Open-source tool for tuning inference servers: 81 → 421 tok/s on RTX 5090, 257 → 490 tok/s on H100, cost down 81% / 48%
Hello everybody,
I built Profile to make inference tuning deterministic, and save us all time. v2.2 is out today.
It reads a live vLLM server's metrics, compares them against the GPU's roofline ceiling, and names the bottleneck with the exact flag to change.
You apply, it re-measures, and prints before/after on every metric. Regressions get labeled worse, not buried. It never touches the server: no restarts, no config writes, no synthetic load.
Two runs on record, both real SWE-Bench agent traffic, no synthetic benchmarks:
RTX 5090, muse-glimmer 30B, 4 iterations:
- 81 → 421 tok/s at 25k ctx
- $3.41 → $0.65 per 1M output tok
- TTFT 224ms (p95 500ms) at end of run
- 4.72 → 1.08 J/tok
H100 80GB, Qwen3.8-27B, 3 iterations:
- 257 → 490 tok/s at 27k ctx
- $3.23 → $1.69 per 1M output tok
- TTFT 1.9s → 539ms (p95 4.2s → 1.9s)
- 2.39 → 1.00 J/tok
The honest part: on the H100 I scaled agents 10 → 285 without fixing KV first. TTFT exploded to 172s. Profile labeled it worse, named KV pressure, and the fix (fp8 KV, ctx trim, seat cut 345 → 22) recovered the run.
Both journeys on video: https://jungledesh.github.io/profile/journeys.html
Note: vLLM only today, more engines next. Single GPU, NVIDIA or AMD; multi-GPU / TP is next on the roadmap.
If you run vLLM in prod, tell me what it names on your servers, and where it's wrong.
curl --proto '=https' --tlsv1.2 -LsSf \
https://github.com/jungledesh/profile/releases/latest/download/profile-installer.sh | sh
profile diagnose --url http://localhost:8000/metrics --duration 2m
GitHub: https://github.com/jungledesh/profile
Docs: https://jungledesh.github.io/profile/docs.html