Some basic concepts and terminology

Sampling

The process by which Application Performance Analyzer measures activity – recording data observed during repeated, timed “snapshots”– is called “sampling.” Application Performance Analyzer saves the observed data in a “measurement file,” sometimes referred to as a “sample file.”

Non-intrusive technology

Application Performance Analyzer’s sampling mechanism is efficient, effective, and, above all, non-intrusive. Application Performance Analyzer’s measurement engine will never schedule any task to execute in the address space being measured.

The Application Performance Analyzer started task

This started task performs all of Application Performance Analyzer’s measurements. Normally, a single Application Performance Analyzer started task is active in a single MVS™ instance. In a multiple-MVS instance installation (including a sysplex), an Application Performance Analyzer started task needs to be active in each MVS instance in which measurements are to be performed.

The Application Performance Analyzer Problem Determination Tools Common Component Extension

The Application Performance Analyzer Problem Determination Tools common component extension facilitates the communication between the Application Performance Analyzer plug-in and Application Performance Analyzer for z/OS®. It is a separate UNIX process spawned by the IBM® Problem Determination Tools common component (PDTCC) running on z/OS.

The Problem Determination Tools Common Component Server

The Problem Determination Tools Common Component (PDTCC) server is an extensible server program which runs on a z/OS system to serve clients. Multiple clients can connect to a single instance of the server program and request a service by invoking a specific extension of the server. The server needs to be customized to install various extensions. Application Performance Analyzer provides an extension to connect Application Performance Analyzer plug-in users to Application Performance Analyzer on z/OS.

Multiple started tasks

In special situations you might want to run multiple Application Performance Analyzer started tasks in a single operating system instance. For example, you might want to do this when making a transition from one product version to the next. Each Application Performance Analyzer instance is identified by a unique four-character instance identifier. For simplicity, this manual discusses Application Performance Analyzer in the context of a single-instance configuration.

The Application Performance Analyzer product code and Application Performance Analyzer instance ID

The module name prefix (product code) used by Application Performance Analyzer is CAZ. We have chosen CAZ0 as the default Application Performance Analyzer instance identifier, and it is used for examples in this document.

The ISPF component

Application Performance Analyzer’s ISPF component provides the user with full, interactive access to the product’s functionality. A single, gateway dialog serves as the entry point to all interactive services. The interactive services fall into two basic categories: scheduling and managing measurement requests; and analyzing measurement data.

The Graphical User Interface

The Application Performance Analyzer graphical user interface (GUI) is an Eclipse 4.2 based plug-in that provides an alternative to the Application Performance Analyzer ISPF interface. It communicates with Application Performance Analyzer for z/OS through the Application Performance Analyzer Problem Determination Tools Common Component extension on z/OS. The Application Performance Analyzer plug-in is available as a standard feature of the Problem Determination Tools Studio product. It is also included with the Problem Determination Tools Plug-ins combined packages, dependent on the Problem Determination Tools common component plug-in.

Common data store

An optional data set unique to each Application Performance Analyzer started task (except in a sysplex environment), used to store lists of data set and directory names containing source program mapping files, and source program mapping associations. It includes one common list of data set names that can be shared amongst all users, and personal source mapping file lists for individual users. Individual users maintain their personal source mapping file lists using the ISPF A03 and A04 panels or the GUI Mapping Repository feature. Administrators maintain the common source mapping file list using the ISPF A05 panel or the GUI Mapping Repository feature.

IEFUSI exit routine

One Application Performance Analyzer module will receive control during the initiation of all job steps and started tasks, via the Step Initiation Exit (IEFUSI). During execution of this exit routine, Application Performance Analyzer determines whether a measurement has been scheduled for the job step, or started task. If it has, the exit routine will initiate sampling for the target address space. Application Performance Analyzer requires that the exit module (CAZ00990) in library hlq.SCAZLINK be added to the LNKLST.

Post-process initiation exit

One Application Performance Analyzer module will receive control during the initiation of all USS processes via the Post-process initiation exit (BPX_POSPROC_INIT). During execution of this exit routine, Application Performance Analyzer determines whether the process is a child process of one that is currently being measured by Application Performance Analyzer. If it is, the exit routine will initiate sampling for this target process. Application Performance Analyzer requires that the exit module (CAZ00991) in library hlq.SCAZLINK be added to the LNKLST.

IEFU83 exit routine

This is an optional SMF Record exit that Application Performance Analyzer will enable when measuring WebSphere® applications. The exit will receive control whenever the SMFWTM or SMFEWTM macro is invoked by WAS. The IEFU83 exit routine captures SMF type 120 subtype 9 and 10 records for active sampling requests that have the WAS data extractor turned on. All other SMF records are ignored. Application Performance Analyzer requires that the exit module (CAZ00993) in library hlq.SCAZLINK be added to the LNKLST. When this exit is enabled, you must determine the amount of above-the-bar common storage that a WAS sampling session is permitted to allocate. This value is specified in the MemObjSize in the Application Performance Analyzer-started task configuration.

IEFU84 exit routine

This is an optional SMF Record exit that Application Performance Analyzer will enable when the DB2® SMF configuration option has been enabled. The exit will receive control whenever the SMFWTM or SMFEWTM macro is invoked by DB2. It captures SMF type 101 records for active sampling requests that have the DB2+ data extractor turned on. All other SMF records are ignored. Application Performance Analyzer requires that the exit module (CAZ00994) in library hlq.SCAZLINK be added to the LNKLST. When this exit is enabled, you must determine the amount of above-the-bar common storage that a DB2+ sampling session are permitted to allocate. This value is specified in the MemObjSize in the Application Performance Analyzer-started task configuration.

J9VM sampling module

When sampling Java™ jobs, one Application Performance Analyzer module is dynamically loaded and invoked by the JVMTI agent. This module processes requests to record Java sample data in the sampling data space. Which module is loaded depends on whether Application Performance Analyzer has been configured to use a dynamically loaded JVMTI agent or a preloaded JVMTI agent, and whether the target Java application is 31-bit or 64-bit, as shown by the table below:

	31-bit	64-bit
Dynamically loaded JVMTI agent	CAZ00102	CAZ00104
Preloaded JVMTI agent	CAZ00111	CAZ00114

These modules in library hlq.SCAZLINK must be added to the LNKLST.