Transactions as the Foundation of a Memory Consistency Model

We argue that traditional synchronization objects, such as locks, conditions, and atomic/volatile variables, should be defined in terms of transactions, rather than the other way around. A traditional critical section, in particular, is a region of code, bracketed by transactions, in which certain data have been privatized. We base our memory model on the notion of strict serializability (SS), and show that selective relaxation of the relationship between program order and transaction order can allow the implementation of transaction-based locks to be as efficient as conventional locks. We also show that condition synchronization can be accommodated without explicit mention of speculation, opacity, or aborted transactions. Finally, we compare SS to the notion of strong isolation (SI), arguing that SI is neither sufficient for transactional sequential consistency (TSC) nor necessary in programs that are transactional data-race free (TDRF).

• Type: Journal
• Year: 2010
• Where: WDAG
• Authors: Luke Dalessandro, Michael L. Scott, Michael F. Spear
• Keywords: Algorithms, Locks, Traditional Critical Section, Transactional Sequential Consistency, WDAG 2010