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Design the evaluation you run against a serving deployment, not against a model.

Model evaluations answer whether the weights are good and deployment evaluations answer whether your configuration serves them correctly, which is a different and more common failure. What to sample, why category averages hide the regressions that matter, and the reference that makes a result mean something.

Updated Sep 2026 · Grounded in real AI infrastructure interview loops and written to a senior-engineer editorial bar, with every number worked and every diagram hand-built.

Model evaluations answer whether the weights are good and deployment evaluations answer whether your configuration serves them correctly, which is a different and more common failure. What to sample, why category averages hide the regressions that matter, and the reference that makes a result mean something.

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Foundational
🧮 Open Weights & Serving Engines
Serving Benchmarks That Do Not LieMost published serving numbers are not comparable to each other and not predictive of production, because they differ in the input distribution, the concurrency, whether the cache was warm, and which of several very different metrics is being reported. A benchmark that supports a decision has to fix all four, report a distribution rather than a mean, and be run against the traffic shape you actually serve. The single most useful discipline is to compute the bandwidth bound first, so you know what fraction of the possible you achieved.
Foundational
🧮 Open Weights & Serving Engines
vLLM Server Arguments That MatterA vLLM deployment is mostly decided by a dozen flags, and the ones that matter fall into four groups: how the model is split across GPUs, how memory is divided between weights and cache, how requests are batched, and which specialized backends the model needs. Getting the first two wrong produces an engine that will not start or that runs out of memory under load. Getting the third wrong produces an engine that starts, serves, and misses its latency target by a wide margin.
Foundational
🧮 Open Weights & Serving Engines
SGLang Server Arguments That MatterSGLang's tuning model is different from vLLM's in one way that matters: it exposes the scheduler's aggressiveness and the static memory fraction as direct knobs, and its own documentation gives target values for the runtime signals those knobs move. That makes tuning it a measurement loop rather than guesswork. Aim for a queue of a hundred to a couple of thousand requests, token usage above 0.9, and five to eight gigabytes of free GPU memory after startup, then adjust the flags that move each one.
Foundational
🧮 Open Weights & Serving Engines
Multi-Node Serving TopologiesOnce a model needs more GPUs than one NVLink domain holds, the deployment shape becomes a real design decision. Tensor parallelism stays inside the node because it communicates twice per layer per token. Across nodes the choices are data parallelism with replicas, pipeline parallelism with a bubble, expert parallelism with an all-to-all, or disaggregation that runs prefill and decode on separate pools and ships the KV cache between them. Each has a different failure mode and a different scaling story.
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FEDITOR'S NOTE

Scored on evaluating the configuration rather than the weights, on per-category scoring against a reference, and on sampling from production rather than from a public set.

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