Code RoomLLM inference serving with batching
HardPrep Room Coding #4606

LLM inference serving with batching

System designML systemsSenior–Staff~45 min

Design an LLM-inference-serving system for a 70B-parameter model behind a public API with continuous (in-flight) batching. Requests are streaming chat completions with highly variable input and output lengths (some 50 tokens, some 4,000). You must maximize GPU throughput (tokens/sec/dollar) while honoring a per-request time-to-first-token SLO of 500ms p95 and a smooth token streaming rate. Traffic is bursty, the model needs multiple GPUs (tensor/pipeline parallel), and you serve a mix of short interactive and long-generation requests on the same fleet.

What a strong answer looks like

Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts (data model, bottlenecks, consistency, failure modes) and name the trade-offs you are making.

Clarify5:00 left
Estimate5:00 planned
Design15:00 planned
Deep dive12:00 planned
Failure8:00 planned
0:00
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.