PCIe/CXL Deep Dive · All levels

Advanced Error Reporting (AER): Review Checklist

Review Checklist for Advanced Error Reporting (AER).

Review checklist

Review Checklist for Advanced Error Reporting (AER) focuses on Correctable error rate, uncorrectable error escalation time, and AER mask effectiveness. The purpose is to turn memory observations into mechanism-backed actions with explicit owners and release-safe validation.

  • Workload scope and SLA targets are explicit.

  • Environment tags are locked and reproducible.

  • First failing transition is proven by command-level evidence.

  • Owner and rollback criteria are documented.

  • Validation matrix covers performance, stability, and reliability.

  • Owners signed: reliability owner, firmware owner, driver owner, validation owner.

PCIe/CXL deep dive

RAS closure maps AER, poison, and surprise-down events to bounded containment and recovery actions.

Concept diagram

diagram
RAS ESCALATION

detect -> classify -> contain -> recover -> validate

Metric graph

diagram
RAS EVENT MIX

correctable trend   ███████
uncorrectable       ██
surprise-down       █

Reports and artifacts

  • AER register dump

  • poison injection log

  • surprise-down timeline

  • containment action record

Mini case study

Masked correctable errors accumulated until a surprise-down during peak traffic forced unplanned failover.

Debug branches

  • Separate CE trend from UE containment paths

  • Validate poison handling end-to-end

  • Test surprise-down drain and driver recovery

Senior review question

Ask: which latency, bandwidth, and reliability evidence proves this PCIe/CXL topic is closed under real traffic?

Key takeaways

  • Always tie controller and PHY counter shifts to application latency and throughput outcomes.

  • Lock firmware timing profile, thermal condition, and DIMM state before comparing PCIe/CXL captures.

Common pitfalls

  • Chasing peak bandwidth while ignoring p99 latency and fairness tails.

  • Changing timing guardbands without separating SI noise from scheduling issues.

  • Declaring closure without reliability gates, fault injection, and regression replay.

Review checklist explanation

A checklist here protects against false closure. Every item should map to a known memory failure mode.

For Advanced Error Reporting (AER), minimum checklist: workload scope, Correctable error rate, uncorrectable error escalation time, and AER mask effectiveness, artifact evidence (AER register dump, error source tree, and escalation timeline), bottleneck class, owner, rollback path, and corner-matrix validation.

If controller or firmware changed, include fairness and RAS checks. If PHY or package assumptions changed, include SI/PI and thermal guardband evidence.