Overview of DFSORT performance information

Table 1 lists the main DFSORT performance areas, sources of information about each area, and suggested analysis activities for each area.

Each level of analysis discussed in Analysis techniques for DFSORT performance data produces a set of data to interpret. This figure is intended to help you associate that data with certain performance areas in DFSORT. For example, if you have decided to do a simple analysis and are concerned with your use of Blockset, you would check DFSORT messages ICE143I and ICE800I to determine whether or not the Blockset technique is being used, and if it is not, why it is not.

You can also use this figure to help you determine which level of analysis you want to do, given the performance areas you are interested in. For example, if you were concerned about intermediate merging, you would be able to tell from this figure that you would need to do moderate analysis to obtain data about this performance area.

Table 1 uses the following abbreviations:
ICExxxx
DFSORT messages (The ICE8xxI messages only appear if you have coded the SORTDIAG DD statement or if the installation option DIAGSIM=YES has been specified for your site.). See z/OS DFSORT Messages, Codes and Diagnosis Guide for explanations of the DFSORT messages.
JLOG
Job/JES log.
SMF16
SMF type-16 record (issued by DFSORT).
SMF30
SMF type-30 (subtype 4) record.
IEXIT
Information passed to the DFSORT ICEIEXIT routine.
TEXIT
Information passed to the DFSORT ICETEXIT routine (includes contents of the SMF type-16 record).

An individual source might not contain all of the information listed under Analysis.

Table 1. Sources of Performance Indicators
Area Source Analysis
Blockset ICE143I, ICE189A, ICE800I, SMF16, IEXIT, TEXIT Ensure the Blockset technique is being used or determine why it is not being used.
Intermediate merge ICE247I, SMF16, TEXIT Ensure there are no intermediate merges for a Blockset sort (if appropriate). Message ICE247I indicates an intermediate merge has taken place. An intermediate merge is a condition caused by a very low virtual storage to data set size ratio, and usually results in significant performance degradation. Providing sufficient virtual storage to DFSORT eliminates intermediate merges.
Unknown file size ICE118I, SMF16 Indicates DFSORT cannot determine the input file size. If DFSORT terminates with ICE046A or ICE083A, ensure that an appropriate value is used for FILSZ=En or DYNSPC=n.
Virtual storage ICE039A, ICE080I, ICE092I, ICE093I, ICE115A, ICE156I, ICE231I, JLOG, SMF16, SMF30, TEXIT Ensure adequate storage is available both above and below 16 MB virtual or determine how much more storage is needed.
Note: JES log messages and SMF type-30 fields can be misleading as to how much storage DFSORT actually uses. The DFSORT messages and ICETEXIT values contain the actual amount of storage used by DFSORT.
DFSORT storage options ICE128I, ICE130I, ICE131I, IEXIT, TEXIT Ensure SIZE=MAX or MAINSIZE=MAX is used and RESALL, TMAXLIM, MAXLIM, OVERRGN, DSA and MINLIM values are appropriate.
Work data sets ICE129I, ICE165I, JLOG, SMF16, SMF30, TEXIT, Determine whether dynamic allocation or JCL allocation of work data sets is used, how much work space is allocated and used, and to what types of devices the data sets are allocated. In addition, ensure that the work space is minimized.
Hipersorting ICE133I, ICE180I, IEXIT, SMF16, TEXIT Ensure Hipersorting is used, if appropriate, and determine how much Hiperspace is used.
Dataspace sorting ICE133I, ICE188I, IEXIT, SMF16, TEXIT Ensure dataspace sorting is used, if appropriate, and determine how much data space is used.
Memory object sorting ICE133I, ICE236I, ICE199I, ICE299I, IEXIT, SMF16, TEXIT Ensure memory object sorting is used, if appropriate, and determine how much memory object storage is used, and how it was used (as intermediate work storage or as an extension to main storage)
CPU time JLOG, SMF16, SMF30, TEXIT Determine the effects of tuning on CPU time.
Elapsed time JLOG, SMF16, SMF30, TEXIT Determine the effects of tuning on Elapsed time.
EXCPs ICE804I, JLOG, SMF16, SMF30, TEXIT Determine the effects of tuning on EXCPs.
Device connect time SMF30 Determine the effects of tuning on device connect time.
Storage control cache TEXIT Ensure storage control units with cache are used, and that cache fast write is used.
System determined block size ICE090I, ICE210I Ensure system-determined block size is used for output data sets, when appropriate.
Block sizes ICE088I, ICE090I, ICE2101, SMF16, TEXIT Ensure adequately large block sizes are used for input and output data sets.
Disk extents SMF16, TEXIT Ensure the number of extents required for input, output, and work data sets is minimized.
DFSORT SVC ICE145A, ICE187I, ICE191I, ICE194I, ICE816I Ensure that the DFSORT SVC is available.
Residency ICE129I Ensure that DFSORT modules are resident, if appropriate.
DFSORT level ICE000I, SMF16, TEXIT Ensure that the latest DFSORT level is installed.
Control field length SMF16, TEXIT Ensure that the control fields are only as long as necessary to distinguish the records.
EQUALS ICE128I, TEXIT, SMF16 Ensure that the EQUALS option is used only when necessary.
VERIFY ICE129I, IEXIT, TEXIT Ensure that the VERIFY option is used only when necessary.
Number of disk work data sets and devices ICE804I, JLOG, SMF16, SMF30, TEXIT For disk-only work data set applications, ensure that at least three data sets are used and that the data sets are on separate devices, if possible.
Type of application (sort, merge, or copy) ICE143I, SMF16, IEXIT, TEXIT Understand the type of application and tune accordingly.
Record length and format ICE088I, ICE089I, ICE090I, ICE091I, ICE210I, SMF16, TEXIT Understand what type of data is being processed, and tune accordingly.
Input, work, and output data set sizes ICE054I, ICE055I, ICE098I, ICE134I, ICE227I, ICE228I, SMF16, TEXIT Understand the characteristics of the data being processed, and tune accordingly.
VIO JLOG, SMF30 Ensure that VIO is only used when appropriate.