In these years, grid computing is probably the most promising approach
for building large scale and cost effective applications. However, this
very popular approach needs a sophisticated software infrastructure to address
several requirements. One of these requirements is the ability to sustain a predictable
performance in front to the fluctuations related to the dynamic nature
of a grid. In this paper we describe design and realization of a Performance
Contract System, a software infrastructure that manages the computational kernel
of a grid application with the aim to face such aspect of the grid computing,
as well as the strategies and the experiences to integrate it in a gridenabling
component-based programming environment still under development.