1. Method of performance monitoring in a data processing environment, wherein the data processing environment comprises multiple systems, each of which comprises resources, wherein each resource relates to a resource type, wherein at least one performance parameter is defined for each resource type, the method comprising: determining a value of the at least one performance parameter for at least one resource, aggregating performance parameter values and related resources of a resource type, creating for at least a part of the resources a next predefined aggregation level which includes all resources relating to the resource type and associating all performance parameter values to this aggregation level, and repeating the creating for at least a part of the resources a next predefined aggregation level until a predefined target aggregation level of the data processing environment has been reached.