Transactional Memory Today

The term "Transactional Memory" was coined back in 1993, but even today, there is a vigorous debate about what it means and what it should do. This debate sometimes generates more heat. than light: terms are not always well-defined and criteria for making judgments are not always clear. This article will try to impose some order on the conversation. TM itself can encompass hardware, software, speculative lock elision, and other mechanisms. The benefits sought encompass simpler implementations of highly-concurrent data structures, better software engineering for concurrent platforms and enhanced performance.