Concurrent program metrics drawn by QUASAR numbers

Aiming at developing reliable concurrent software, the engineering practice uses appropriate metrics. Quasar, the tool that we develop for automatically analyzing the concurrent part of programs, provides some data as a result of its program analysis. We attempt to use them as metrics and to show their usefulness for software engineering and for reliable programming control. In addition to the validation of code, some delivered data may be relevant for marking the quality of code; we show that they may be useful for comparing different concurrency semantics, for comparing the execution indeterminism of different implementations of a concurrency pattern and for estimating the scalability of a solution. As a case study for providing data and insights, we present and analyze with Quasar several implementations of a distributed symmetric non-deterministic rendezvous algorithm. We consider also two possible uses of these data for indeterminacy estimation and for concurrent software quality. We conclude with a feedback on software practice.