Measurement Session Data

The Measurement Session Data (MSD) report describes the measurement session and lets you verify whether the Performance Profile is valid. Profile validity is based on the number of samples taken, and it is quantified by the Run Time Margin of Error located under the Percent Time graph. To be valid, a Profile should have a Run Time Margin of Error of less than two percent. You can still use invalid Profiles to analyze your application, but you should treat the results as general trends rather than definite problems.

Report details

Percent Time shows graphs and statistics about execution and wait time for this Profile, gives the margin of error for the overall runtime, and lists the margin of error for the percentages shown in the Performance Profile reports that detail CPU time and wait time. Click on the chart to view details for the top CPU consumers or the top wait consumers. These are the top consumers from multiple areas such as programs, queries, transactions, etc.
Clock Time shows the length of time that the application spent in Wait or Stretch.
Processor Time show graphs and statistics about the length of time that the application spent in CPU.

The graphs will not be displayed for those profiles with fewer than 100 samples.

The MSD report is further defined by the following four tabs:

Job Environment allows you to confirm that the current Profile represents the job and program you intended to measure.
Measurement Data defines measurement parameters and measurement statistics. Measurement parameters shows values applied to the measurement request. Verify this section to ensure that Strobe applied the correct values to the measurement and attempted to collect the appropriate data. Measurement statistics provides the highest-level summary of the system resources used during the measurement session. Verify this section to determine if Strobe collected enough data for you to improve performance and to guide your further investigation. Additional measurement parameters shows more values applied to the measurement request.
Subsystems shows the name of the subsystem and parameters chosen when Strobe uses one of its options to measure a subsystem. Subsystem-specific reports appear only if this field contains the subsystem information. If you measured a subsystem application, verify this field to ensure that Strobe collected appropriate data. For systems connected to MVS coupling facilities, this field shows the coupling facility names that were in use system-wide during the measurement, to a maximum of 32 coupling facility names.
Report Data shows the parameters specific to Strobe. The parameters that display in the report are the ones used to generate the profile. Verify this section to ensure that you have produced the Strobe Performance Profile with the detail that enables you to conduct your analysis efficiently. It also shows applicable SQL Statement Analysis Messages. Clicking the icon next to the STR95965W SQL Statement Analysis Message allows you to directly view the SQL Statement text.
Time Data shows all the processor and clock times in one report. The Time Data tab will not be displayed for those profiles with fewer than 100 samples.

Analysis Tips

To determine whether you should be looking at CPU or wait reports in the Performance Profile, look at the Execution time percentage and the Wait time percentage listed under the Percent time bar graph. You should also examine the Measurement time totals to get an idea of the actual time spent using the CPU or waiting.

If the CPU time, execution time, or execution time percentage is high, examine the Program CPU Usage report to determine which active control sections are using the majority of the CPU time.
If the wait time or wait time percentage is high, examine the % Run Time Causing CPU Wait column in the Resource Demand Distribution report to determine whether file access or file-related overhead (attributed to .FILEMGT) is responsible for the wait time.