Changing your coefficient values

Prior to z/OS® V1R3, you could use the same coefficients as used in the IEAIPSxx parmlib member. Then you could directly compare RMF™ data, and determine your durations properly.

However, if you plan to use workload management, it is probably a good time for you to rethink your coefficients. The current defaults are inflated, given the size and processing capability of processors. Processors can consume much higher amounts of service, and as a result, service unit consumption numbers are very high. These high numbers can cause problems if they reach the point where they wrap in the SMF fields. If they wrap, you may see abnormally large transaction counts, and last period work may be restarted in the first period.

It is possible for you to make them smaller, yet still maintain the same relationship between the coefficient values. Consider changing your definitions to the following:

CPU: 1
IOC: 0.5
MSO: 0
SRB: 1

If you do decide to change the coefficients, you must re-calculate your durations and accounting procedures.

Tip: If you want to gather storage service information by service class, but don't want it affecting your durations or accounting procedures, use an MSO coefficient of 0.0001. This results in very low MSO service unit numbers, but still allows you to obtain storage service information through RMF.

Since changing the coefficients affects durations and accounting values, the defaults are meant to be consistent with settings seen in the field today. If you do not define the service coefficients, the defaults are:

CPU: 10.0
IOC: 5.0
MSO: 0.0
SRB: 10.0