Power Virus and Thermal Stress Testing: Worked Example

Worked example

Worked Example for Power Virus and Thermal Stress Testing is anchored on Worst-case sustained power, hotspot temperature, throttling onset, and recovery behavior under stress kernels.. Convert measurements into mechanism-backed decisions with clear owner accountability.

A regression appears in Worst-case sustained power, hotspot temperature, throttling onset, and recovery behavior under stress kernels.. Strong closure isolates first failing stage, proves mechanism, applies one reversible fix, and validates blast radius before release.

Execution lens

ACCELERATOR EXECUTION FLOW - Power Virus and Thermal Stress Testing

request ingress and model metadata
      |
      v
graph lowering and kernel selection
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      v
tile/dataflow scheduling and memory placement
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      v
tensor execution + synchronization barriers
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      v
result assembly + quality/SLA validation
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      v
release decision and rollback guardrails

Decision matrix

EVIDENCE MATRIX - Power Virus and Thermal Stress Testing

+-----------------------------+--------------------------------+--------------------------------+---------------------------+
| Evidence                    | Tells you                      | Does not prove                 | Next action               |
+-----------------------------+--------------------------------+--------------------------------+---------------------------+
| occupancy + timeline traces | where utilization is lost      | precise root cause             | map to memory and schedule|
| cache/SRAM/bandwidth stats  | data movement pressure         | model-level quality impact     | correlate with quality run|
| counter + profile alignment | bottleneck class confidence    | rollout safety                 | run full regression matrix|
| thermal/power telemetry     | sustained operating envelope   | correctness closure            | pair with verification    |
| before/after scenario pack  | mitigation movement            | long-tail stability            | execute guardrail replay  |
+-----------------------------+--------------------------------+--------------------------------+---------------------------+

AI accelerator deep dive

Bring-up speed and correctness depend on designed-in observability and replayable debug flow.

Concept diagram

BRING-UP EVIDENCE LOOP

failure symptom -> trace packet -> replay -> isolate root cause -> bounded fix

Metric graph

OBSERVABILITY VALUE

directed tests only      ██████████
plus counters            ███████
plus trace and replay    ███

Metrics and artifacts to collect

• counter completeness

• trace trigger coverage

• replay success rate

• escape-risk trend

Mini case study

A silicon-only regression closed quickly because trace identity and counter alignment were planned before tapeout.

Debug branches

• Start from first failing trace window

• Align software and hardware timestamps

• Demand reversible owner fix before signoff

Senior review question

Ask: which first-principles bottleneck class explains the symptom, and what artifact proves it reproducibly?

Key takeaways

• Tie every accelerator claim to a reproducible workload slice and one primary metric trend.

• Prefer bounded fixes with clear owner and rollback boundary over broad tuning bundles.

Common pitfalls

• Optimizing synthetic kernels without production-shape validation.

• Reading average latency while ignoring p95 and p99 behavior.

• Declaring sparse or precision wins without fallback and quality evidence.

Worked-example reasoning

Suppose Worst-case sustained power, hotspot temperature, throttling onset, and recovery behavior under stress kernels. regresses only under burst traffic. The shallow response is clock scaling. The stronger response is to inspect queueing, mapping, and memory-pressure interactions first.

If occupancy drops with high memory stalls, prioritize locality and scheduling fixes. If occupancy remains high with latency spikes, inspect contention and fairness policy.

Pick one bounded change per hypothesis and validate against baseline artifacts.