Practical weak-atomicity semantics for java stm

Abstract

As memory transactions have been proposed as a language-level replacement for locks, there is growing need for well-defined semantics. In contrast to database transactions, transaction memory (TM) semantics are complicated by the fact that programs may access the same memory locations both inside and outside transactions. Strongly atomic semantics, where non transactional accesses are treated as implicit single-operation transactions, remain difficult to provide without specialized hardware support or significant performance overhead. As an alternative, many in the community have informally proposed that a single global lock semantics [18,10], where transaction semantics are mapped to those of regions protected by a single global lock, provide an intuitive and efficiently implementable model for programmers.