This section defines a set of conventions for writing code in which an instance of a subprogram executes on only one processor (of which there may be more than one).
If a program unit has extrinsic model SERIAL, an HPF compiler should assume that the subprogram is coded to be executed on a single processor. From the point of view of a global HPF caller, the SERIAL procedure behaves the same as an identically coded HPF procedure would. Differences might only arise in implementation-specific behavior (such as the performance).
There is currently no manner in which to specify which processor is to execute an HPF_SERIAL procedure.