Multi-bit Crossing Strategies: Reports & Metrics

Reports and metrics

Reports & Metrics for Multi-bit Crossing Strategies focuses on coherency guarantee coverage, data corruption incidents, protocol overhead. The goal is to convert issue observations into mechanism-backed closure decisions.

Reports must explain risk movement in coherency guarantee coverage, data corruption incidents, protocol overhead, not just issue counts. A report is complete only when ownership and closure action are explicit.

Metric movement

METRIC TREND — coherency guarantee coverage, data corruption incidents, protocol overhead

critical open issues
  ^
  |                target (0 critical)
  |              - - - - - - - - - -
  |          o post triage
  |      o initial run
  |   o baseline
  +--------------------------------------> review iteration

Always pair count trend with evidence quality trend.

Risk distribution

RISK HEATMAP — Multi-bit Crossing Strategies

severity
high   |  XX  X
medium |  XXX XX
low    |  XXX XXX
        +----------------------------> ownership readiness
         unassigned   in-progress   closed

Metric focus: coherency guarantee coverage, data corruption incidents, protocol overhead

• Track coherency guarantee coverage, data corruption incidents, protocol overhead by block, mode, and severity.

• Separate structural warnings from behavior-proven hazards.

• Show waiver age and owner SLA alongside raw counts.

• Store evidence links with each closure claim.

CDC/RDC deep dive

Reconvergence failures are timing + logic coupling hazards.

Concept diagram

RECONVERGENCE

branch A sync --                 -> merge logic -> illegal combination window
branch B sync --/

Metric graph

HAZARD REPRODUCTION RATE

before fix: 1/2000 runs
after fix: 0/100000 runs

Reports and artifacts

• reconvergence warnings

• gray transition checks

• hazard replay traces

• multi-bit strategy map

Mini case study

Gray pointer was legal, but downstream merge decoded mixed-era values during burst stress.

Debug branches

• Trace fanin cones

• align event windows

• verify decode assumptions

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.

Reading evidence