FASTPATH processing

FASTPATH processing means that the system does not provide as much function, and thus the overall processing time is less. In particular:
  • Exit processing runs in the caller's PSW key
  • The exit routines run in the caller's state: supervisor or problem
  • The system does not provide recovery
  • The caller must provide a work area for the system to use if exit routines abnormally end
  • The system does not use a security program, such as RACF®, to do authorization-checking.

FASTPATH processing occurs when the DEFINE request enables the exit for FASTPATH processing and the CALL request specifies that exit routines are to have FASTPATH processing. Recovery for routines with FASTPATH processing is described in Recovery for the CALL request.

IBM® recommends that you do not use FASTPATH processing except when performance is a key consideration.

Parent topic: Defining an exit