LLM-Barber

LLM-Barber: Block-Aware Rebuilder for Sparsity Mask in One-Shot for Large Language Models [arxiv]

Yupeng Su*, Ziyi Guan*, Xiaoqun Liu, Tianlai Jin, Dongkuan Wu, Graziano Chesi, Ngai Wong, Hao Yu (* indicates equal contribution)

Southern University of Science and Technology, University of Hong Kong

Transition from the layer-aware to block-aware error accumulation to achieve an optimized global solution. Rebuilding sparsity mask using a novel pruning metric based on weights multiplied by gradients.

Setup

To install, follow the instructions in the INSTALL.md file.

Usage

The scripts directory houses all Bash commands necessary to reproduce the primary findings presented in our paper.

The following command demonstrates pruning LLaMA-7B with LLM-Barber to achieve 50% unstructured sparsity based on initialization method Wanda.

python main.py \
    --model huggyllama/llama-7b \
    --prune_method wanda \
    --sparsity_ratio 0.5 --sparsity_type unstructured  \
    --prune_barber --prune_granularity output1 --threshold 0.01 \
    --save_model /path/to/save/model --save_ppl /path/to/save/ppl --save_zeroshot /path/to/save/zeroshot \
    --delete

Here's an overview of the arguments used in the command:

• --model: Specifies the LLaMA model to use from the Hugging Face model hub.
• --prune_method: Selects the pruning method, option [magnitude, sparsegpt, wanda].
• --sparsity_ratio: Sets the sparsity ratio, meaning the percentage of the weights will be pruned.
• --sparsity_type: Specifies the type of sparsity [unstructured,2:4,4:8].
• --prune_barber: This flag indicates that the model will be pruned with LLM-Barber.
• --prune_granularity: Specifies the granularity of the pruning, option [block, layer, output1, input1].
• --threshold: Sets the mask rebuilding ratio of LLM-Barber, default is 0.01.
• --save_model: Defines the directory where the pruned model will be saved.
• --save_ppl: Defines the directory where the perplexity results will be saved.
• --save_zeroshot: Defines the directory where the zero-shot results will be saved.
• --delete: This flag indicates that the pruned model should be deleted after the experiment.

This command will run the main.py script with the specified arguments, pruning the "huggyllama/llama-7b" model using initialization method Wanda with a sparsity ratio of 0.5 and unstructured sparsity. The results will be saved to the specified directories, and the pruned model will be deleted after the experiment.

To implement structured N:M sparsity, set the --sparsity_type argument to either "2:4" or "4:8". An example command is provided below.

python main.py \
    --model huggyllama/llama-7b \
    --prune_method wanda \
    --sparsity_ratio 0.5 --sparsity_type 2:4  \
    --prune_barber --prune_granularity output1 --threshold 0.01 \
    --save_model /path/to/save/model --save_ppl /path/to/save/ppl  \
    --delete

Acknowledgement

This repository is build upon the Wanda and SparseGPT repository.

License

This project is released under the MIT license. Please see the LICENSE file for more information.

Cite

If you find our work useful, please consider citing our paper:

@article{su2024llmbarber,
    author = {Yupeng Su and Ziyi Guan and Xiaoqun Liu and Tianlai Jin and Dongkuan Wu and Graziano Chesi and Ngai Wong and Hao Yu},
    title = {LLM-Barber: Block-Aware Rebuilder for Sparsity Mask in One-Shot for Large Language Models},
    year = {2024},
    eprint = {arXiv:2408.10631},
}