---
license: apache-2.0
library_name: scikit-learn
tags:
  - quantile-regression
  - scheduling
  - systems
  - llm-serving
  - nsdi
---

# JITServe QRF Length Predictor

This repository provides the **pretrained QRF (Quantile Regression Forest) length predictor**
used by **[JITServe (NSDI’26)](https://arxiv.org/abs/2504.20068)** to estimate conservative upper bounds on LLM output lengths.

This predictor is:
- **Not an LLM evaluation model**
- **Not fine-tuned during inference**
- A lightweight **offline-trained prediction model** used solely for scheduling decisions

It is released to ensure **full reproducibility** of the JITServe artifact.

---

## What Is Included

This repository contains two components that must be used together:

```text
qrf_model/
  ├── 0_qrf_lmsys_chat_llama3_8b.pkl
  └── 0_qrf_lmsys_chat_qwen25_7b.pkl

qrf_vectorizer/
  ├── 0_qrf_lmsys_chat_llama3_8b.pkl
  └── 0_qrf_lmsys_chat_qwen25_7b.pkl
```

## Usage

These artifacts are consumed by JITServe at runtime.

Expected directory layout in the JITServe artifact:
```
assets/qrf/
├── qrf_model/
└── qrf_vectorizer/
```

After downloading this repository, place its contents under the path above.

JITServe loads the predictor automatically during startup and does not require
any additional configuration by default.

## Citation
If you use these artifacts, please consider to cite our paper:
```
@misc{zhang2025jitservesloawarellmserving,
      title={JITServe: SLO-aware LLM Serving with Imprecise Request Information}, 
      author={Wei Zhang and Zhiyu Wu and Yi Mu and Rui Ning and Banruo Liu and Nikhil Sarda and Myungjin Lee and Fan Lai},
      year={2025},
      eprint={2504.20068},
      archivePrefix={arXiv},
      primaryClass={cs.DC},
      url={https://arxiv.org/abs/2504.20068}, 
}
```