CDC / RDC · All levels

RDC Structural Checks: Comparison Matrix

Comparison Matrix for RDC Structural Checks.

Comparison matrix

Reset strategies trade simplicity, safety margin, and bring-up time.

diagram
+------------------+----------------+----------------+----------------+
| Approach         | Strength       | Weakness       | Best when      |
+------------------+----------------+----------------+----------------+
| Conservative     | safe           | extra latency  | high-risk crossings |
| Balanced         | practical      | more setup     | most production paths |
| Aggressive       | fast schedule  | escape risk    | late-stage crunch |
| Refactor         | structural gain | long cycle     | recurring failures |
+------------------+----------------+----------------+----------------+

When to choose each approach

  • Select approach by silicon risk, not only schedule urgency

Interview traps

  • Global waiver spray

  • Unproven protocol assumptions

Evidence comparison

diagram
CDC/RDC EVIDENCE MATRIX — RDC Structural Checks

+-----------------------+----------------------------+----------------------------+---------------------------+
| Evidence              | Tells you                  | Does not prove             | Next action               |
+-----------------------+----------------------------+----------------------------+---------------------------+
| structural report     | crossing topology class    | protocol liveness          | add assertions/formal     |
| reset map             | release dependencies       | dynamic startup behavior   | run reset stress tests    |
| formal proof          | bounded safety/liveness    | real firmware sequence     | correlate with simulation |
| simulation stress     | observed mode behavior     | full state-space closure   | target unhit corners      |
| waiver log            | accepted residual risk     | technical correctness      | periodic revalidation     |
+-----------------------+----------------------------+----------------------------+---------------------------+

CDC/RDC deep dive

Reset release ordering is a first-order reliability contract.

Concept diagram

diagram
RESET RELEASE FLOW

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

Metric graph

diagram
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