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Equation 1 · Part 2 · How AI Inference Serving Actually Works

addition

t+1t+1
addition

What this part means

Add the term after the plus sign to the term or group before it.

Its job in the formula

Add the term after the plus sign to the term or group before it.

The passage around this formula

That fact is that a request has two phases with different physics, and the split is not incidental to the architecture — it follows directly from what autoregressive generation requires. Prefill consumes the entire prompt in one pass. Every position in the prompt is known in advance, so the accelerator computes attention and feed-forward outputs for all of them at once, as one large, dense matrix multiplication. Decode then produces the answer one token at a time, and each step depends on the one before it: the model cannot compute position t+1 until it has sampled position t , so there is no way to parallelize across output positions the way prefill parallelizes across input positions. The…

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Learn the underlying idea

Addition combines quantities; subtraction measures the signed difference between them. Parentheses show what is combined before the rest of the expression is evaluated.

Open the illustrated addition and subtraction in an equation guide →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.