Reports and metrics

Reports & Metrics for Scenario: SerDes Bring-up Collapse focuses on L0 bring-up pass rate, BER spikes, retrain frequency. The goal is to connect observed symptom to boundary mechanism, ownership, and signoff risk.

Reports convert L0 bring-up pass rate, BER spikes, retrain frequency into release decisions. A single average metric is insufficient; use tails, mode breakdowns, and trend under controlled conditions.

Metric movement

METRIC GRAPH — L0 bring-up pass rate, BER spikes, retrain frequency

health / margin
  ^
  |                         target
  |                       - - - - - - -
  |                  o post-fix
  |              o
  |         o baseline
  |    o failing run
  +--------------------------------------> debug iteration
    repro setup    root-cause proof    release candidate

Readout:
  - compare only equivalent mode, payload, clock, and environment tags
  - separate symptom stabilization from true mechanism closure

Distribution view

METRIC DISTRIBUTION — Scenario: SerDes Bring-up Collapse

occurrence
  |      ***
  |    *******
  |  ***********
  |*************  <- left tail (worst boundary excursions)
  +--------------------> margin / stability / error metric
  bad                 nominal

Fix the tail first; average value can hide integration escapes.

• Track L0 bring-up pass rate, BER spikes, retrain frequency by mode and stress condition.

• Report p95/p99 or worst-case tail when intermittent escapes matter.

• Store metric with exact artifact and configuration tags.

• Separate symptom stabilization from mechanism closure.

AMS deep dive

Senior interview answers must show mechanism, ownership, and regression discipline.

Concept diagram

INTERVIEW LADDER

symptom -> mechanism -> evidence -> owner -> bounded fix -> regression

Metric graph

ANSWER QUALITY

mechanism depth ██████
evidence usage  █████
ownership clarity ████

Reports and artifacts

• mock interview rubric

• scenario response score

• evidence completeness

• regression-plan quality

Mini case study

Candidate fixed the symptom but failed to define a regression matrix and ownership map.

Debug branches

• Name first failing boundary

• State one proving artifact

• Propose one bounded reversible fix

Senior review question

Ask: what boundary condition proves this topic is actually closed?

Key takeaways

• State boundary, mode, and evidence tag with every claim.

• Always align analog, digital, and physical owners before signoff decisions.

Common pitfalls

• Fixing averages while tails still fail.

• Skipping package/supply evidence in jitter or SerDes issues.

• Shipping with waivers that lack owner and expiration criteria.

Reading reports