Using ICETEXIT data

DFSORT enables you to provide an installation termination exit (ICETEXIT) routine which can be used to collect extensive performance-related information about all DFSORT applications at a site.

If present and activated, the ICETEXIT routine is called at the end of DFSORT application processing. It is available for those who wish to make a thorough analysis of DFSORT performance data using a single source of information. See z/OS DFSORT Installation and Customization for complete information on how to write and install an ICETEXIT routine.

ICETEXIT provides comprehensive information on each DFSORT application, including the information contained in DFSORT's type-16 SMF record.

Note: The SMF record is available to the ICETEXIT routine even if the SMF facility is not being used (in this case, the SMF record is constructed and passed to the ICETEXIT routine, but not written to the SMF data set).

Additional information available to the ICETEXIT routine includes:

Control statements specified
User exits used
Options (for example, VERIFY) in effect
Control field formats used
Work data set EXCPs broken down by data set and DFSORT phase
Use of cache fast write
Virtual storage statistics
DFSORT phase timing statistics (elapsed, TCB, SRB)
Input and output data set statistics
Hipersorting statistics
Sorting with data space statistics
Memory object sorting statistics

In some cases, you only need a portion of this information for performance and tuning reasons.

The advantage of using an ICETEXIT routine is that all the information about each DFSORT application is available to the routine. You do not need to use information from a number of other sources. How you process the data depends on your requirements.

Examples of how you can use an ICETEXIT routine include:

Collating information from SMF type-16 records with run-time and installation option values to identify applications with options which degrade performance.
Write an SMF record using your own format.

You can write the record to a private data set for subsequent processing.

You can process SMF records or private data set records using an appropriate data reduction program.

The example in Sample ICETEXIT provides a sample ICETEXIT assembler routine. This installation-wide exit creates a user SMF record from the data passed by DFSORT.

The assembler source for an SVC which writes the user SMF record to SMF is also included. This enables the ICETEXIT routine to run unauthorized but write SMF records using the SVC.

See z/OS DFSORT Installation and Customization for more information on how to write and install an ICETEXIT routine,