GPU Design · All levels
GPU Physical Design & Power: Tricky Q&A
Senior interview and review questions for GPU Physical Design & Power.
Section Q&A bank
Use these drills after completing all topics in GPU Physical Design & Power. Answer with workload context, mechanism proof, artifact, owner, and release decision.
Why is SM cluster placement tightly coupled to memory-system performance?
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[INT][GPU][GPU-PHYSICAL-DESIGN]
Q: Why is SM cluster placement tightly coupled to memory-system performance?
A:
Floorplan distance and routing congestion shape latency and bandwidth consistency between SM arrays, caches, and memory interfaces.
FOLLOW-UP TRAP: Optimizing compute floorplan independent of memory proximity.How do thermal hotspots distort timing closure assumptions?
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[INT][GPU][GPU-PHYSICAL-DESIGN]
Q: How do thermal hotspots distort timing closure assumptions?
A:
Temperature gradients shift delay and skew behavior, causing corner-specific path failures not visible in uniform thermal assumptions.
FOLLOW-UP TRAP: Relying on nominal thermal models for final closure.What confirms DVFS policy is helping instead of masking design issues?
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[INT][GPU][GPU-PHYSICAL-DESIGN]
Q: What confirms DVFS policy is helping instead of masking design issues?
A:
Performance-per-watt improves while throttle duty cycle and reliability margins remain within signed guardbands across stress workloads.
FOLLOW-UP TRAP: Judging DVFS by average frequency alone.When should clock/power partitioning be revisited?
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[INT][GPU][GPU-PHYSICAL-DESIGN]
Q: When should clock/power partitioning be revisited?
A:
When crossing violations, control complexity, or wake/transition instability repeatedly block timing or integration closure.
FOLLOW-UP TRAP: Adding constraints without reevaluating partition boundaries.Q&A drill guide
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WORKLOAD -> BOTTLENECK -> METRIC -> CHANGE -> REGRESSIONSketch while answering
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GPU PD VIEW
HBM edges + SM clusters + cache rings + power/clock gridKey takeaways
Always pair micro-kernel metrics with end-to-end workload impact.
Lock toolchain, driver, and launch metadata before comparing performance results.
Common pitfalls
Optimizing occupancy without checking memory-system saturation.
Comparing profiler captures from different driver or compiler builds.
Declaring wins without reproducible accuracy and performance gates.