Software, Performance and Resource Utilisation Metrics for Context-Aware Mobile Applications

Abstract

Abstract

Runtime metrics collection for middleware supported adaptation of mobile applications

“…The metrics of Ryan and Rossi [9] have been chosen as the basis for this solution, since they are specifically intended for mobile application adaptation as well as having been derived from a series of mathematical models and empirically validated. Furthermore, the metrics were empirically shown to improve the application performance in a real adaptation scenario following a change in the execution environment.…”

“…It would however be beyond the scope of this paper to implement and test the full suite of metrics listed in [9], and thus in order to provide a useful non-random subset, we chose to implement the minimum set of metrics necessary to implement local and global adaptation [9] and thereby satisfy a range of real adaptation scenarios. As such the solution presented in this section is discussed primarily in terms of these metrics, although the structure of the solution is intended to support the implementation of the remaining metrics, as well as other unspecified metrics such as those related to quality and resource utilisation.…”

“…Following are brief examples of a number of these metrics in order to demonstrate their usage in an adaptation scenario. As Processor Usage (PU) on a certain host increases, the Execution Time (ET) of a given method executed on that host also increases [9], thus facilitating the decision of whether to move an object with high ET to another host with low PU. Invocation Time (IT) shows the overhead of invoking a certain method, with the invocation overhead of marshalling parameters and transmitting remote data for a remote call being orders of magnitude higher than the cost of pushing and popping data from the method call stack.…”

“…In order to collect IT metrics, another additional metric is needed. Ryan and Rossi [9] define the metric Response Time (RT), as the total time taken for a method call to finish, which is the sum of IT and ET. The Response Time can be measured directly using the same timer based technique used to measure ET, although at the start and end of the proxy call rather than the method implementation.…”

“…For example, service-based adaptation, in which service quality or service behaviour is modified in response to changes in the runtime environment, generally requires detailed environmental metrics but only simple software metrics [4]. On the other hand, adaptation via object mobility [6], also requires detailed software metrics [9] since object placement is dependent on the execution characteristics of the mobile objects themselves.…”