Faster Asynchronous Systems

A testing scenario in the sense of De Nicola and Hennessy is developed to measure the worst-case efficiency of asynchronous systems. The resulting testing-preorder is characterized with a variant of refusal traces and shown to satisfy some properties that make it attractive as a faster-than relation. Finally, one implementation of a bounded buffer is shown to be strictly faster than two others – in contrast to a result obtained with a different approach by Arun-Kumar and Hennessy.