When working with Oracle Solaris 11, many of the executing processes compose applications, and even the operating system itself runs many other processes and threads, which takes care of the smooth working of the environment. So, administrators have a daily task of monitoring the entire system and taking some hard decisions, when necessary. Furthermore, not all processes have the same priority and urgency, and there are some situations where it is suitable to give higher priority to one process than another (for example, rendering images). Here, we introduce a key concept: scheduling classes.

Oracle Solaris 11 has a default process scheduler (svc:/system/scheduler:default) that controls the allocation of the CPU for each process according to its scheduling class. There are six important scheduling classes, as follows: