Design and implementation of transactional constructs for C/C++

Abstract

This paper presents a software transactional memory system that introduces first-class C++ language constructs for transactional programming. We describe new C++ language extensions, a production-quality optimizing C++ compiler that translates and optimizes these extensions, and a highperformance STM runtime library. The transactional language constructs support C++ language features including classes, inheritance, virtual functions, exception handling, and templates. The compiler automatically instruments the program for transactional execution and optimizes TM overheads. The runtime library implements multiple execution modes and implements a novel STM algorithm that supports both optimistic and pessimistic concurrency control. The runtime switches a transaction's execution mode dynamically to improve performance and to handle calls to precompiled functions and I/O libraries. We present experimental results on 8 cores (two quad-core CPUs) running a set of 20 non-trivial parallel programs. Our measurements show that our system scales well as the numbers of cores increases and that our compiler and runtime optimizations improve scalability.

Adaptive locks: Combining transactions and locks for efficient concurrency

“…Additionally, the issue of contention management [47][48][49] is closely related to adaptive mode switching. A contention manager decides on a policy for favoring transactions in the case of contention, possibly radically switching the performance characteristics of the system.…”

“…A contention manager decides on a policy for favoring transactions in the case of contention, possibly radically switching the performance characteristics of the system. A close relative of adaptive locks in this space is the work of Ni et al [48], which describes a real-world implementation of transactional constructs for C and C++. Their approach includes multiple mechanisms that are related to switching implementation policy, including transactions that can perform irrevocable operations, transactions that put all other transactions on hold, and switching a transaction between optimistic and pessimistic concurrency control.…”

Atomic quake

“…STAMP does not provide lock based implementations of the applications, although the behavior of variants using a single global lock, in place of transactions, has sometimes been studied [1]. SPLASH-2 [35] is a suite of highly parallel applications which have subsequently been adapted to use TM for synchronization [25]. In general, the SPLASH-2 applications involve short, infrequent, critical sections.…”

LV^∗: A low complexity lazy versioning HTM infrastructure

“…Software transactional memory is a relatively mature field and some embodiments have been deployed in productionquality compilers [18]. While they provide a framework for gaining experience working with transactions, the loss in performance is too big to attract a reasonable user community [3].…”