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ISGCNFXITSYSTEM — Filter Global Resource Serialization Contention Notification, SYSTEM Scope z/OS MVS Installation Exits SA23-1381-00 |
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ISGCNFXITSYSTEM provides a way for your installation to suppress the ENF 51 signal that global resource serialization issues to notify programs of contention for a scope=SYSTEM resource. When at least one exit routine has been added to the ISGCNFXITSYSTEM exit, it will receive control for every resource of system scope that Global Resource Serialization finds in contention. Depending on what your installation specified in the exit routine, the exit can suppress the ENF 51 signal for the resource in contention. This allows the installation to suppress ENF signals for resources known to be frequently in contention, with the trade-off of providing less data to any monitoring tools that listen for those signals. Replacing the Exit RoutineFor information regarding dynamic exit routine replacement, see Replacing a Dynamic Exit Routine. Exit Routine EnvironmentISGCNFXITSYSTEM
receives control in the following environment:
Exit Recovery is as follows.
Exit Routine ProcessingThe ISGCNFXITSYSTEM exit point allows an exit routine to suppress the ENF 51 signal when global resource serialization detects contention on a system scope resource. The exit routine is passed a parameter list, CNFP (mapped by CNFP), which contains information about the request. The exit routine can check the QNAME, RNAME, and Rnamelen of the resource and filter the ENF 51 signal. Programming ConsiderationsObserve
the following considerations when coding an exit routine to filter
global resource seriaqlization contention notification on a system
scope:
Entry SpecificationsThe system passes a parameter list (CNFP) to the exit routine. Registers at Entry: The contents of the registers on entry to the exit are as follows.
Parameter List Contents: Register 1 contains the address of the exit parameter (CNFP) that is mapped by macro ISGYCNFP. The parameter list contains the QNAME, RNAME, and Rnamelen of the resource, the filter flag, and a 4K work area. You should not use this work area to communicate among multiple exit routines because the work area may not be cleared upon entry. In addition, in certain recovery scenarios the work area may not be the same for all routines. Return SpecificationsAt the completion of ISGCNFXITSYSTEM processing, ISGYCNFP can indicate that the ENF 51 signal be suppressed by setting the CNFP_FILTER flag. Registers at Exit: Upon return from the exit processing, the register contents must be as follows.
Coded Example of the Exit RoutineIBM® provides coded examples of the ISGCNFXITSYSTEM and ISGCNFXITSYSPLEX exit routines in member ISGCNFXR of SYS1.SAMPLIB. |
Copyright IBM Corporation 1990, 2014
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