The Scheduler schedules work in intervals. Between scheduling actions, the grid engine system keeps information about significant events such as the following:
An update of the cluster configuration
Registration of a new machine in the cluster
When scheduling occurs, the scheduler first does the following:
Takes into account all significant events
Sorts jobs and queues according to the administrator's specifications
Takes into account all the jobs' resource requirements
Reserves resources for jobs in a forward-looking schedule
Then the grid engine system does the following tasks, as needed:
Dispatches new jobs
Suspends running jobs
Increases or decreases the resources allocated to running jobs
Maintains the status quo
If share-based scheduling is used, the calculation takes into account the usage that has already occurred for that user or project.
If scheduling is not at least in part share-based, the calculation ranks all the jobs running and waiting to run. The calculation then takes the most important job until the resources in the cluster (CPU, memory, and I/O bandwidth) are used as fully as possible.