KTransformers Fine-Tuning × LLaMA-Factory Integration

Introduction

From DeepSeek-V3/R1 to Qwen3-MoE and Kimi-K2, each wave of open-sourced large models brings leaps in performance and scale. However, many researchers and developers are constrained by expensive GPUs and models with tens or even hundreds of billions of parameters, making it hard to fine-tune very large models under limited resources. To bridge this gap, we propose a practical approach: combining KTransformers with LLaMA-Factory. With just 2–4 RTX 4090s and a high-memory CPU, you can fine-tune ultra-large MoE models like DeepSeek-671B.

Our goal is to give resource-constrained researchers a local path to explore fine-tuning ultra-large models, and also a fast way to customize smaller models (e.g., 14B/30B) for specific scenarios. We validate the setup using stylized dialogue, Westernized translation tone, and medical Q&A as representative tasks, showing that personalized adaptation can be achieved within hours.

As shown below, LLaMA-Factory is the unified orchestration/configuration layer for the whole fine-tuning workflow—handling data, training scheduling, LoRA injection, and inference interfaces. KTransformers acts as a pluggable high-performance backend that takes over core operators like Attention/MoE under the same training configs, enabling efficient GPU+CPU heterogeneous cooperation.

Within LLaMA-Factory, we compared LoRA fine-tuning with HuggingFace, Unsloth, and KTransformers backends. KTransformers is the only workable 4090-class solution for ultra-large MoE models (e.g., 671B) and also delivers higher throughput and lower GPU memory on smaller MoE models (e.g., DeepSeek-14B).

† 1400 GB is a theoretical BF16 full-parameter resident footprint (not runnable). 70 GB is the measured peak with KT strategy (Attention on GPU + layered MoE offload).

Fine-Tuning Results

Stylized Dialogue (CatGirl tone)

Dataset: NekoQA-10K. Goal: improve style consistency and recognizability.

The figure compares responses from the base vs. fine-tuned models. The fine-tuned model maintains the target tone and address terms more consistently (red boxes), validating the effectiveness of style-transfer fine-tuning.

Benchmarks

We use:

(1) Translational-Style-ChatLLM, which asks for an exaggerated, Westernized translation tone—clear, stylized customization.

(2) AfriMed-QA (ACL 2025), a medical dataset for African contexts with strong domain specificity, including multiple-choice and short-answer sub-tasks—well-suited for vertical fine-tuning evaluation.

The tables show metrics before vs. after LoRA fine-tuning. We observe large improvements across metrics, verifying fine-tuning effectiveness:

Even for ultra-large MoE models, KTransformers-backed fine-tuning achieves strong task performance quickly.

Quick to Start

This section shows how to install and use LLaMA-Factory + KTransformers for fine-tuning and inference:

• Environment setup
• Fine-tune ultra-large MoE models with KTransformers backend
• Load the fine-tuned model (base + LoRA adapter) for chat/inference
• Batch inference and metric evaluation

Environment Setup

According to the following example, install both the KTransformers and LLaMA-Factory environments simultaneously. This time, to simplify the installation process of KTransformers, we have specially packaged a wheel file to avoid local compilation. The detailed installation steps are as follows: (Note: Make sure your local Python version, Torch version, CUDA version, and the KTransformers wheel filename correspond correctly.)

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# 1. Create a conda environment
conda create -n Kllama python=3.10 # choose from : [3.10, 3.11, 3.12, 3.13]
conda install -y -c conda-forge libstdcxx-ng gcc_impl_linux-64
conda install -y -c nvidia/label/cuda-11.8.0 cuda-runtime

# 2. Install the LLaMA-Factory environment
git clone --depth 1 https://github.com/hiyouga/LLaMA-Factory.git
cd LLaMA-Factory
pip install -e ".[torch,metrics]" --no-build-isolation

# 3. Install the KTransformers wheel that matches your Torch and Python versions (Note: The CUDA version can differ from that in the wheel filename.), from https://github.com/kvcache-ai/ktransformers/releases
pip install ktransformers-0.4.1+cu128torch28fancy-cp310-cp310-linux_x86_64.whl

# 4. Install flash-attention, download the corresponding file based on your Python and Torch versions from: https://github.com/Dao-AILab/flash-attention/releases
pip install https://github.com/Dao-AILab/flash-attention/releases/download/v2.8.3/flash_attn-2.8.3+cu12torch2.8cxx11abiTRUE-cp310-cp310-linux_x86_64.whl
# abi=True/False can find from below
# import torch
# print(torch._C._GLIBCXX_USE_CXX11_ABI)

# 5. (Optional) If you want to use flash_infer (otherwise it defaults to triton)
git clone https://github.com/kvcache-ai/custom_flashinfer.git
pip install custom_flashinfer/

Usage tip: In LLaMA-Factory YAML, set use_kt: true and pick a kt_optimize_rule file to have KTransformers handle the core compute. The features below show typical configs.

Core Feature 1: Use KTransformers backend to fine-tune ultra-large MoE models

Run the command: USE_KT=1 llamafactory-cli train examples/train_lora/deepseek3_lora_sft_kt.yaml.

Note: You must provide a BF16 model. DeepSeek-V3-671B is released in FP8 by default; convert with DeepSeek-V3/inference/fp8_cast_bf16.py.

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### model
model_name_or_path: opensourcerelease/DeepSeek-V3-bf16
trust_remote_code: true

### method
stage: sft
do_train: true
finetuning_type: lora
lora_rank: 8
lora_target: all

### dataset
dataset: identity
template: deepseek
cutoff_len: 2048
max_samples: 100000
overwrite_cache: true
preprocessing_num_workers: 16
dataloader_num_workers: 4

### output
output_dir: saves/Kllama_deepseekV3
logging_steps: 10
save_steps: 500
plot_loss: true
overwrite_output_dir: true
save_only_model: false
report_to: none  # choices: [none, wandb, tensorboard, swanlab, mlflow]

### train
per_device_train_batch_size: 1
gradient_accumulation_steps: 8
learning_rate: 1.0e-4
num_train_epochs: 3.0
lr_scheduler_type: cosine
warmup_ratio: 0.1
bf16: true
ddp_timeout: 180000000
resume_from_checkpoint: null

### ktransformers
use_kt: true # use KTransformers as LoRA sft backend
kt_optimize_rule: examples/kt_optimize_rules/DeepSeek-V3-Chat-sft-amx-multi-gpu.yaml
cpu_infer: 32
chunk_size: 8192

kt_optimize_rule controls placement strategy. See also ktransformers/optimize_rules. Naming hints (* = wildcard):

Example: DeepSeek-V3-Chat-sft-amx-multi-gpu.yaml = V3-Chat fine-tuning with AMX and 2-GPU model parallel.

We recommend AMX acceleration where available (lscpu | grep amx). AMX supports BF16/INT8. Example:

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- match:
    name: "^model\\.layers\\..*\\.mlp\\.experts$"
  replace:
    class: ktransformers.operators.experts.KTransformersExperts     # custom MoE Kernel with expert parallelism
    kwargs:
      prefill_device: "cpu"
      prefill_op: "KExpertsTorch"
      generate_device: "cpu"
      generate_op: "KSFTExpertsCPU"
      out_device: "cuda"
      backend: "AMXInt8" # or "AMXBF16" or "llamafile" (default)

Outputs go to output_dir in safetensors format plus adapter metadata for later loading.

Core Feature 2: Chat with the fine-tuned model (base + LoRA adapter)

Run the command: llamafactory-cli chat examples/inference/deepseek3_lora_sft_kt.yaml.

Use the safetensors adapter trained with KT for inference.

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model_name_or_path: opensourcerelease/DeepSeek-V3-bf16
adapter_name_or_path: saves/Kllama_deepseekV3
template: deepseek
infer_backend: ktransformers  # choices: [huggingface, vllm, sglang, ktransformers]
trust_remote_code: true

use_kt: true # use KTransformers as LoRA sft backend to inference
kt_optimize_rule: examples/kt_optimize_rules/DeepSeek-V3-Chat-sft-amx-multi-gpu.yaml
cpu_infer: 32
chunk_size: 8192

We also support GGUF adapters: for safetensors, set the directory; for GGUF, set the file path in adapter_name_or_path.

During loading, LLaMA-Factory maps layer names to KT’s naming. You’ll see logs like Loaded adapter weight: XXX -> XXX:

Core Feature 3: Batch inference + metrics (base + LoRA adapter)

Run the command: API_PORT=8000 llamafactory-cli api examples/inference/deepseek3_lora_sft_kt.yaml.

Invoke the KT fine-tuned adapter to provide the API; the usage logic of other APIs is consistent with the native LLaMA-Factory approach.

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model_name_or_path: opensourcerelease/DeepSeek-V3-bf16
adapter_name_or_path: saves/Kllama_deepseekV3
template: deepseek
infer_backend: ktransformers  # choices: [huggingface, vllm, sglang, ktransformers]
trust_remote_code: true

use_kt: true # use KTransformers as LoRA sft backend to inference
kt_optimize_rule: examples/kt_optimize_rules/DeepSeek-V3-Chat-sft-amx-multi-gpu.yaml
cpu_infer: 32
chunk_size: 8192

KT Fine-Tuning Speed

End-to-End Performance

Definitions

• step_time: wall-clock time for a full optimization step (tensor movement + Attention + MoE + other compute).
• tokens_per_step = GAS × qlen; token/s = tokens_per_step / step_time.

Settings: GAS=16, qlen=512 (→ tokens_per_step = 8192); LoRA (r=8, alpha=32, dropout=0.1); AMX enabled; GPU: RTX 4090, CPU: Intel Xeon Platinum 8488C.

Measured

• DeepSeek-V3-671B: step_time = 203 s → token/s ≈ 8192 / 203 ≈ 40.35
• DeepSeek-V2-Lite-14B: step_time = 36 s → token/s ≈ 8192 / 36 ≈ 227.6

GPU/CPU Memory Footprint

• DeepSeek-V3 (671B; 61 layers with 58 MoE): ~70 GB total GPU memory (multi-GPU), ~1.2–1.3 TB host memory.
• DeepSeek-V2-Lite (14B; 27 layers with 26 MoE): ~5.5 GB GPU memory, ~150 GB host memory.

Conclusion

By integrating KTransformers LoRA fine-tuning into LLaMA-Factory, we provide a practical guide for efficient training and deployment of MoE LLMs. KT brings cutting-edge optimizations (DeepSeek/Qwen/Kimi support with AMX-accelerated kernels), and LoRA enables customization under very low GPU memory. LLaMA-Factory offers a friendly, unified interface.

This integration (akin to Unsloth-style speedups) means even models with tens to hundreds of billions of parameters can be fine-tuned and deployed with low latency on commodity hardware. You get memory savings, speed-ups, and usability together. We encourage you to try LLaMA-Factory + KT for your next MoE project and follow this guide. Feedback is welcome!