What is MFU (Model FLOPs Utilization), and why can GPU utilization be misleading?
nvidia-smi reading 100% can mask the fact that you are tapping only a fraction of the hardware's real compute. What matters is MFU (useful FLOPs vs peak) and the gap between 'the GPU is busy' and 'the GPU is efficient'.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
nvidia-smi reading 100% can mask the fact that you are tapping only a fraction of the hardware's real compute. What matters is MFU (useful FLOPs vs peak) and the gap between 'the GPU is busy' and 'the GPU is efficient'.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
