Int. J. Innovative Computing and Applications, Vol. 2, No. 3, 2010 143 Copyright © 2010 Inderscience Enterprises Ltd. A GRASP for a resource-constrained scheduling problem Renaud Sirdey 1 * CEA LIST, Embedded Real Time Systems Lab, Point Courrier 94, 91191 Gif-sur-Yvette Cedex, France E-mail: renaud.sirdey@cea.fr *Corresponding author Jacques Carlier and Dritan Nace UMR CNRS Heudiasyc, Université de Technologie de Compiègne, Centre de Recherches de Royallieu, BP 20529, 60205 Compiègne Cedex, France E-mail: jacques.carlier@hds.utc.fr E-mail: dritan.nace@hds.utc.fr Abstract: This paper is devoted to the approximate resolution of a strongly NP-hard real world resource-constrained scheduling problem, which arises in relation to the operability of certain high availability real time distributed systems. We present a fast and pragmatic algorithm based on the GRASP metaheuristic and, building on previous research on exact resolution methods, extensive computational results demonstrating its practical ability to find solutions within a few percents to optimality on a wide spectrum of hard instances. Keywords: combinatorial optimisation; scheduling; GRASP; distributed systems; OR in telecommunications. Reference to this paper should be made as follows: Sirdey, R., Carlier, J. and Nace, D. (2010) ‘A GRASP for a resource-constrained scheduling problem’, Int. J. Innovative Computing and Applications, Vol. 2, No. 3, pp.143–149. Biographical notes: Renaud Sirdey is a Researcher at Commissariat à l’Energie Atomique, the French atomic energy research agency. His main research interests include parallelism, compilation, graph theory and combinatorial optimisation. Prior to that, he held various R&D positions in the telecommunications industry. He received a diplôme d’ingénieur and a PhD in CS from Universitè de Technologie de Compiègne (UTC) as well as an MSc in Applied Maths from Cranfield University (UK). He teaches software engineering at Ecole Nationale Supérieure de Techniques Avancées (Paris) as well as operations research at UTC. Jacques Carlier is Professor of CS as well as the Head of Doctoral Studies in CS at the Université de Technologie de Compiègne. His main research interests include scheduling, combinatorial optimisation, graph theory and bin-packing. He received his PhD in CS as well as a Doctorat d’Etat both from Paris VI University and is an alumnus of Ecole Normale Supérieure de Cachan. Dritan Nace is Professor of CS at the Université de Technologie de Compiégne. His main research interests include networks optimisation, robustness, linear programming and combinatorial optimisation. He received his PhD in CS as well as his Habilitation à Diriger les Recherches both from the Université de Technologie de Compiègne. 1 Introduction In this paper, we present a GRASP for the process move programming (PMP) problem. This problem arises in relation to the operability of certain high-availability distributed switching systems. For example, Sirdey et al. (2003), consider a telecom switch managing radio cells on a set of call processing modules, hereafter referred to as processors, of finite capacity in terms of erlangs, CPU, memory, ports, etc.; each radio cell being managed by a dedicated process running on some processor. During network operation, some cells may be dynamically added, modified (transreceivers may be added or removed) or removed, potentially leading to unsatisfactory resource utilisation in the system. This issue is addressed by first obtaining a better system configuration and by subsequently reconfiguring the system, without violation of the capacity constraints on the processors.