Strict priority
The scheduler never selects a lower-priority process while a higher-priority queue contains work.
What is Priority Scheduling?
A priority scheduler always selects a ready process from the highest non-empty priority queue. Processes with the same priority follow FIFO order. This simulator uses three levels: High, Medium, and Low.
Selection orderHigh → Medium → Low
Same priorityFIFO
Preemption unitConfigurable quantum
Starvation controlOptional aging
Scheduler controls
Priority Queues
High PriorityFRONT → REAR
Medium PriorityFRONT → REAR
Low PriorityFRONT → REAR
Current Process
Add a process or load the example workload.
Current time0
Ready processes0
Completed0
Promotions0
Process metrics
| Process | Priority | Burst | Remaining | Arrival | Completion | Turnaround | Waiting |
|---|
Execution log
- No scheduler events yet.
Priority scheduling concepts
FIFO tie breaking
Processes within the same priority level are served in arrival order. An unfinished process returns to the rear of its own queue.
Starvation
A steady stream of high-priority work can delay lower-priority processes indefinitely. This is called starvation.
Aging
Aging gradually promotes processes that have waited too long. Set the threshold to 0 to disable aging.
Algorithm summary
| Step | Action |
|---|---|
| 1 | Choose the front process from the highest non-empty priority queue. |
| 2 | Run it for min(quantum, remaining time). |
| 3 | Complete it or return it to the rear of its priority queue. |
| 4 | Promote waiting processes whose aging threshold has been reached. |