Managing user expectations with component performance contracts

In this paper we introduce a definition of performance contract for hierarchical component applications communicating through one-way asynchronous communications. Component annotations allow to express a generic performance model, performance requirements and resource constraints. We propose an $O(n. 3.5})$ algorithm to obtain from user expectations the minimum resource requirements which ensure the desired QoS, to be exploited successively in a SLA negotiation phase. The technique is suitable for automatic execution, exploiting developer-provided annotations, and is validated with experiments on heterogeneous grid platforms.