CPU Shares and Process State

In the Solaris operating environment, a project workload usually consists of more than one process. From the fair share scheduler perspective, each project workload can be in either an idle state or an active state. A project is considered idle if none of its processes are using any CPU resources. This usually means that such processes are either sleeping (waiting for I/O completion) or stopped. A project is considered active if at least one of its processes is using CPU resources. The sum of shares of all active projects is used in calculating the portion of CPU resources to be assigned to projects.

The following formula shows how the FSS scheduler calculates per-project allocation of CPU resources.

Figure 9-1 FSS Scheduler Share Calculation

When more projects become active, each project's CPU allocation is reduced, but the proportion between the allocations of different projects does not change.