1. A method comprising: generating, by a processor of a computing device, a hierarchy of nodes organized over a plurality of levels, each node corresponding to a configuration item, the nodes corresponding to computing resources of a system, the computing resources interacting with one another to provide a business service of the system; after generating the hierarchy of nodes, generating, by the processor, a first topology corresponding to a first model, including identifying which of the nodes of the hierarchy to define the first topology as a first subset of the hierarchy of nodes, each node of the first topology having a first calculation unit for the first model, the first topology comprising the nodes of the first subset; and, after generating the hierarchy of nodes, generating, by the processor, a second topology using a same hierarchy as was used to generate the first topology, the second topology different than the first topology, corresponding to a second model different than the first model, including identify which of the nodes of the hierarchy to define the second topology as a second subset of the hierarchy of nodes different than the first subset, each node of the second topology having a second calculation unit for the second model, the second topology comprising the nodes of the second subset; outputting, by the processor, the first topology and the second topology; and determining whether the system is performing properly to provide the business service by evaluating the first model using the first topology and the second model using the second topology, including evaluating the first calculation units of the first topology and the second calculation units of the second topology within a single computational cycle, wherein generating the first topology and the second topology from the same hierarchy avoids duplication between the first topology and the first hierarchy and reduces overhead in generating the first topology and the second topology, and wherein evaluating the first calculation units and the second calculation units within the single computational cycle reduces redundancy in determining whether the system is performing properly.