nano-vllm

Wed, 05 Nov 2025 15:29:19 +0800

GeeeekExplorer/nano-vllm

Nano-vLLM

A lightweight vLLM implementation built from scratch.

Key Features

🚀 Fast offline inference - Comparable inference speeds to vLLM
📖 Readable codebase - Clean implementation in ~ 1,200 lines of Python code
⚡ Optimization Suite - Prefix caching, Tensor Parallelism, Torch compilation, CUDA graph, etc.

Installation

`1`	`pip install git+https://github.com/GeeeekExplorer/nano-vllm.git`

Model Download

To download the model weights manually, use the following command:

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huggingface-cli download --resume-download Qwen/Qwen3-0.6B \
  --local-dir ~/huggingface/Qwen3-0.6B/ \
  --local-dir-use-symlinks False

Quick Start

See example.py for usage. The API mirrors vLLM’s interface with minor differences in the LLM.generate method:

from nanovllm import LLM, SamplingParams
llm = LLM("/YOUR/MODEL/PATH", enforce_eager=True, tensor_parallel_size=1)
sampling_params = SamplingParams(temperature=0.6, max_tokens=256)
prompts = ["Hello, Nano-vLLM."]
outputs = llm.generate(prompts, sampling_params)
outputs[0]["text"]

Benchmark

See bench.py for benchmark.

Test Configuration:

Hardware: RTX 4070 Laptop (8GB)
Model: Qwen3-0.6B
Total Requests: 256 sequences
Input Length: Randomly sampled between 100–1024 tokens
Output Length: Randomly sampled between 100–1024 tokens

Performance Results:

Inference Engine	Output Tokens	Time (s)	Throughput (tokens/s)
vLLM	133,966	98.37	1361.84
Nano-vLLM	133,966	93.41	1434.13

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