Constructive and Adaptable Distributed Shared Memory

Distributed shared memory (DSM) is a paradigm for programming distributed systems, which provides an alter-native to the message passing model. DSM offers the agents of the system a shared address space through which they can communicate with each other. The main problem of a DSM implementation on top of a message passing sys-tem is performance. Performance of an implementacion is closely related to the consistency the DSM system offers: strong consistency (all agents agree about how memory events happen) is more expensive to implement than weak consistency (disagreements are allowed). There have been many DSM systems proposals, each one supporting differ-ent consistency levels. Experience has shown that no one is well suited for the whole range of problems. In some cases, strong consistent primitives are not needed, while in other cases, the weak semantics provided are useless. This is also true for different implementations of the same mem-ory model, since performance is also afected by the data access patterns of the aplications. In this paper, we introduce a novel DSM model called Mume. Mume is a low level layer close to the level of the message passing interface. The Mume interface pro-vides only the minimum requirements to be considered as a shared memory system. The interface includes three types of synchronization primitives, namely, total ordering, causal ordering and mutual exclusion. This allows efficient imple-mentations of different memory access semantics, accomo-dating particular data access patterns