Executing a service program for an accelerator application program in a hybrid computing environment that includes a host computer and an accelerator, the host computer and the accelerator adapted to one another for data communications by a system level message passing module; where the service program includes a host portion and an accelerator portion and executing a service program for an accelerator includes receiving, from the host portion, operating information for the accelerator portion; starting the accelerator portion on the accelerator; providing, to the accelerator portion, operating information for the accelerator application program; establishing direct data communications between the host portion and the accelerator portion; and, responsive to an instruction communicated directly from the host portion, executing the accelerator application program.