1. FCFS algorithm (first come first serve):
Each schedule selects one or more jobs from the queue that enter the queue first.
Not good for short jobs
Good for long jobs
2. SJ(P)F algorithm (short job/process priority scheduling algorithm)
Each schedule selects one or more shortest-running jobs from the queue.
Not good for long jobs
May cause long jobs not to be called for a long time
Good for short jobs
Minimum average wait time and minimum average turnaround time.
3. Priority scheduling algorithm
1) Non-deprivation
When a process is running, a process L with a higher priority comes in, and the system runs the current process before running L.
2) Deprivation
When a process is running, a process L with a higher priority comes in, and the system stops the current process and runs L.
4. High response ratio priority scheduling algorithm
The process with the highest response ratio is scheduled.
Response ratio = (waiting time + requested service time) / requested service time
Customer service is hungry and takes into account long jobs. It is a balance of FCFS and SJF.
5. Time Rotation Scheduling Algorithm
Applies to time-sharing systems.
If the time slice is too large, and the processes all run in one time slice, it degenerates into the FCFS scheduling algorithm.
If the time slice is too small, the scheduling frequently switches processes, and the overhead is high.