Shortest-Job-First (SJR) Scheduling
- Associate with each
process the length of its next CPU burst.
Use these lengths to schedule the process with the shortest time.
- Two schemes:
- nonpreemptive – once CPU given to the
process it cannot be preempted until completes its CPU burst.
- preemptive – if a new process arrives with
CPU burst length less than remaining time of current executing process,
preempt. This scheme is know as the
- Shortest-Remaining-Time-First (SRTF).
- SJF is optimal – gives
minimum average waiting time for a given set of processes.
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