Extraction of logical concurrency in distributed applications

Some methods are discussed to extract and represent the concurrency inherent in distributed applications. Concurrency is an application level property that is characterized completely by the set of messages exchanged in the application and the causal ordering relationship among the messages. The concurrency may be viewed at the logical level in the application rather than at the physical message communication level. The concurrency has a direct relationship to the message delivery performance in the underlying computation such as asynchronism in message delivery protocols. The authors quantitatively analyze how the application level concurrency influences the execution of the application. The analysis is based on methods for representing concurrency and deriving measures of concurrency from the representations. System level execution models based on ISIS, x-kernel and the causal broadcast communication system are used as case studies in the analysis. The analysis is in general useful in the design of applications and to compare their projected performance levels in an implementation-independent manner