WOMM: A Weak Operational Memory Model

Abstract. Memory models of shared memory concurrent programs define the values a read of a shared memory location is allowed to see. Such memory models are typically weaker than the intuitive sequential consistency semantics to allow efficient execution. In this paper, we present WOMM (abbreviation for Weak Operational Memory Model) that formally unifies two sources of weak behavior in hardware memory models: reordering of instructions and weakly consistent memory. We show that a large number of optimizations are allowed by WOMM. We also show that WOMM is weaker than a number of hardware memory models. Consequently, if a program behaves correctly under WOMM, it will be correct with respect to those hardware memory models. Hence, WOMM can be a formally specified abstraction of the hardware memory models. Moreover, unlike most weak memory models, WOMM is described using operational semantics, making it easy to integrate into a model checker for concurrent programs. We further show tha...

• Type: Journal
• Year: 2010
• Where: ISOLA
• Authors: Arnab De, Abhik Roychoudhury, Deepak D'Souza
• Keywords: Formal Methods, Hardware Memory Models, ISOLA 2010, Memory Models, Sequential Consistency Semantics