Problems / LLM serving, hard
The app retries every failed model call 3 times immediately. When the token quota is hit, retries multiply the 429s.
Free to open. Runs in your browser, no sign-up.
Success ≥ 99%, time to first token p99 ≤ 2.5 s.
45 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 Model.Little's law: throughput ≈ concurrency ÷ latency. 200 slots at 50 ms serve about 4,000 req/s. | 3 replicas × 500 slots · timeout 30 s |
| ModelLLM endpoint | AI app calls it.Latency has two parts: time to the first token, then a steady stream of tokens per second. | 400 streams · 3.5M input tokens/min |
Try it first. Open one hint at a time if you get stuck.
Count model calls vs requests.
Retrying a 429 without backoff makes it worse.
Limit retries (1, with a budget), then fix the quota pressure.