Convert Service Unit to CPU Seconds

Fran Wong · Posted: Sat Dec 21, 2024 3:22 am

Hi,
I would like to calculate a more refined TCB and SRB CPU seconds based on SMF30 service units (i.e. SMF30CSU and SMF30SRB). In IBM documents, it said:
"(SMF30SRB*10)/SMF30SRC * SMF30SUS/16 = SRB time in microseconds",
however, SMF30SRC is always zero and therefore I cannot use this formula.

From another source, it use the formula:
"CPU Service units = CPU time * SRM Constant * CPU Coefficient".
For my case, SRM Constant is 60836.5019 which is from IBM website and CPU Coefficient is 10000 from SMF72MSRB. If my SMF30SRB is 26387, I suppose the CPU time is 0.43 seconds. However, the value in SMF30CPS is 0.37 seconds.

Can anyone please tell me how to get the CPU seconds correctly from service units?

Fran Wong · Posted: Sat Dec 21, 2024 4:35 am

Hi,

I have found the reason why I cannot work out the value using the first formula because my SMF30SRC is incorrect.

Thank you.