Strong answers run metric, mechanism, experiment, fix, regression and release judgment. Tools and commands without that decision logic score as junior.
Each phase earns one or two sentences. Brevity with numbers beats a long mechanism tour that never names an experiment.
Phase | One sentence that earns it |
|---|---|
Metric | Workload, baseline and the delta in product units |
Mechanism | Two ordered hypotheses with the counters behind each |
Experiment | Cheapest test that falsifies the leader |
Fix and guardrails | Change, PPA cost, regression surface and rollback trigger |
As metric, mechanism, experiment, fix, regression and release judgment. Each phase carries numbers, and the experiment is the cheapest test that kills the leading hypothesis.
Naming workload and baseline first, proposing the cheapest experiment before any design change, and stating PPA and verification impact for every fix.
A staff architect owns cross-block budgets, methodology and the signoff narrative. Technical trivia without ownership logic stays senior, never staff.
Debug loops close with artifacts. Mechanism, evidence, bounded fix, regression coverage and an owner-approved decision end the loop; silence never does.
Staff owns cross-block budgets, methodology, escalation paths and the signoff story across teams. Senior owns block depth. Trivia depth without cross-team ownership is not staff evidence.
Dominant limiter, competing hypothesis, falsification evidence, chosen fix and regression checks, each with an owner. A counter dump without a decision and an owner is not a memo.
They ship a mechanism-backed fix with telemetry guardrails, regression coverage and explicit signoff criteria tied to product KPIs. Metrics looking better is an observation, not a closure.
Escalation follows stalled ownership, not discomfort. Escalate when fixes cross architecture, compiler, firmware or physical-design boundaries and local optimization stalls.
Overfit guards apply to every tuning claim. Holdout workloads, long runs and multi-KPI gates decide rollout, never short benchmark loops.
When the fix crosses ownership boundaries and local optimization stalls despite an isolated mechanism. Escalating before isolating a concrete mechanism is premature.
Holdout workloads outside the tuning set, long-duration runs with thermal and voltage variation, and multi-KPI acceptance gates. Short-loop gains alone never roll out.
Decisions resting on authority or optimism instead of shared metrics, evidence and explicit risk ownership. Naming that drift is itself a senior move.
Performance-per-watt check from stated parameters
formula: perf_per_watt_ratio = perf_ratio / power_ratio
example: 5 percent higher frequency for 12 percent higher power
result: 1.05 / 1.12 = 0.9375, about 6 percent worse perf per wattThe mechanism and its falsification evidence. Without them there is no regression surface, no guardrail and no safe signoff, only luck awaiting a new workload.