Scalable service composition execution by means of an asynchronous paradigm

In this paper we describe our findings and experiences with regards to scalable service composition execution. More specifically we detail the process of redesigning our original core for service composition execution to adhere to a more asynchronous, event-driven, non-blocking paradigm. The outcome of this work is an asynchronous core that is scalable; limited by the amount of available memory and not by the number of available processing threads. Another characteristic of the asynchronous core is robustness as system starvation is not possible. Our findings are evaluated with performance results comparing the new asynchronous core to its predecessor. The evaluation focuses on two aspects; throughput and overhead. Our results show that the overhead introduced by service composition is very small: 4 to 12 msec. In addition, the new asynchronous core provides better throughput ranging from +3% to +49% for moderate load and no upper limit for higher load.