Deadlocks and dihomotopy in mutual exclusion models

Deadlocks and Dihomotopy in Mutual Exclusion Models Deadlocks and Dihomotopy in Mutual Exclusion Models

Deadlocks and Dihomotopy in Mutual Exclusion Models

Already in 1968, E.W. Dijkstra [Dij68] proposed to apply a geometric point of view in the consideration of coordination situations in concurrency. His progress graphs were the basis of the Higher Dimensional Automata (HDA) introduced by V. Pratt[Pra91] and developed in the thesis of É. Goubault[Gou95] and in later research (cf. [FGR99]). In this abstract, we stick to a simple continuous geometr...

When does a correct mutual exclusion algorithm guarantee mutual exclusion?

Dijkstra introduced mutual exclusion for an N -process system as the requirement “that at any moment only one of these N cyclic processes is in its critical section” [1]. This requirement, which we call true mutual exclusion, is still the standard definition of mutual exclusion. Mutual exclusion algorithms for shared-memorymultiprocessors do not guarantee true mutual exclusion. We give a simple...

Fast and Scalable Mutual Exclusion

We present an N -process algorithm for mutual exclusion under read/write atomicity that has O(1) time complexity in the absence of contention and (logN) time complexity under contention, where \time" is measured by counting remote memory references. This is the rst such algorithm to achieve these time complexity bounds. Our algorithm is obtained by combining a new \fast-path" mechanism with an ...

Experiments in Mutual Exclusion Bootstrapping

Mutual Exclusion Bootstrapping (MEB) was designed to overcome the problem of semantic drift suffered by iterative bootstrapping, where the meaning of extracted terms quickly drifts from the original seed terms (Curran et al., 2007). MEB works by extracting mutually exclusive classes in parallel which constrain each other. In this paper we explore the strengths and limitations of MEB by applying...