VLM

How fast are LLM inference engines anyway? — Charles Frye, Modal

Jun 27, 2025 · 16:07

Charles Frye presents benchmarks from hundreds of runs on Modal comparing open-source inference engines VLM, SGLang, and TensorRTLM across models like Qwen 3 and Gemma 27B, arguing open weights models have caught up to proprietary ones, making self-hosting viable. He shows, for example, that Qwen 3 (MoE) on VLM achieves ~1 request/sec with 128 input tokens and 1024 output tokens, while switching to a RAG-like workload (1024 in, 128 out) yields a 4x throughput improvement. Frye warns that optimizing for context over reasoning can improve latency without sacrificing quality, and notes that the engines' out-of-the-box performance varies by model—e.g., SGLang underperforms VLM on Gemma due to less optimization. He also highlights the gap between prefill (parallel) and decode (autoregressive) speeds, which a rationalist would expect from transformer architecture. The benchmarks, available at modal.com/llmalmanac, aim to help engineers choose hardware and engines, with contributions welcome for optimized configs like TensorRTLM's knobs.

The GenAI Maturity Curve or You Probably Don't Need Fine Tuning: Kyle Corbitt

Feb 9, 2025 · 18:03

Kyle Corbitt, CEO of OpenPipe, argues that most teams don't yet need fine-tuning and should start with prompted models like GPT-4. He presents a GenAI maturity curve where the trigger to fine-tune is when you hit constraints on cost, latency, or quality consistency—for example, if GPT-4 is 80-90% correct but inconsistent on the last 10-20%. Fine-tuning shifts the paradigm frontier outward, enabling models like fine-tuned LLaMA 38B to outperform GPT-4 at 1/25th the cost. The process has four steps: capture production logs to know your input distribution, prepare high-quality data (using GPT-4 outputs or iterative labeling), train with one-click tools, and evaluate with inner-loop (LLM-as-judge) and outer-loop (business metrics) evals. OpenPipe and other providers make deployment trivial via OpenAI-compatible APIs. The talk delivers a concrete decision framework and a walkthrough so any engineer can fine-tune in under an hour.