FORMULA FOR TCB-CPU-TOT FIELD

Document ID : KB000015301
Last Modified Date : 14/02/2018
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Question:

How is the TCB-CPU-TOT IQL field derived out of SMF fields? We would like to know the specific formula. The reason for the question is that we have migrated from IBM Omegamon PE SMF metrics to using VYSVIEW for DB2 SMF offloaded data and we see discrepancies in class1 CP CPU data. specifically, the class1 CPU reported via SYSVIEW is always higher than the Omegamon one. Class1 elapsed time and class2 elapsed and CPU time practically show no discrepancies. Ideally, we would like CA to help us understand the reason for the above discrepancies.

Answer:

For non-rollup threads TCB-CPU-TOT=(QWACEJST-QWACBJST) +QWACSPCP+QWACUDCP

 For rollup threads TCB-CPU-TOT=QWACEJST +QWACSPCP+QWACUDCP

According to IBM Knowledge Center for Tivoli OMEGAMON XE for DB2 Performance Expert on z/OS

CLASS 1: MVS TCB TIME

The amount of MVS CPU time used. If the time cannot be calculated or the value is negative, N/C is printed in this field. Calculated from the DB2 field QWACEJST - QWACBJST.