Scheduling algorithm classification

Dynamic

• make scheduling decision at run-time

• flexible to adapt

• considers only actual task requests and execution time parameters

• large run-time overhead finding a schedule

Static

• make schedule decisions at off-line(also called pre-run-time)

• generates a dispatching table for run-time dispatcher at compile time

• needs complete knowledge of task before compiling

• small run-time overhead

Preemptive

• currently executing tasks may be interrupted(preempted) by higher priority processes

• the preempted process continues later at the same state

• potential frequent contexts switching

• useless for disk and network cards

Non-preemptive

• running tasks will be allowed to finish its time-slot(higher priority processes must wait)

• reasonable for short tasks like sending a packet (used by disk and network cards)

• less frequent switches

References

• http://slideplayer.com/slide/8772194/