A Closer Look at Detectable Objects for Persistent Memory

Abstract

Research on multi-core algorithms is adapting rapidly to the new opportunities and challenges posed by persistent memory. One of these challenges is the fundamental problem of formalizing the behaviour of concurrent objects in the presence of crash failures, and giving precise meaning to the semantics of recovery from such failures. Li and Golab (DISC'21) recently proposed a sequential specification for such recoverable objects, called the detectable sequential specification or DSS. Building on their work, we explore examples of how DSS-based objects can be used by a sample application, and examine more closely the division of labour between the application's environment, the application code, and the recoverable object used by the application. We also propose an alternative formal definition of correctness, called the unified detectable sequential specification (UDSS), that simplifies both the object's interface and the application code. Using a black box transformation, we show how a UDSS-based object can be implemented from one that conforms to Li and Golab's specification. Finally, we present experiments conducted using Intel Optane persistent memory to quantify the performance overhead of our transformation.