1. A method for selecting an operator graph configuration for a stream-based computing application, comprising: performing a first simulated processing of the stream-based computing application using a first simulation condition, the first simulation condition specifying a first operator graph configuration; performing a second simulated processing of the stream-based computing application using a second simulation condition, the second simulation condition specifying a second operator graph configuration, the second simulation condition being distinct from the first simulation condition; each simulated processing including inputting a stream of test tuples to the stream-based computing application, the stream-based computing application operating on one or more compute nodes, each compute node having one or more computer processors and a memory to store one or more processing elements, each processing element having one or more stream operators; monitoring each simulated processing to determine one or more performance metrics; sorting the first and second simulated processings based on a first performance metric to identify a simulated processing having a first rank; and selecting an operator graph configuration associated with the simulated processing having the first rank if the first performance metric for the simulated processing having the first rank is within a processing constraint.