XDV Cross-Domain Scheduler

Version: 0.1.1 Status: active-split Language: Dust Programming Language (DPL)

Specification Alignment

• Primary: XDV-012 (Cross-Domain Scheduler)
• Reference: XDV-082 (Cross-Domain Scheduler Reference)

Purpose

xdv-cds is the deterministic arbitration engine for K/Q/Phi scheduling in XDV. It provides:

• policy-driven deterministic arbitration,
• replay-stable ordering keys,
• starvation and fairness constraint validation.

Scope Implemented in 0.1.1

• Deterministic arbitration API with policy plug-ins:
  • round-robin, priority, EDF, coherence-aware, domain-fair.
• Replay-stable ordering:
  • deterministic order key generation,
  • replay match/mismatch validation.
• Fairness enforcement helpers:
  • starvation detection,
  • fairness skew validation,
  • combined scheduler constraint validator.

Public Surface

Core module: src/cds.ds

Key APIs:

• arbitrate_next_domain(...)
• schedule_tick_with_policy(...)
• schedule_tick_replay(...)
• compute_replay_order_key(...)
• validate_starvation_constraints(...)
• validate_fairness_constraints(...)
• validate_scheduler_constraints(...)

Version APIs:

• xdv_cds_interface_version_major()
• xdv_cds_interface_version_minor()
• xdv_cds_interface_version_patch()
• xdv_cds_arbitration_api_version()
• xdv_cds_replay_api_version()
• xdv_cds_fairness_api_version()

Repository Layout

• src/: implementation, stable interface, tests
• docs/: architecture and contract docs
• tests/: standalone test suite placeholders
• State.toml: workspace manifest
• changelog.md: release notes

Build

cargo run --manifest-path dust/Cargo.toml -- check xdv-cds/src

Integration Notes

• xdv-kernel consumes xdv_cds_interface_version_* from this project.
• Arbitration and fairness decisions are deterministic and replay-compatible by construction.