Mainframe, MVS and zOS Discussion

Hi,

Can we convert CPU hours into MIPS? I searched this over the net and found this defintion:

One MSU = 6 Mips (here MSU and Mips represent a consumption speed, not an accumulated consumption). So a job that constantly uses 10 MSU (as displayed by monitors) uses 60 Mips.

To convert CPU seconds (accumulated consumption) to Mips (average consumption speed): Mips = (CPU seconds)*EUM/(Elapsed seconds) where EUM=EQUIVALENT UNIPROCESSOR MIPS as defined in the REXX exec below. Example: a job has used 100 CPU seconds during 1 minute (it is a multi-task job). The system is a 2064-1C5 (1085 MIPS, EUM=217 MIPS). The average consumption speed of this job is 100*217/60=362 MIPS.

This is very confusing because my understanding was that every IBM machine will have its own MIPS/MSU ratings and we should generalize One MSU= 6 MIPS ...

every IBM machine will have its own MIPS/MSU

which is the EUM in the quote you posted. MIPS is Million Instructions Per Second and hence you would take the CPU seconds divided by the elapsed seconds to determine the "Per Second" piece and then multiply by the appropriate multiplier for the processor to come up with the MIPS value.

The conversion of MIPS to MSU (or vice versa) varies by the processor family (z900, z10, z12, z13) and even within the processor family. Furthermore, the MIPS / MSU ratio varies by release of z/OS even for a processor family, and there is not just one MIPS / MSU ratio since the ratio varies depending upon the processor workload. If you want to find out more, start with the IBM Large System Performance Reference (LSPR) and proceed from there -- Google is your friend.