Inspect Address Space CPU Use Workspace

About the workspace

Accessing the workspace

About the default links

Modifying the default links

About the workspace

The information in the Inspect Address Space CPU Use workspace allows you to observe where in the executable code a z/OS address space is spending its time. This workspace contains three views:

This view shows the values used by the agent to collect the data. The four columns of this view show the number of samples requested, the interval at which the samples were taken in milliseconds, the number of samples collected and the number of samples used.

Normally the number of samples collected will be same as the number requested unless the job being inspected ends before the inspect agent has finished collecting data. In this  case, the number of samples collected will be the number collected up to the point where Inspect detected that the target job had ended.

The number of samples used is the number of times that the Inspect agent saw CPU activity in the target address space and gives you some indication as to the statistical accuracy of the resultant Inspect data. The more samples that actually see activity during the time the Inspect agent is running, the more accurate the overall sample will be.The number of samples used value does not represent the number of rows of Inspect data.

This view displays any error or informational messages returned by the Inspect agent. These messages help to explain the resultant data (or lack thereof) that you see in the other views. For example, if no CPU activity was seen by Inspect in the address space being inspected, the agent would return a message indicating that; the number of samples used column in the Sampling Statistics view would be zero; and no data would be displayed in the Inspect Data view.

This view contains data, drilled down to the agent-selected level of granularity within each CSECT  for the most active TCBs, sorted in descending order of CPU usage percentage. (If the agent is unable to determine CSECT information for a module, the data is returned for the load module as a whole.) The Inspect agent returns data only for elements for which it saw CPU activity.

The information in this table helps you to identify where in the code an address space is spending its time. When used in conjunction with link edit and compile or assembly listings, this information can help you to identify looping code or code that may be a candidate for a reword to improve its efficiency.

Accessing the workspace

You can link to the Inspect Address Space CPU Use workspace using one of two predefined links from the Address Space CPU Utilization table in the Address Space CPU Utilization table. When you select the link for a particular address space, the workspace is populated with Inspect data, gathered using the parameters specified in the link definition.

The workspace will not be populated by data until the Inspect agent completes on the host system. The time it takes to complete is a function of the number of samples and the sampling interval. For example, taking 1000 samples at a 5-millisecond interval (the default settings) will take 5 seconds for the data collection process to complete.

About the Inspect links

There are two Inspect links:

Using custom inspect parameters

Note: The changes you make to the Inspect link cannot be saved unless you save and rename the workspace using Save As. They will disappear when you close the Inspect workspace.

When you are selecting the values for number of samples and the sampling intervals, bear in mind that if the total time taken to execute the agent exceeds the client timeout value in the Candle Management Server, the CandleNet Portal will return no data, even if the agent subsequently completes normally.

To modify the Inspect with custom parameters link:

  1. Navigate to the Address Space CPU Utilization workspace by linking from the Address Space Counts table of the Address Space Overview workspace for the target system.

  2. Right-click the link icon beside a row in the Address Space CPU Utilization table and select Link Wizard from the pop-up menu.
    The Link Wizard editor appears.

  3. In the Selection area, select Inspect with 5000 samples at 2ms interval, then click Next >.

  4. In the Link Identity field, type a new name for the link and a description, if desired, then click Next >.
    Note that changing the name of the link will change its name in the link pop-up menu.

  5. In the Properties tree, select the INTERVAL symbol under Query - Inspect Address Space CPU Use.
    The Expression editor appears instead of the help in the right frame.

  6. In the Expression field, type the interval, in milliseconds, at which you want Inspect to collect samples.

  7. In the Properties tree, select the SAMPLES symbol under Query - Inspect Address Space CPU Use.

  8. In the Expression field, type the number of samples you want Inspect to use in deriving the data.

  9. Click Finish to save your changes and close the editor.

You should see the new name in the pop-up menu when you right-click a link icon in the Address Space CPU Utilization table.

See also:

Inspect Messages
Address Space Inspect Data Attributes

Address Space CPU Utilization Workspace

Organization of system-level predefined workspaces

Attribute groups used by system-level predefined workspaces