The Scalable Synchronization Research Group (SSRG) is focused on principles and techniques for developing concurrent programs that are scalable, efficient, and correct.

We refer to scalability broadly, applying our expertise to a wide range of performance problems across various environments, from user and OS kernel code running on large multi-sockets machines with shared memory to distributed applications running on multiple computing nodes in the cloud. Our methods include novel (read-write, NUMA-aware, energy-efficient) lock implementations, efficient concurrent data structures, scalable memory allocation and management, etc. The results of our research have been published in premier conferences as well as got integrated into numerous Oracle products.

In addition, we are interested in exploring and understanding the fundamental ramifications of various hardware features (such as hardware transactional memory (HTM), non-volatile memory (NVM), remote direct memory access (RDMA) support, etc.) on the properties of synchronization algorithms and concurrent data structures. We also have strong expertise in the specification and verification of concurrent algorithms, which is important because the kinds of synchronization algorithms we use to improve the system performance are often intricate and subtle.

Mission

The Scalable Synchronization Research Group at Oracle Labs is exploring hardware and software mechansisms for facilitating the easy development of correct, efficient, and scalable concurrent programs. This goal is increasingly important as multicore computing becomes ubiquitous, and increasingly difficult as systems become larger. Since being acquired by Oracle in 2010, we have continued our research in these areas, and we are also exploring ways in which techniques developed by us and others may be successfully exploited in Oracle's products.

ALUMNI

• Pantea Zardorshti, intern (summer '17)
• Victor Miraldo, intern (summer '17)
• Isaac Sheff, intern (summer '16)
• Trevor Brown, intern (summer '15)
• Maya Arbel, intern (summer '15)
• Joe Izraelevitz, intern (summer '14)
• Justin Kopinsky, intern (summer '14)
• Tim Merrifield, intern (summer '13)
• Yujie Liu, intern (summer '12 - '13)
• Nir Shavit, full-time member (on and off for more than a decade), now at MIT
• Mohsen Lesani, intern (winter '12)
• Irina Calciu, intern (summer '11)
• Aleksandar Dragojevic, intern (summer '10)
• Yossi Lev, intern ('04 - '10)
• Dan Nussbaum, full-time member ('04 - '10)
• Marek Olszewski, extern (January '09), intern (summer '09)
• Kevin Moore, full-time member ('07 - '08)
• Alexandra Fedorova, intern ('03 - '06)
• Ori Shalev, intern ('04 - '06)
• Virendra J. Marathe, intern (summer '05)
• Simon Doherty, intern (summer '03)
• Bill Scherer, intern (summer '02)

• Generic Concurrency Restriction - slides for the Dagstuhl seminar
  Alex Kogan, Dagstuhl seminar on “New Challenges in Parallelism”

• Improving Parallelism in Hardware Transactional Memory
  Dave Dice, Maurice Herlihy, Alex Kogan, ACM Transactions on Architecture and Code Optimization (TACO)

• Malthusian Locks - slides for EuroSys 2017
  Dave Dice, EuroSys 2017

• Towards Understandable Smart Contracts
  Harold Carr, Davin Fifield, Chris Flemming, Mark Moir, Bill Xie, Slides for Symposium on Distributed Ledger Technology (SDLT2017), Griffiths University, Gold Coast, Australia, June 13, 2017.

• Transactional Lock Elision Meets Combining
  Alex Kogan, Yossi Lev, ACM Symposium on Principles of Distributed Computing (PODC)

• Fast non-intrusive memory reclamation for highly-concurrent data structures
  Dave Dice, Maurice Herlihy, Alex Kogan, ISMM 2016

• Investigating the Performance of Hardware Transactions on a Multi-Socket Machine
  Trevor Brown, Alex Kogan, Victor Luchangco, Yossi Lev, SPAA 2016

• Malthusian Locks
  Dave Dice, PPoPP 2017

• Primus Inter Pares: Improving Parallelism in Hardware Transactional Memory
  Dave Dice, Maurice Herlihy, Alex Kogan, ACM/IEEE International Symposium on Computer Architecture (ISCA)

• The Influence of Malloc Placement on TSX Hardware Transactional Memory.
  Dave Dice, Tim Harris, Alex Kogan, Yossi Lev, CoRR abs/1504.04640 (2015)

• Adaptive Integration of Hardware and Software Lock Elision Techniques.
  Dave Dice, Alex Kogan, Yossi Lev, Timothy Merrifield, Mark Moir, SPAA 2014

• Hardware extensions to make lazy subscription safe
  Dave Dice, Tim Harris, Alex Kogan, Yossi Lev, Mark Moir, Extended version of our WTTM 2014 paper.

• Pitfalls of lazy subscription
  Dave Dice, Tim Harris, Alex Kogan, Yossi Lev, Mark Moir, 6th Workshop on the Theory of Transactional Memory (WTTM 2014)

• The Future(s) of Shared Data Structures.
  Alex Kogan, Maurice Herlihy, PODC 2014

• Constrained Data-Driven Parallelism
  Tim Harris, Yossi Lev, Victor Luchangco, Virendra Marathe, Mark Moir, In Proceedings, (2013)

• Formal Machine-Checked Verification of a Real Transactional Memory Algorithm
  Victor Luchangco, Slides, (2011)

• On The Power of Hardware Transactional Memory to Simplify Memory Management
  Aleksandar Dragojevic, Maurice Herlihy, Yossi Lev, Mark Moir, Conference Publication, (2011)

• Revisiting Condition Variables and Transactions
  Victor Luchangco, Virendra Marathe, In Proceedings, (2011)

• Towards Formally Specifying and Verifying Transactional Memory
  Simon Doherty, Lindsay Groves, Victor Luchangco, Mark Moir, Article, (2011)

• You Are Not Alone: Breaking Transaction Isolation
  Victor Luchangco, Virendra Marathe, In Proceedings, (2010)

• Anatomy of a Scalable Software Transactional Memory
  Yossi Lev, Victor Luchangco, Marek Olszewski, Virendra Marathe, Mark Moir, Dan Nussbaum, In Proceedings, (2009)

• Early Experience with a Commercial Hardware Transactional Memory Implementation
  David Dice, Yossi Lev, Mark Moir, Daniel Nussbaum, Marek Olszewski, Technical Report, (2009)

• Exceptions and Transactions in C++
  Adam Welc, Ali-Reza Adl-Tabatabai, Mark Moir, Mark Moir, Ravi Narayanaswamy, Victor Luchangco, Victor Luchangco, Xinmin Tian, Yang Ni, In Proceedings, (2009)

• Exceptions and Transactions in C++
  Adam Welc, Ali-Reza Adl-Tabatabai, Dan Nussbaum, Mark Moir, Peng Wu, Ravi Narayanaswamy, Victor Luchangco, Virendra Marathe, Xinmin Tian, Yang Ni, In Proceedings, (2009)

• Capabilities and Limitations of Library-Based Software Transactional Memory in C++
  Luke Dalessandro, Virendra Marathe, Michael Spear, Michael Scott, In Proceedings, (2007)

• Delaunay Triangulation with Transactions and Barriers
  Michael Scott, Michael Spear, Luke Dalessandro, Virendra Marathe, In Proceedings, (2007)

• Hardware Acceleration of Software Transactional Memory
  Arrvindh Shriraman, Virendra Marathe, Sandhya Dwarkadas, Michael Scott, David Eisenstat, Christopher Heriot, William Scherer III, Michael Spear, In Proceedings, (2006)

• Lowering the Overhead of Nonblocking Software Transactional Memory
  Virendra Marathe, Michael Spear, Christopher Heriot, Athul Acharya, David Eisenstat, William Scherer III, Michael Scott, In Proceedings, (2006)

• Dynamic-Sized Nonblocking Work Stealing Deque, A
  Danny Hendler, Yossi Lev, Mark Moir, Nir Shavit, Technical Report, (2005)

• Transaction Synchronizers
  Victor Luchangco, In Proceedings, (2005)

• Using LL/SC to SimplifyWord-based Software Transactional Memory
  Virendra Marathe, Michael Scott, In Proceedings, (2005)

• Design Tradeoffs in Modern Software Transactional Memory Systems
  Virendra Marathe, William Scherer III, Michael Scott, In Proceedings, (2004)

• Supporting Per-processor Local-allocation Buffers Using Multi-processor Restartable Critical Sections
  Derek White, David Dice, Alex Garthwaite, Technical Report, (2004)

• DCAS-based Concurrent Deques Supporting Bulk Allocation
  Mark Moir, Guy Steele, Paul Martin, Technical Report, (2002)

• Dynamic-sized Lockfree Data Structures
  Victor Luchangco, Paul Martin, Mark Moir, Maurice Herlihy, Technical Report, (2002)

• Repeat Offender Problem: A Mechanism for Supporting Dynamic-sized Lock-free Data Structures, The
  Maurice Herlihy, Victor Luchangco, Mark Moir, Technical Report, (2002)

• Lock-Free Transactions for Real-Time Systems.
  James Anderson, Srikanth Ramamurthy, Mark Moir, Kevin Jeffay, RTDB 1996:103-110