Key ideas
Long-context serving begins with cache-aware routing
A 200,000-token request should first be routed toward a replica that has both available prefill…Show moreShow less
A 200,000-token request should first be routed toward a replica that has both available prefill capacity and useful cached input. A cache hit can avoid recomputing part of the prompt, which reduces cost and time to first token. On some deployments, prefill and decode are disaggregated: one GPU group constructs the KV cache and produces the first token, then another group performs iterative decoding. A traffic-appropriate speculative model can accelerate the decode stage further.
Why it matters: Long-context performance depends as much on routing and cache placement as on raw model speed. Repeated agent or coding contexts can therefore be substantially cheaper than entirely novel prompts.
Supporting evidence
we want to send this one to something with number one available prefill workers and number two ideally some cached input already there so that we can skip prefill on at least part of these 200,000 tokens.