timeslicebased

Timeslicebased refers to a design principle in which access to a shared resource, most commonly the central processing unit, is controlled in fixed-length intervals called time slices or quanta. In a timeslicebased system, a scheduler assigns a slice to a ready task and enforces preemption when the slice ends, switching to another task in a deterministic manner.

In operating systems, timeslice-based scheduling is a core method of preemptive multitasking. A ready queue of processes is rotated, with each task receiving CPU time for a quantum. When the quantum expires, a context switch occurs and the scheduler selects the next task. The approach aims to balance responsiveness for interactive tasks with overall system throughput.

Variants include static quanta, where all tasks receive the same slice length, and adaptive quanta, where the slice length may vary based on task behavior, priority, or system load. Round-robin exemplifies a common static-timeslice policy, while multilevel feedback queues adjust slices to favor short, interactive tasks while still serving longer-running jobs.

Timeslice concepts also appear in other domains, such as time-division multiplexing in communications, where a channel is divided into time slots; in virtualization, virtual CPUs are scheduled on physical cores in time slices; and in web browsers, work may be partitioned into chunks to maintain UI responsiveness.

Key trade-offs include context-switch overhead versus responsiveness. Too-short slices raise switching costs and may reduce throughput, while too-long slices increase latency for interactive tasks. Real-time systems may require timing guarantees beyond generic timeslice fairness, favoring fixed deadlines and priority-based scheduling when necessary.