van Renesse
CCS 2016
Isaac Sheff
October 14 Programming and System Support for Reliable Intermittent Computing

Emerging energy-harvesting devices (EHDs) are computer systems that operate using energy extracted from their environment, even from low-power sources like ambient radio-frequency energy. Future EHDs will be a key enabler of emerging implantable medical devices, IoT applications, and nano-satellites, but todays EHDs operate intermittently, only as environmental energy is available. Unfortunately, intermittence makes todays EHDs unreliable and extremely difficult to program and debug. In this talk I will summarize the main challenges of intermittent execution. I will then discuss our recent efforts developing system, programming language, and toolchain support for EHDs to address the challenges of intermittence, focusing especially on programmability, debugging, and reliability. I will close by discussing our recent work on building a reliable, EHD-based, hardware/software application platform for an upcoming deployment.

Bio: Brandon Lucia is an assistant professor in the department of electrical and computer engineering at Carnegie Mellon University in Pittsburgh, PA. His research focuses on redefining computer architectures and systems that make increasingly pervasive, often safety-critical, devices reliable, energy-efficient, and programmable. Brandon and his lab are currently focusing on defining the system stack for systems with intermittently available energy and resources, as well as on redefining parallel architectures to improve their efficiency, correctness, and reliability, exploiting heterogeneity and approximation. His work targets the boundaries between computer architecture, compilers, system software, and programming languages. His research group is supported by the National Science Foundation, Google, Intel, and Disney Research. Brandon has received a Google Faculty Research Award, the Bell Labs Prize, an OOPSLA Distinguished Paper Award and an OOPSLA Distinguished Artifact Award, and Brandon was elected in 2016 to serve on DARPAs Information Science And Technology (ISAT) study group. Before joining CMU, Brandon spent a year as a Researcher at Microsoft Research, Redmond. Brandon earned a Ph.D. in Computer Science and Engineering from the University of Washington in 2013, and a B.S. degree in Computer Science from Tufts University. His personal website is, his research group is at, and his band netcat is at

Brandon Lucia
October 21 Breaking web applications built on top of encrypted data
Paul Grubbs (Cornell University), Richard McPherson (University of Texas, Austin), Muhammed Naveed (University of Southern California), Thomas Risenpart and Vitaly Shmatikov (Cornell Tech)
CCS 2016
Paul Grubbs
October 28 The Snowflake Elastic Data Warehouse
Benoit Dageville et al. (Snowflake)
Ashish Motivala
November 4 FaSST: Fast, Scalable and Simple Distributed Transactions with Two-sided (RDMA) Datagram RPCs
Anuj Kalia, Michael Kaminsky, and David G. Andersen (CMU, Intel Labs)
OSDI 2016
Edward Tremel
November 11 Datometry Hyper-Q: Bridging the Gap Between Real-Time and Historical Analytics
Lyublena Antova, Rhonda Baldwin, Derrick Bryant, Tuan Cao, Michael Duller, John Eshleman, Zhongxian Gu, Entong Shen, Mohamed A. Soliman, and F. Michael Waas (Datometry)
Tuan Cao
November 18 ACSU Luncheon—no systems lunch, no meeting.
November 25 Thanksgiving Break, no meeting.
December 2 Slicer: Auto-Sharding for Datacenter Applications
Adya A, Myers D, Howell J, Elson J, Meek C, Khemani V, Fulger S, Gu P, Bhuvanagiri L, Hunter J, Peon R, Kai L, Shraer A, Merchant A, and Lev-Ari K
OSDI 2016
Robert Escriva