Fast Communication Mechanisms--Coupling Hardware Distributed Shared Memory and User-Level Messaging
Hermann Hellwagner, Wolfgang Karl, Markus Leberecht · 1997
Low latencies for small messages are an important factor of efficient fine-grained parallel computation. The Active Messages concept provides this minimal overhead by eliminating certain parts of the critical path of sending and receiving messages, that is the context switch into the operating system kernel when using user-mode I/O, and multiple buffering in the network layer. Hardware-supported distributed shared memory (DSM) architectures exhibit various properties that make them particularly useful for an implementation of the aforementioned messaging mechanisms. This paper thus describes the concept, implementation, and the performance of a DSM-based Active Messages layer. Keywords: Distributed Shared Memory, Active Messages, User-Level Communication, Scalable Coherent Interface 1 Introduction and Motivation Networks of workstations (NOWs) have become increasingly popular as widely available facilities for parallel processing. This has been fostered by the availability of public...