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Design a roofline-based performance model that predicts TTFT and TPOT for any model, GPU and batch. Where will it be wrong?

Twenty lines of roofline arithmetic get within striking distance of a real server, and the interviewer knows it. What they are scoring is the list of places the model breaks, and how you would catch each one before a capacity plan rests on it.

Updated Oct 2026 · Worked answers on inference mechanisms, with calculations, implementation details, and follow-up questions.

Twenty lines of roofline arithmetic get within striking distance of a real server, and the interviewer knows it. What they are scoring is the list of places the model breaks, and how you would catch each one before a capacity plan rests on it.

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