Transactional memory

About: Transactional memory is a research topic. Over the lifetime, 2365 publications have been published within this topic receiving 60818 citations.

Lock free data structures using STM in haskell

Abstract: This paper explores the feasibility of re-expressing concurrent algorithms with explicit locks in terms of lock free code written using Haskell's implementation of software transactional memory. Experimental results are presented which show that for multi-processor systems the simpler lock free implementations offer superior performance when compared to their corresponding lock based implementations.

Avoiding deadlock avoidance

Abstract: The evolution of processor architectures from single core designs with increasing clock frequencies to multi-core designs with relatively stable clock frequencies has fundamentally altered application design. Since application programmers can no longer rely on clock frequency increases to boost performance, over the last several years, there has been significant emphasis on application level threading to achieve performance gains. A core problem with concurrent programming using threads is the potential for deadlocks. Even well-written codes that spend an inordinate amount of effort in deadlock avoidance cannot always avoid deadlocks, particularly when the order of lock acquisitions is not known a priori. Furthermore, arbitrarily composing lock based codes may result in deadlock - one of the primary motivations for transactional memory. In this paper, we present a language independent runtime system called Sammati that provides automatic deadlock detection and recovery for threaded applications that use the POSIX threads (pthreads) interface - the de facto standard for UNIX systems. The runtime is implemented as a pre-loadable library and does not require either the application source code or recompiling/relinking phases, enabling its use for existing applications with arbitrary multi-threading models. Performance evaluation of the runtime with unmodified SPLASH, Phoenix and synthetic benchmark suites shows that it is scalable, with speedup comparable to baseline execution with modest memory overhead.

Identifying the Optimal Level of Parallelism in Transactional Memory Applications

Abstract: In this paper we investigate the issue of automatically identifying the "natural" degree of parallelism of an application using software transactional memory STM, i.e., the workload-specific multiprogramming level that maximizes application's performance. We discuss the importance of adapting the concurrency level to the workload in two different scenarios, a shared-memory and a distributed STM infrastructure. We propose and evaluate two alternative self-tuning methodologies, explicitly tailored for the considered scenarios. In shared-memory STM, we show that lightweight, black-box approaches relying solely on on-line exploration can be extremely effective. For distributed STMs, we introduce a novel hybrid approach that combines model-driven performance forecasting techniques and on-line exploration in order to take the best of the two techniques, namely enhancing robustness despite model's inaccuracies, and maximizing convergence speed towards optimum solutions.

A type system for data-centric synchronization

Abstract: Data-centric synchronization groups fields of objects into atomic sets to indicate theymust be updated atomically. Each atomic set has associated units of work, code fragments that preserve the consistency of that atomic set.We present a type system for data-centric synchronization that enables separate compilation and supports atomic sets that span multiple objects, thus allowing recursive data structures to be updated atomically. The type system supports full encapsulation for more efficient code generation. We evaluate our proposal using AJ, which extends the Java programming language with data-centric synchronization. We report on the implementation of a compiler and on refactoring classes from standard libraries and a multi-threaded benchmark to use atomic sets. Our results suggest that data-centric synchronization enjoys low annotation overhead while preventing high-level data races.

Program translation and transactional memory formation

Abstract: Disclosed are methods, machine readable medium and systems that dynamically translate binary programs. The dynamic binary translation may include identifying a hot code trace of a program. The translation may further include determining a completion ratio for the hot code trace. The translation may also include packaging the hot code trace into a transactional memory region in response to the completion ratio having a predetermined relationship to a threshold ratio.