Problems / LLM serving, medium
A voice assistant transcribes speech, answers, and speaks the reply. Speech-to-text has 16 slots at 30 utterances a second.
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Success ≥ 99%, p99 ≤ 5 s.
Like a coding problem, a solution has to pass every case, not just the one it was built for. Submit in the lab runs all 6; 2 of them are hidden until then.
30 requests a second for 30 seconds: 100% request (reads).
What each component does in this design, and what calls it. The simulator mimics each one from these settings.
| Component | Its job here | Settings |
|---|---|---|
| Load balancerLoad balancer | Traffic enters here.Calls AI app.Layer 4 balancers route by IP and port; layer 7 balancers read HTTP and can route by path or header. | – |
| AI appApp service | Load balancer forwards to it.Calls Speech to text, GPU serving pool, Text to speech.Little's law: throughput ≈ concurrency ÷ latency. 200 slots at 50 ms serve about 4,000 req/s. | 3 replicas × 500 slots · timeout 30 s |
| Speech to textSpeech to text | AI app calls it.Streaming speech recognition returns partial words while the user is still talking. | 16 slots · 6,000 calls/min |
| GPU serving poolSelf-hosted serving pool | AI app calls it.GPU servers batch requests together; throughput rises with batch size until memory runs out. | 400 slots |
| Text to speechText to speech | AI app calls it.Speech synthesis can start playing before the whole sentence is generated. | 200 slots · 6,000 calls/min |