VMs and guest systems with batch-oriented, CPU-intensive load are preferred by VM2000 scheduling. Dialog-oriented guest systems with frequent idle times are hampered in their response times by the IO increase. If necessary fine tuning of the CPU quotas must be performed, see "Setting the CPU quotas".
The task priorities in a dialog-oriented guest system have less effect. If required, the priorities must be set anew, see the following section.
A guest system that only makes little use of its time slice is hampered in comparison with native mode by the I/O increase on the one hand and the worse cache hit rates on the other. In particular on /390 servers, execution in a CPU pool with dedicated CPUs and the VM attribute VM-ACTIVE-IDLE can help, see "VM2000 scheduling (/390 servers)".
When PCS is used the increase in a category can be influenced in both directions, see section "Using PCS (Performance Control System)".