MVS THRESH VARS - JOBCPUT% and JOBCPU%

Products

• SYSVIEW Performance Management

Issue/Introduction

What are the details on the VARIABLES for MVS THRESH JOBCPUT% and JOBCPU% ?

Resolution

Here some information on these 2 MVS variables

JOBCPUT% is CPU usage percentage total for all engines.
JOBCPU% is CPU usage percentage total for the LPAR.  

Note: JOBCPU% does not take into account LPAR capping, it assumes all processors are 100% available. 

The ONLY difference is that JOBCPU% takes into account the number of processors and JOBCPUT% does not.
The max value for JOBCPU% is 100, regardless of the number of processors.
The max value for JOBCPUT% = processors * 100%.

The simple way to think of it is JOBCPU% * number of CPU's = JOBCPUT%

It's possible to use the PLOT command to display the 2 variables over a time of 1 hour on the screen...
Enter PLOT JOBCPU% or PLOT JOBCPUT% and the graph is presented

For MVSTHRESH (Thresholding)..
Note: The limit value for JOBCPU% must be set based on the number of processors. This is the percentage of the total CPU in use. The variable JOBCPUT% does not divide by the number of processors.

Example: 4 processors - 100 / 4 = 25%
JOBCPU% = 25 would indicate that a job is probably using 100% of one of the processors.
If the job has multiple TCBs, then the JOBCPU% could be higher.

Processors JOBCPU%
       1            100
       2              50
       4              25
       6              16

The value of the metric will automatically adjust based on the number of online CPUs.
If a limit based on the global CPU available is required, then the JOBCPU% is the correct field.
If the threshold limit value is set to 60%, then if the job uses more then 60% of the global (all CPs) CPU, the threshold will trigger.
If dynamically 2 processors are added, then the job would have to consume more CPU to exceed 60%.
The value of the JOB CPU% metric dynamically calculates based on the number of online CPs.

If the JOBCPUT% is used an alert will be send if the number of processors changed for example

JOBCPUT% limit 240 with 4 processors alert when consumption 60%
JOBCPUT% limit 240 with 6 processors alert when consumption 40%
JOBCPU% + JOBIIP% + JOBIFA% = JOBALL%