INTER-ENTRY SELECTION CONTROL MECHANISMS - IMPLEMENTATION AND EVALUATION

Inter-process communication is achieved in many concurrent programming languages through message entries. Many of these languages contain in ter-entry selection constructs allowing a process to selectively choos e one of a group of message entries to service. Generally, this select ion process is handled non-deterministically. To enable a degree of co ntrol over this selection, limited inter-entry selection control mecha nisms are available in several of these languages. This paper reviews the need for more expressive inter-entry selection control mechanisms and details the design and implementation of two such control mechanis ms-static and dynamic preferences. These implementations of static and dynamic preferences, SRps and SRpd respectively, are extensions of th e SR concurrent programming language. In both implementations, the use of preferences is optional, and thus, the overhead associated with th eir use is incurred only when their use is necessary. Finally, this pa per describes the performance of these implementations on several clas sical synchronization problems. For tests run in a shared memory envir onment the results show that there is substantial cost associated with the preference implementations. However, the results of the distribut ed environment tests illustrate that the incremental cost of adding pr eferences is small and often not discernable when the overhead costs a ssociated with communications across a network are considered. Copyrig ht (C) 1997 Elsevier Science Ltd.