Profile data for streaming operators is collected and classified according to the function and relationship of operators, and split rules are constructed for the operators. A streams manager monitors performance of a streaming application, and when the performance needs to be improved, the streams manager determines from the split rules how to split the flow graph for the streaming application. The streams manager requests virtual machines from a cloud manager. In response, the cloud manager provisions one or more virtual machines in a cloud. The streams manager then modifies the flow graph so a portion of the flow graph is deployed to the one or more virtual machines in the cloud. In this manner a streaming application can dynamically evolve to increase its performance as needed.