linux/Documentation/scheduler/sched-deadline.rst

Imported from _research/manual-study-linux/file-notes/linux__Documentation__scheduler__sched-deadline.rst.md.

File Notes: Documentation/scheduler/sched-deadline.rst

Status: reviewed.

Purpose

Documents SCHED_DEADLINE: EDF scheduling augmented with CBS, runtime/deadline /period parameters, throttling, replenishment, GRUB reclaiming, and bandwidth management.

Key Points

SCHED_DEADLINE gives each task a runtime budget available within a deadline every period. CBS assigns scheduling deadlines and remaining runtime, throttles tasks that exhaust budget, and replenishes them at the appropriate time. EDF then picks the task with the earliest scheduling deadline.

GRUB bandwidth reclaiming separates active contending, active non-contending, and inactive states. Runqueues track active bandwidth (running_bw) and total bandwidth (this_bw) so blocked deadline tasks can move through reclaimable states without breaking guarantees.

Rust Translation Guidance

Make deadline reservations validated objects with runtime, deadline, period, remaining runtime, and state. Use typed admission checks and state transitions for contending/non-contending/inactive rather than ad hoc timers.

AI-Native Systems Guidance

Deadline scheduling is a good model for AI work with service-level objectives: bounded inference runtime per period, explicit deadline, admission control, and overrun signaling or degradation.

Evidence

• EDF plus CBS isolation is introduced at Documentation/scheduler/sched-deadline.rst:38-45.
• Runtime, period, deadline, CBS assignment, throttling, and replenishment are described at Documentation/scheduler/sched-deadline.rst:53-123.
• GRUB states and inactive timer behavior are documented at Documentation/scheduler/sched-deadline.rst:126-197.
• running_bw, this_bw, and reclaiming formula context appear at Documentation/scheduler/sched-deadline.rst:199-225.