Sequential Equivalence: Latency-Aware Proofs Across Micro-Architectural Changes: Reports and Metrics

Reports and metrics

Reports and Metrics for Sequential Equivalence: Latency-Aware Proofs Across Micro-Architectural Changes is anchored on non-vacuous closure rate, counterexample turnaround, and residual-risk trend by requirement class. Convert outcomes into assumption-aware, evidence-backed actions.

A useful report explains why closure quality moved, not only that status changed.

Evidence matrix

EVIDENCE MATRIX - Sequential Equivalence: Latency-Aware Proofs Across Micro-Architectural Changes

+-----------------------------+--------------------------------+--------------------------------+---------------------------+
| Evidence                    | Tells you                      | Does not prove                 | Next action               |
+-----------------------------+--------------------------------+--------------------------------+---------------------------+
| property status by class    | closure shape by requirement   | model realism                  | pair with cover reachability |
| vacuity and trigger checks  | assertion meaningfulness       | full legal-path exploration    | inspect assumptions       |
| counterexample traces       | concrete divergence path       | complete bug-space closure     | classify and replay       |
| assumption audit trail      | model boundary confidence      | implementation correctness     | review spec traceability  |
| before/after trend packet   | mitigation movement quality    | long-window stability          | run broader matrix        |
+-----------------------------+--------------------------------+--------------------------------+---------------------------+

• Track non-vacuous closure rate, counterexample turnaround, and residual-risk trend by requirement class by requirement class and risk tier.

• Include assumption and tool metadata in every report header.

• Correlate status with vacuity and cover reachability movement.

• Call out contradictory evidence explicitly.

Formal deep dive

Equivalence confidence comes from transformation-aware setup and rapid first-divergence diagnosis.

Concept diagram

EQUIVALENCE WORKFLOW

golden and revised design -> mapping and alignment -> mismatch triage -> closure evidence

Metric graph

LEC/SEC DEBUG SIGNALS

setup mismatches        █████
real behavioral deltas  ███
resolved divergences    ███████

Metrics and artifacts to collect

• compare-point match quality

• SEC latency-alignment success

• RTL-to-gate variant coverage

• ECO mismatch root-cause aging

Mini case study

A late ECO mismatch was traced to clock-gating setup, then closed with repeatable SEC alignment rules.

Debug branches

• Classify mismatch source before editing waiver sets.

• Use SEC when latency movement is intentional.

• Replay first divergence in simulation for cross-validation.

Senior review question

Ask: which requirement intent is proven, under which assumptions, and what residual risk remains?

Key takeaways

• Tie each proof claim to assumption boundaries and reachability evidence.

• Prefer minimal reversible fixes and preserve legal behavior visibility.

Common pitfalls

• Treating runtime reduction as proof-quality improvement without audits.

• Declaring closure while critical covers remain unreachable.

• Using broad waivers instead of first-divergence root-cause ownership.

Report interpretation

Report status with vacuity, cover reachability, and assumption influence side by side.

Promote only when trend data supports reproducible closure behavior.