Methods, systems, and products are disclosed for executing an application on a parallel computer having a plurality of nodes. Executing an application on a parallel computer includes: booting up a first subset of a plurality of nodes in a serial processing mode; booting up a second subset of the plurality of nodes in a parallel processing mode; profiling, prior to application execution, an application to identify serial segments of the application, parallel segments of the application, and application data utilized by each of the serial segments and the parallel segments; and executing the application on the plurality of nodes, including migrating, in dependence upon the profile for the application upon encountering the parallel segments during execution, only specific portions of the application and the application data from the nodes booted up in the serial processing mode to the nodes booted up in the parallel processing mode.