Total Store Order Memory Model Research Articles

A verified durable transactional mutex lock for persistent x86-TSO

AbstractThe advent of non-volatile memory technologies has spurred intensive research interest in correctness and programmability. This paper addresses both by developing and verifying a durable (aka persistent) transactional memory (TM) algorithm, $$\text {dTML}_{\text {Px86}}$$ dTML Px86 . Correctness of $$\text {dTML}_{\text {Px86}}$$ dTML Px86 is judged in terms of durable opacity, which ensures both failure atomicity (ensuring memory consistency after a crash) and opacity (ensuring thread safety). We assume a realistic execution model, Px86, which represents Intel’s persistent memory model and extends the Total Store Order memory model with instructions that control persistency. Our TM algorithm, $$\text {dTML}_{\text {Px86}}$$ dTML Px86 , is an adaptation of an existing software transactional mutex lock, but with additional synchronisation mechanisms to cope with Px86. Our correctness proof is operational and comprises two distinct types of proofs: (1) proofs of invariants of $$\text {dTML}_{\text {Px86}}$$ dTML Px86 and (2) a proof of refinement against an operational specification that guarantees durable opacity. To achieve (1), we build on recent Owicki–Gries logics for Px86, and for (2) we use a simulation-based proof technique, which, as far as we are aware, is the first application of simulation-based proofs for Px86 programs. Our entire development has been mechanised in the Isabelle/HOL proof assistant.

Trace Semantics and Algebraic Laws for Total Store Order Memory Model

Trace Semantics and Algebraic Laws for Total Store Order Memory Model

What is decidable under the TSO memory model?

We consider the verification problem of safety and liveness properties of finite-state programs running under the Total Store Ordering (TSO) memory model.We first review the decidability/complexity results regarding these two problems and then show that the termination problem is decidable.

TSO-to-TSO linearizability is undecidable

TSO-to-TSO linearizability is a variant of linearizability for concurrent libraries on the total store order (TSO) memory model. It is proved in this paper that TSO-to-TSO linearizability for a bounded number of processes is undecidable. We first show that the trace inclusion problem of a classic-lossy single-channel system, which is known undecidable, can be reduced to the history inclusion problem of specific libraries on the TSO memory model. Based on the equivalence between history inclusion and extended history inclusion for these libraries, we then prove that the extended history inclusion problem of libraries is undecidable on the TSO memory model. By means of extended history inclusion as an equivalent characterization of TSO-to-TSO linearizability, we finally prove that TSO-to-TSO linearizability is undecidable for a bounded number of processes. Additionally, we prove that all variants of history inclusion problems are undecidable on TSO for a bounded number of processes.