Victor Luchangco

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We describe DSTM2, a Java&#8482; software library that provides a flexible framework for implementing object-based software transactional memory (STM). The library uses <i>transactional factories</i> to transform sequential (unsynchronized) classes into atomic (transactionally synchronized) ones, providing a substantial improvement over the awkward(More)
Transactional memory (TM) promises to substantially reduce the difficulty of writing correct, efficient, and scalable concurrent programs. But "bounded" and "best-effort" hardware TM proposals impose unreasonable constraints on programmers, while more flexible software TM implementations are considered too slow. Proposals for supporting "unbounded"(More)
List-based implementations of sets are a fundamental building block of many concurrent algorithms. A skiplist based on the lock-free list-based set algorithm of Michael will be included in the Java Concurrency Package of JDK 1.6.0. However, Michael’s lock-free algorithm has several drawbacks, most notably that it requires all list traversal operations,(More)
We introduce obstruction-freedom, a new nonblocking property for shared data structure implementations. This property is strong enough to avoid the problems associated with locks, but it is weaker than previous nonblocking properties—specifically lock-freedom and wait-freedom— allowing greater flexibility in the design of efficient implementations.(More)
We present a new speci cation for distributed data services that trade-o immediate consistency guarantees for improved system availability and e ciency, while ensuring the long-term consistency of the data. An eventually-serializable data service maintains the operations requested in a partial order that gravitates over time towards a total order. It(More)
Over the last decade, great progress has been made in developing practical transactional memory (TM) implementations, but relatively little attention has been paid to precisely specifying what it means for them to be correct, or formally proving that they are. In this paper, we present TMS1 (Transactional Memory Specification 1), a precise specification of(More)
We describe a semi-automated verification of a slightly optimised version of Michael and Scott’s lock-free FIFO queue implementation. We verify the algorithm with a simulation proof consisting of two stages: a forward simulation from an automaton modelling the algorithm to an intermediate automaton, and a backward simulation from the intermediate automaton(More)
We define the Repeat Offender Problem (ROP). Elsewhere, we have presented the first dynamic-sized, lock-free data structures that can free memory to any standard memory allocator—even after thread failures—without requiring special support from the operating system, the memory allocator, or the hardware. These results depend on a solution to the ROP(More)