A performance prediction framework is described in which predictive data generated by the PACE toolkit is stored and published through a Globus MDS-based performance information service. Distributing this data allows additional performance-based middleware tools to be built; this paper describes two such tools, a local-level scheduler and a system for wide-area task management. Experimental evidence shows that by integrating these performance tools for local- and wide-area management, considerable improvements can be made to task scheduling, resource utilisation and load balancing on heterogeneous distributed computing systems.