Prevent priority work from starving maintenance forever
A continuous stream of interactive jobs keeps cache-maintenance tasks queued indefinitely.
- Focused work estimate
- 4h + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Scheduling · Fairness · Performance analysis
Estimated field mix
- Systems programming60%
- Performance engineering40%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
Review it, then add it to your workspace.
The board opens an editable draft; nothing is saved until you confirm it. Sign-in and workspace permissions apply, and Demo boards remain ephemeral.
Project context
A fictional image-indexing utility runs CPU-only synthetic jobs through a Rust worker pool. Its prototype loses wakeups, blocks shutdown, and treats cancellation as completion. Build a local library and deterministic concurrency harness; image content, GPU work, and production deployment are excluded.
Setup prerequisites
- Mutexes and condition variables
- Atomics
- Thread lifecycle
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
Acceptance criteria
- Scheduling policy defines a bounded wait for every admitted class
- Interactive latency remains measured under mixed load
- Class selection is deterministic for a declared seed
Implementation constraints
- Do not claim fairness from average completion time; report per-class tail wait.
Verification to include
- Replay a mixed workload and verify the declared service ratio.
- Saturate the interactive class and confirm maintenance still advances.
Deliverables
- Fair scheduler policy, simulator, and latency report
Rollout and recovery
Canary the policy in the synthetic workload and retain FIFO fallback.
Value of the work
For the engineer: Practice happens-before reasoning, ownership transfer, cancellation and liveness testing.
For the team: Review a worker primitive whose overload and shutdown behavior are predictable before it supports build or media workloads.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.