gtpm3m0i | Multi-Processor Interconnect Facility Reference |
There is no explicit common status management facility in MPIF;
however, the following should be noted:
- MPIF users identified via the IDENTIFY macro will be considered as
active.
- Paths processed by MPIF path startup will be considered as active.
- The systems connected at each end of active paths will be considered as
active.
- MPIF will police all paths for lost interrupt conditions and for
inactivity on a time basis.
- Connections will be timed-out if not completed within a predefined period
of time.
- The echo check facility will verify the availability of a path found to
have had no activity for a predefined period of time.
The MPIF echo check function exists to ensure that MPIF paths which become
inoperative do not remain undetected. Echo Check is invoked by MPIF at
a user-specified time interval. At each interval an echo check message
is sent over each started path with no activity since the last expired time
interval. If the message is not read by the other side before the next
time interval, path failure is assumed.
Potential causes of this are:
- Failure of the other system's software.
- Failure of the other system's hardware.
- Failure of a channel or CTC support in such a manner that no I/O errors
are generated.
- STOP of the other system's instruction stream.
- Unresponsiveness of the other system. This could be due to an
overloaded system, or disabling activity such as depleted core conditions, or
system error processing.