The FUNCTIONS statement

The FUNCTIONS statement describes the initial enablement state of optional functions provided by the XCF and XES components of z/OS®. The controllable functions are described in Table 1. The names listed in the table are the function names used in the COUPLExx FUNCTIONS statement (see z/OS MVS Initialization and Tuning Reference for the syntax) and the SETXCF FUNCTIONS command (see z/OS MVS System Commands for the syntax).

Table 1. XCF/XES Optional Functions
Name	Function	Default State
DUPLEXCF16	Enhancements to the system-managed duplexing protocol, introduced with CFLEVEL 16. When this protocol is enabled, certain duplexed commands can expedite the exchange of ready-to-complete signals between coupling facilities.	Disabled
CFLCRMGMT	Enhancements to the CFRM message-based protocol introduced with z/OS V2R1. When this function is enabled on all active systems in the sysplex, the message-based manager system may enable CFRM LOSSCONN recovery management. CFRM LOSSCONN recovery management may enhance average CF LOSSCONN recovery time by processing CF structures serially, rather than in parallel.	Disabled
SYSSTATDETECT	Enhancements to the partitioning protocol for removing a system from the sysplex. When this function is enabled, the partition monitoring system detects changes in the target system status and might be able to bypass certain delays built into the partitioning process. This support also enables the system to initiate actions, such as reset-normal, against the remote system to ensure that it is no longer actively processing.	Enabled
USERINTERVAL	When this function is enabled, the effective failure detection interval is set to the last explicitly specified INTERVAL value from one of the following sources: The INTERVAL parameter on the COUPLExx parmlib member The SETXCF COUPLE,INTERVAL command The cluster instrumentation software If the INTERVAL has not been explicitly specified, the effective failure detection interval is set to be the default value derived from the excessive spin parameters.	Disabled
CRITICALPAGING	This function controls the RSM page fault hardening behavior. When this function is enabled, the system tries not to page out to DASD the following: 31- bit common storage Address spaces that are defined as critical for paging All data spaces associated with those address spaces that are critical for paging Pageable link pack area (PLPA) If the system is experiencing a critical real frame shortage, these storage areas might be paged out by the system as a last resort. To enable the CRITICALPAGING function, use the FUNCTIONS statement in the COUPLExx parmlib member. You cannot enable the CRITICALPAGING function through the SETXCF command. However, you can use either method to disable CRITICALPAGING. For information about indicating the address spaces that are critical for paging, see SCHEDxx (PPT, master trace table, and abend codes for automatic restart) in z/OS MVS Initialization and Tuning Reference z/OS MVS Initialization and Tuning Reference.	Disabled
DUPLEXCFDIAG	When this function is enabled and the completion of a duplexed coupling facility request is delayed, software and hardware problem determination data is to be collected. The intent of this support is to collect coherent data from z/OS, coupling facilities, and message paths when it appears that a coupling facility might break duplexing for the structure that is associated with the delayed command. The function is available only when the structure is duplexed between two coupling facilities at CFLEVEL 17 or above, and when the link firmware supports the data collection function.	Disabled
COUPLINGTHININT	When this function is enabled, coupling thin interrupts in the channel subsystem which provide for improved performance and throughput for coupling facility workloads can be enabled in the channel subsystem (when available in the hardware) to deliver coupling-related adapter interrupts for coupling facility engines.	Enabled