Subtleties of Transactional Memory Atomicity Semantics

Abstract-- Transactional memory has great potential for simplifying multithreaded programming by allowing programmers to specify regions of the program that must appear to execute atomically. Transactional memory implementations then optimistically execute these transactions concurrently to obtain high performance. This work shows that the same atomic guarantees that give transactions their power also have unexpected and potentially serious negative effects on programs that were written assuming narrower scopes of atomicity. We make four contributions: (1) we show that a direct translation of lock-based critical sections into transactions can introduce deadlock into otherwise correct programs, (2) we introduce the terms strong atomicity and weak atomicity to describe the interaction of transactional and non-transactional code, (3) we show that code that is correct under weak atomicity can deadlock under strong atomicity, and (4) we demonstrate that sequentially composing transactional ...

• Type: Journal
• Year: 2006
• Where: CAL
• Authors: Milo M. K. Martin, Colin Blundell, E. Lewis
• Keywords: CAL 2006, CAL 2008, Strong Atomicity, Transactional Memory, Weak Atomicity