First, for ease in understanding the suggested standard values for resource workloads, it is helpful to quantify the work of BS2000.
System time (SIH time) is required primarily for handling the following events:
controlling multiprogramming operation
carrying out DMS I/O operations
carrying out paging.
The following standard values apply to a CPU working at full capacity:
The SIH portion should not be more than 20% (/390 servers) or 10% (x86 servers), even in the case of heavy DMS I/O activity.
With normal loads, the time taken up for controlling multiprogramming operation amounts to 5 - 10% (/390 servers) or 3 - 5% (x86 servers) of the full capacity of the CPU involved.
With the usual workload and a balanced configuration, the following SIH portions apply for
executing DMS I/O operations: 3 - 6% (/390 servers) or 2 - 4% (x86 servers)
executing paging: max. 2% (/390 servers) or max. 1% (x86 servers)
When interpreting the values measured with SM2, the user is advised to proceed in the order of the sections which follow.