The SMFSJT query generates several chart sets. The chart sets show the daily top nn (default 10) started tasks, by job name, using CPU, I/O, and central storage (memory) resources on your z/OS systems. For each resource type, one chart set shows the top ten started tasks using the resource over the entire Central Processing Complex (CPC), and another that shows the top ten started tasks for each z/OS system. The query reads detail data from the BAT_ST (System Task Program Activity) file, and summarizes the data by job name. The charted data reflects summarized interval and step record information from all job steps for the top ten started tasks.
Note: While the chart samples displayed in this guide present the Top nn started tasks alphabetically, from left to right on the x-AXIS, the query has been updated to present the Top nn started tasks in order of descending resource use. The name of each started task is prefixed with the resource usage rank. (for example, 01- jobnamea, 02-jobnameb, and so on.
For CPU, the CPU time used by each of the top ten started tasks is displayed using a vertical bar. The bar is segmented by CPU time type (for example, TCB, SRB, I/O Interrupt, zIIP, zAAP, and so on). Two horizontal lines show the program count (number of unique program executions) and interval count (number of interval records) encountered for the started task. For short running steps, the interval count and program count values have similar values. For long running programs, the interval count exceeds the program count.
Note: The program count data element (PGMCOUNT) is only set to one (1) for the last interval record for a long running program. For started tasks with a long running program step that has not yet ended, PGMCOUNT is zero.
For I/O, I/O Service Units are used to determine the top ten started tasks. Three different chart views are available to display I/O related resource utilization. The first view shows I/O service units for the top ten using vertical bars. The second view displays device connect time for the top 10 by device class (for example, DASD, TAPE, Unit Record, and so on). The device connect time is displayed using a vertical bar, with the bar segmented by the time connected to each of the device classes. The final view shows EXCPs by device class, again using a segmented vertical bar. As with the CPU chart, the program and interval record count are shown using a horizontal line.
For central storage, the top ten started tasks with the largest average working set size are displayed. Average working set size is the average number page frames in central storage used by the program. The page frame count is shown using a vertical bar and the program and interval record count are shown using a horizontal line.
Note: The average working set size represents the average for all step and interval records encountered for each top ten started task.
The example shows the CPC level chart generated for started tasks executing on an IBM z196 2817-615 CPC. The largest user of CPU time was the started task ‘APLA1JBO’. The chart shows that for the day depicted, the started task only had 8 step completions spanning 101 interval records, and consumed just over 11 hours of CPU time. Most of this time was Normalized zIIP CPU time. The normalization of zIIP CPU time is important for this CPC model because the CP engines run slower than the specialty (zIIP/zAAP) engines. When zIIP or zAAP CPU time is normalized, the value is expressed as the CP engine equivalent by multiplying by a normalization factor. For the 2817-615 CPC model, the normalization factor is 1.52734.
|
Copyright © 2014 CA.
All rights reserved.
|
|