Calculating the amount of service consumed

One of the basic functions of WLM/SRM is to monitor the dynamic performance characteristics of all address spaces under its control to ensure distribution of system resources as intended by the installation.

A fundamental aspect of these performance characteristics is the rate at which an address space is receiving service relative to other address spaces competing for resources within the same domain.

The amount of service consumed by an address space is computed by the following formula:

Figure 1. Formula for Calculating Service Consumption

service = (CPU x CPU service units) 
                      + (SRB x SRB service units) 
                      + (IOC x I/O service units) 
                      + (MSO x storage service units)

where CPU, IOC, MSO, and SRB are installation defined service definition coefficients and:

CPU service units =: task (TCB) execution time, multiplied by an SRM constant which is CPU model dependent. Included in the execution time is the time used by the address space while executing in cross-memory mode (that is, during either secondary addressing mode or a cross-memory call). This execution time is not counted for the address space that is the target of the cross-memory reference.
SRB service units =: service request block (SRB) execution time for both local and global SRBs, multiplied by an SRM constant which is CPU model dependent. Included in the execution time is the time used by the address space while executing in cross-memory mode (that is, during either secondary addressing mode or a cross-memory call). This execution time is not counted for the address space that is the target of the cross-memory reference.
I/O service units =: measurement of data set I/O activity and JES spool reads and writes for all data sets associated with the address space. SRM calculates I/O service using I/O block (EXCP) counts. When an address space executes in cross-memory mode (that is, during either secondary addressing mode or a cross-memory call), the EXCP counts or the DCTI will be included in the I/O service total. This I/O service is not counted for the address space that is the target of the cross-memory reference.
Storage service units =: (central page frames) x (CPU service units) x 1/50, where 1/50 is a scaling factor designed to bring the storage service component in line with the CPU component. NOT included in the storage service unit calculation are the central storage page frames used by an address space while referencing the private virtual storage of another address space through a cross service (that is, through secondary addressing or a cross-memory call). These frames are counted for the address space whose virtual storage is being referenced.