RDC Structural Checks: Interview Drills

Interview drills

Interview Drills for RDC Structural Checks focuses on unsafe reset crossing count, unresolved RDC warnings, waiver backlog. The goal is to convert issue observations into mechanism-backed closure decisions.

PROMPT
You see unsafe reset crossing count, unresolved RDC warnings, waiver backlog in RDC Structural Checks. Explain root cause and signoff decision.

STRONG ANSWER
1. Names crossing/reset class and context.
2. Explains RDC tools detect reset-origin and release-domain mismatches; violations must be triaged by intent, not mechanically waived.
3. Requests RDC structural report, reset intent annotation, waiver log.
4. Chooses fix/waiver/escalation with regression plan.

WEAK ANSWER
Lists tool commands or generic advice without mechanism and risk framing.

Diagram to draw on whiteboard

RDC structural classes

reset source A controls flop in domain B
            |
     release relationship legal?
        /             \
      yes             no
      pass          violation/waiver review

Debug tree to narrate

ROOT-CAUSE TREE — RDC Structural Checks

crossing failure observed
        |
   reproducible?
     /        \
   no          yes
   |            |
stress mode   classify issue
expansion       /      |      \
            synchronizer protocol reset/reconvergence
                 |         |           |
            MTBF fit    liveness    release ordering

CDC/RDC deep dive

Reset release ordering is a first-order reliability contract.

Concept diagram

RESET RELEASE FLOW

assert global -> clocks stable -> sync release per domain -> first transaction

Metric graph

BOOT STABILITY

passes per 1k boots: 920 -> 980 -> 999

Reports and artifacts

• reset dependency matrix

• RDC warning classes

• boot stress logs

• waiver aging

Mini case study

Domain B released before producer A was valid, causing rare startup deadlock.

Debug branches

• Correlate reset and clock timelines

• verify async assert/sync release

• exercise skewed release tests

Senior review question

Ask: what evidence proves this risk is closed for silicon, not just tool-clean?

Key takeaways

• State crossing class, assumptions, and owner with every issue.

• Run structural and dynamic regressions after each fix.

Common pitfalls

• Treating all warnings as equivalent risk.

• Waiving issues without containment evidence.

• Skipping reset and reconvergence stress after CDC fixes.

Principal CDC/RDC review addendum

RDC tools detect reset-origin and release-domain mismatches; violations must be triaged by intent, not mechanically waived.

Metric: unsafe reset crossing count, unresolved RDC warnings, waiver backlog