Semantic service discovery architectures that operate in mobile environments must cope with the significant challenges of finding relevant services rapidly, while facing constrained computational resources. This paper presents our m-Tableaux algorithm for enabling cost-efficient and optimised semantic reasoning to support semantic service matching, on the device itself. We present a performance evaluation of the m-Tableaux optimisation strategies which clearly demonstrate its operational feasibility on a mobile device. We also present comparative evaluations with other semantic reasoners and establish the improved performance of our engine. General Terms Algorithms, Performance, Experimentation, Languages, Theory. Keywords Scalable semantic reasoning, Context-aware discovery, ServiceOriented Pervasive discovery architecture.