Determining the amount of above-the-bar common storage for the IEFU83 and IEFU84 exits
The optional Application Performance Analyzer IEFU83 and IEFU84 exit routines are used to record SMF data for WebSphere® (WAS) activity, and DB2® accounting data which is captured for all DB2+ requests, respectively. They require above-the-bar common storage for each sampling request that captures these SMF records. You must specify the total amount of storage in the Application Performance Analyzer started task CONFIG SAMPLE keyword MemObjSize. This section provides guidelines to determine the amount of above-the-bar common storage required by Application Performance Analyzer.
Calculating the Storage for WebSphere (WAS) Requests
The following table shows the SMF record type 120 subtype 9 sections that are recorded by Application Performance Analyzer for each request processed by WAS.
| Name | Description | Length | Minimum Repetitions | Maximum Repetitions | Maximum Total Length |
|---|---|---|---|---|---|
| APA | Memory Object Header | 8 | 1 | 1 | 8 |
| SM120ST9 | Header | 204 | 1 | 1 | 204 |
| SM120S91 | Platform Neutral Server Info Section | 76 | 1 | 1 | 76 |
| SM120S92 | z/OS® Server Info Section | 68 | 1 | 1 | 68 |
| SM120S93 | Platform Neutral Request Info Section | 68 | 1 | 1 | 68 |
| SM120S94 | z/OS Request Info Section | 428 | 1 | 1 | 428 |
| SM120S96 | Network Data Section | 188 | 0 | 1 | 188 |
| SM120S97 | Classification Data Section | 144 | 0 | 5 | 720 |
| SM120S99 | CPU Usage breakdown section | 548 | 0 | 30 | 16440 |
| SM120S9B | Async Work Data Section | 588 | 0 | 1 | 588 |
| Total | 852 | 18200 |
| Name | Description | Length | Minimum Repetitions | Maximum Repetitions | Maximum Total Length |
|---|---|---|---|---|---|
| APA | Memory Object Header | 8 | 1 | 1 | 8 |
| SM120STA | Header | 204 | 1 | 1 | 204 |
| SM120SA1 | Platform Neutral Server Info Section | 76 | 1 | 1 | 76 |
| SM120SA2 | z/OS Server Info Section | 156 | 1 | 1 | 156 |
| SM120SA3 | Outbound Request Info Section | 160 | 1 | 1 | 160 |
| SM120SA4 | WOLA Outbound Request Type Specific Section | 552 | 0 | 1 | 552 |
| SM120SA5 | Outbound Request Transaction Context | 168 | 0 | 1 | 168 |
| SM120SA6 | Outbound Request Security Context | 40 | 0 | 1 | 40 |
| SM120SA7 | Outbound Request CICS context | 112 | 0 | 1 | 112 |
| SM120SA8 | OTMA Outbound Request Type Specific Section | 328 | 0 | 1 | 328 |
| Total | 604 | 1476 |
The minimum size for a WAS request is 604 bytes. The maximum size for a WAS request is 18200 bytes. The actual size required for a WAS request is dependent on the type of request. For example, the Network Data Section is not used for Message Driven Bean (MDB) requests.
To calculate the amount of APA memory object storage required, multiply the average request size by the number of WAS requests that will be processed during a WAS sampling session.
- For example, if the average WAS request has a Network Data Section, 3 Classification Data Sections and 3 CPU Usage Breakdown Sections, then the size of each request is 852 + 188 + (3 x 144) + (3 x 548) = 3116 bytes.
It will be up to each installation to determine the average request size based on their WAS processing profile and the number of WAS requests that would be created during a typical sampling session. Multiply the size of the average WAS request by the number of WAS requests per typical sampling session to determine the WAS component of memory object size (MemObjSize).
Calculating the Storage for DB2+ Requests
During a sampling session, each DB2 thread will require 208 bytes of memory object storage. Multiply the anticipated number of threads during a sampling session by 208 bytes to determine the DB2 component of the memory object. The number of threads will depend on the DB2 attach type that’s being used in the sampled address space. Typically, TSO, CAF, and RRSAF attachments will have one thread. The number of threads for IMS™ and CICS® attach types will depend on thread reuse. For the IMS attach type, the number of threads will correspond to the number of transactions processed in the sampled region. The number of threads for the CICS attach will depend on the ACCOUNTREC parameter on the CICS DB2CONN definition.