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See how the CPU decides who runs next

An interactive playground for CPU scheduling. Enter your own processes, pick a policy, and step through the simulation tick by tick — with the Gantt table, ready queue and turnaround metrics updating live.

No account needed · Works offline · Light & dark theme

Everything you need

From arrival to completion, visually

Simulate

Watch every tick of the CPU

Press run and follow the clock second by second: who holds the CPU, who is waiting, who just finished — with narration for every arrival, preemption and completion.

Run / pause / step0.5× – 2× speedLive ready queueEvent narration
Understand

Read results like a table

The Gantt table fills one cell per time unit, the ready queue updates underneath, and finish time, turnaround (Tr), Tr/Ts and waiting are computed for every process.

Gantt tableQueue levelsTurnaround TrTr / Ts ratio
Compare

Put all six policies head to head

Run every algorithm on the same workload and see which one wins on average turnaround, normalized Tr/Ts and waiting time — with the best value highlighted.

Side-by-side averagesTurnaround barsPer-policy details
The algorithms

Six classic policies, one workload

First-Come, First-Servednon-preemptivemax w
Round Robinpreemptivecyclic (FIFO)
Shortest Process Nextnon-preemptivemin s
Shortest Remaining Timepreemptivemin s' (remaining)
Highest Response Ratio Nextnon-preemptivemax (w + s)/s
Feedback Schedulingpreemptivemin level (FIFO)
How it works

Three steps to scheduling intuition

  1. Enter processes. A five-process example is preloaded — edit, remove or add your own.
  2. Pick a policy. Choose from the dropdown and tune parameters like the Round Robin quantum or the Feedback level quanta.
  3. Press run. Step through tick by tick, then check the Gantt table and metrics against your own hand-traced answer.

Ready to watch the scheduler work?

Load the built-in example or bring your own workload — the CPU is waiting.

No signup · Six policies · Step-by-step playback