Analysis of workflow protocol adaptability in TestLAN production systems

The testing local area network, TestLAN, is an approach to the design of integrated testing systems. Its objective is to link a network of testers such that distributed clients (jobs) requiring testing services can be served efficiently with minimum delays through the use of dynamic priority assignment, time-out, and resource allocation protocols. Previous research has shown this approach to improve performance, but assumed that the protocols are static. Events such as demand fluctuation and design changes, however, can affect the usefulness of the protocol logic, thereby adversely affecting the performance of the system. This paper investigates the thresholds of change and the time at which protocols should be re-evaluated for possible changes. The results of the analysis show that significant improvement can be gained by protocol adaptation, with certain cases realizing improvement in the flow time by as much as 32%, compared to the non-adaptable TestLAN. However, differences among adaptation methods are more difficult to generalize, as they depend on the particular cases. In many cases, adapting protocol logic when thresholds are in the range 0.2 <=(delta)<= 0.4, the percentage change of the parameters of the system in either direction, reduces flow time significantly, yet these thresholds are not general. The importance of this analysis is that the experiments cover a large space of general conditions, and general design recommendations for protocol adaptation are developed.