Christopher Small

70 Chilton Street, Cambridge, MA 02138

(617) 945-6961

christopher.small@gmail.com

https://goo.gl/DjNgPG

Professional Experience

Google (2017—)        Cambridge, MA

2022—present: Software Engineer/tech lead on Google Cloud team responsible for configuration and telemetry of wide-area networking hardware.

2017—2022: Software Engineer/tech lead on Flights Availability team, responsible for a back-end service providing up-to-date per-flight booking information for hundreds of airlines and millions of flights, supporting Google Flight Search and the websites of several major carriers.

Facebook (2015—2017)        Cambridge, MA

Software Engineer

Member of Core Data, the organization responsible for storing and serving Facebook’s Social Graph. Developed an update pipeline that cut the tail (p99) latency of in-region updates to secondary caches (storing materialized views) by an order of magnitude, which reduced the user-visible window of inconsistency between the two, especially when cross-region replication lagged.

Philo (formerly Tivli) (2013—2015)        Cambridge, MA

Principal Member of Technical Staff

Responsible for back-end infrastructure engineering, customer support, and managing new deployments for the Philo IPTV platform.

Quanta Research Cambridge (2012—2013)        Cambridge, MA

Senior Member of Technical Staff.

Contributed to the design and development of a cloud-based service for Eulerian Video Magnification, a technique developed by Quanta and MIT researchers that magnified small periodic motions. Completed implementation, debugged, and supported the cloud service. Handled a jump from 10 visitors a day to 10,000 when the site was discussed in the New York Times. Developed a proof-of-concept cloud-based digital animation service that used Dropbox for transparent mirroring between the user’s machines and the cloud-based service, and web UI for monitoring progress and previewing results.

NetApp (2009—2012)        Waltham, MA

Senior Engineer, Advanced Technology Group.

Tech lead of Project Mercury, a portable host disk cache for virtual machine monitors. Transferred the project to production (NetApp Flash Accel). Responsible for design and development of the  core multithreaded deduplicating block cache. Designed and implemented a novel adaptive trie-based data structure for storing inverse block mapping, greatly reducing client RAM use in the common case.

BBN Technologies (2005—2009)        Cambridge, MA

Senior Scientist, Networking Research.

2008—2009: GENI Project Office: Senior Systems Engineer. Oversaw planning of GENI. Worked with research community to identify system requirements, develop system architecture, define cross-project interfaces, evaluate proposals, and oversee prototyping efforts by academic groups.

2006—2008: SPINDLE: DARPA Disruption Tolerant Networking (DTN) program ($8.9M contract). Phase III: PI. Led team of sixteen engineers. Responsible for working with customer (DARPA), and evangelizing technology to transition partners. Phase III focused on developing robust and scalable technology and transitioning it into fielded military communication systems. Phase II: systems tech lead. Led staff of twelve engineers debugging, re-architecting, testing, hardening, extending, and integrating IRTF DTN Research Group reference implementation of DTN. Demonstrated system in live field tests.

2005-2006: RAMCAP: project member. RAMCAP developed special-purpose hardware for forensic capture of RAM of a running computer system. Brought up kernel (Linux 2.4 on PPC) on flaky hardware, wrote device drivers, etc.

Sun Microsystems (2000—2005)        Burlington, MA

2001—2005: Principal Investigator, Sun Labs. Led group of five investigating how best to take advantage of chip multiprocessor and vertically multithreaded systems. Four patents awarded.

2000—2001: Network Storage Technology Office. Research in scalable distributed storage.

Bell Laboratories, Lucent Technologies (1998-2000)        Murray Hill, NJ

Principal Investigator, Information Sciences Research Center. Research in operating systems, collaborative web searching, and file system modeling. Helped design and develop Pebble, a microkernel OS that generated specialized code for individual IPC paths at run-time. Patent awarded.

Siemens-Nixdorf (1991-1993)        Cambridge, MA

Technical lead of six-person Multimedia Group. Developed multimedia email system for Unix (pre-MIME). Architect of network-based multimedia resource allocator. Taught C++ classes to staff.

Beyond Inc. (1989-1991)        Cambridge, MA

Project lead for message transport and message database for email/groupware application.

ON Technology (1988-1989)        Cambridge, MA

Designed class system for ON Object Environment. Initiated ON Location, ON’s first product.

Ontologic (1985-1988)        Billerica, MA

Worked on compiler, browser, dynamic linker for first commercially available object-oriented DBMS.

Bell Laboratories, AT&T (1984-1985)        North Andover, MA

Language Tools Group. Wrote optimizer for C compiler, link editor for 8051.

Education

Harvard University (1993—1998)        Cambridge, MA

M.S., Ph.D. Computer Science.

Thesis: Building an Extensible Operating System. (Advisor: Dr. Margo Seltzer)

Boston University (1980—1984)        Boston, MA

B.A. Mathematics (magna cum laude), M.A. Computer Science.

Patents

• Operating system transfer of control and parameter manipulation using portals (6,604,123).
• Cache-aware scheduling for a chip multithreading processor (7,487,317; 7,818,747).
• Thread scheduling in chip multithreading processors (8,490,101; 8,539,491).
• Specializing I/O access patterns for flash storage (9,645,917).
• Method and apparatus for video compression of multiple instances using index frames (9,997,201).

Professional Activities 

• Senior member of the ACM and IEEE, member of USENIX.
• Program Chair, USENIX Annual Technical Conference (2000).
• Program Committee Member, USENIX Annual Technical Conference (1996, 1999, 2000, 2002, 2012, 2013), Conf. on Object Oriented Technologies and Systems (2001), HotOS (2005).
• Member, Steering Committee, Research Exchange Programme (USENIX/Stichting Nlnet).
• Reviewer, ACM Computing Surveys, ACM TOCS, PODC (2004), USENIX ATC (1994, 1995, 1997, 2001), OSDI (1994, 1996), SOSP (1999, 2001), FAST (2002), Computer Communications, MILCOM (2007), EuroSys (2009).
• CD-ROM Chair,  Symposium on Operating Systems Principles (1999, 2001).

Refereed Publications

• Steve Byan, James Lentini, Anshul Madan, Luis Pabón, Michael Condict, Jeff Kimmel, Steve Kleiman, Christopher Small, Mark Storer, “Mercury: Host-side Flash Caching for the Data Center,” 28th IEEE Conference on Massive Data Storage (MSST 2012), Pacific Grove, CA (2012).
• Rajesh Krishnan et al., “The SPINDLE Disruption-Tolerant Networking System,” IEEE MILCOM 2007, Orlando, FL.
• Yvonne Coady, Russ Cox, John DeTreville, Peter Druschel, Joseph Hellerstein, Andrew Hume, Kimberly Keeton, Thu Nguyen, Christopher Small, Lex Stein, Andrew Warfield, “Falling Off the Cliff: When Systems Go Nonlinear,” HotOS X, Santa Fe, NM (2005).
• Alexandra Fedorova, Margo I. Seltzer, Christopher Small, Daniel Nussbaum, “Performance of Chip Multithreading Processor and Implications for Operating System Design,” 2005 USENIX Annual Technical Conference, Anaheim, CA.
• Alexandra Fedorova, Christopher Small, Daniel Nussbaum, Margo I. Seltzer, “Chip Multithreading Systems Need a New Operating System Scheduler,” 2004 SIGOPS European Workshop.
• Eran Gabber, Christopher Small, John Bruno, José Brustoloni, Avi Silberschatz, “The Pebble Component-Based Operating System,” 1999 USENIX Annual Technical Conference, Monterey CA.
• Elizabeth Shriver, Christopher Small, Keith A. Smith, “Why Does File System Prefetching Work,” 1999 USENIX Annual Technical Conference, Monterey CA.
• John Bruno, José Brustoloni, Eran Gabber, Avi Silberschatz, Christopher Small, “Pebble: A Component- Based Operating System for Embedded Applications,” 1999 USENIX Workshop on Embedded Systems, Cambridge, MA.
• Christopher Small, Margo I. Seltzer, “MiSFIT: A Tool for Constructing Safe Extensible C++ Systems,” IEEE Concurrency 6, 3 (1998).
• Christopher Small, “A Tool for Constructing Safe Extensible C++ Systems,” Third USENIX Conference on Object-Oriented Technologies and Systems, Portland, OR (1997).
• Margo I. Seltzer, Christopher Small, “Self-Monitoring and Self-Adapting Operating Systems,” Sixth Workshop on Hot Topics in Operating Systems, Cape Cod, MA (1997).
• Christopher Small, Stephen Manley, “A Revisitation of Kernel Synchronization Schemes,” 1997 USENIX Technical Conference, Anaheim, CA.
• Margo I. Seltzer, Yasuhiro Endo, Christopher Small, Keith A. Smith, “Dealing with Disaster: Surviving Misbehaved Kernel Extensions,” Second Symposium on Operating Systems Design and Implementation, Seattle, WA (1996).
• Margo I. Seltzer, Christopher Small, Michael D. Smith, “Symbiotic Systems Software,” First Workshop on Compiler Support for Systems Software, Tucson, AZ (February 1996).
• Christopher Small, Margo I. Seltzer, “A Comparison of OS Extension Technologies,” 1996 USENIX Annual Technical Conference, San Diego, CA .
• Christopher Small, Margo I. Seltzer, “Structuring the Kernel as a Toolkit of Extensible, Reusable Components,” Fourth International Workshop on Object-Orientation in Operating Systems, Lund, Sweden (August 1995).

Unrefereed Publications 

• Daniel Nussbaum, Alexandra Fedorova and Christopher Small, “An overview of the Sam CMT simulator kit,” Sun Microsystems Laboratories Technical Report TR-2004-133.
• Margo I. Seltzer, Yasuhiro Endo, Christopher Small, and Keith A. Smith, “Issues in Extensible Operating Systems,'' Harvard University Computer Science Technical Report TR-18-97.
• Christopher Small, Narendra Ghosh, Hany Saleeb, Margo Seltzer, and Keith Smith, “Does Systems Research Measure Up?” Harvard University Computer Science Technical Report TR-16-97
• Christopher Small, “MiSFIT: A Freely Available Tool for Building Safe Extensible Systems,” Harvard University Computer Science Technical Report TR-07-96.
• Christopher Small and Margo I. Seltzer, “Scheduler Activations on BSD: Sharing Thread Management Between Kernel and Application, “ Harvard University Computer Science Technical Report TR-31-95.
• Margo I. Seltzer, Keith Smith, and Christopher Small. “The Case for Extensible Operating Systems,” Harvard University Computer Science Technical Report TR-16-95.
• Christopher Small and Margo I. Seltzer, “VINO: An Integrated Platform for Operating System and Database Research,” Harvard University Computer Science Technical Report TR-30-94.

Thesis: Building an Extensible Operating System 

When designing an extensible operating system, a developer must ensure that the operating system is protected from misbehaved extensions. Two kinds of protection are needed: first, extensions should not violate the operating system’s interface, and second, extensions should not be able to leave the operating system in an inconsistent state.

The major contributions of the thesis are (1) the design and evaluation of MiSFIT, a low-overhead software fault isolation tool for the x86 architecture that ensures that extensions do not violate the operating system’s interface; (2) the design and evaluation of VINO Lightweight Transactions, a low-overhead mechanism that allows the kernel to maintain its consistency in the face of ill-behaved extensions; (3) experiments that show the end-to-end overhead of MiSFIT and VLT protection is  low, on the order of 1-2%, and the net performance gain possible from using application-specific extensions  is significant, in some cases more than 20%; and (4) a cost-benefit framework for comparing extension technologies and an evaluation comparing commonly used extension technologies.