23. Which Scheduling Algorithm is Best?

There's no universal answer — it depends what you're optimizing for.

Goal Best Algorithm
Maximum CPU utilization	MLFQ, RR
Minimum turnaround time	SJF / SRTF
Minimum waiting time	SJF
Best response time	Round Robin, MLFQ
Fairness	Round Robin
Real-time guarantees	Priority (preemptive)
Batch processing	FCFS, SJF

What real OSes use: Linux → CFS (Completely Fair Scheduler, weighted fair queuing); Windows → multilevel priority queues with dynamic boosting; macOS → MLFQ-inspired with QoS classes; real-time Linux → POSIX real-time priority scheduling.

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