Software thread-level speculation: an optimistic library implementation

Software thread level speculation (tls) solutions tend to mirror the hardware ones, in the sense that they employ one, exact dependency-tracking mechanism. Our perspective is that software-flexibility is, perhaps, better exploited by a family of lighter, if less precise speculative models that can be combined together in an effective configuration, which takes advantage of the application’s code-patterns. This paper reports on two main contributions. First, it introduces splsc: a software tls model that trades the potential for false-positive violations for a small memory overhead and efficient implementation. Second, it presents PolyLibTLS: a library that encapsulates several lightweight models and enables their composition. In this context, we report on the template meta-programming techniques that we used to achieve performance and safety, while preserving library’s modularity, extensibility and usability properties. Furthermore, we demonstrate that the user-framework in-teraction is straightforward and present parallelization tim-ing results that validate our high-level perspective