exllama_v2.md

ExllamaV2 GPTQ Inference Framework

Integrated ExllamaV2 customized kernel into Fastchat to provide Faster GPTQ inference speed.

Note: Exllama not yet support embedding REST API.

Install ExllamaV2

Setup environment (please refer to this link for more details):

git clone https://github.com/turboderp/exllamav2
cd exllamav2
pip install -e .

Chat with the CLI:

python3 -m fastchat.serve.cli \
    --model-path models/vicuna-7B-1.1-GPTQ-4bit-128g \
    --enable-exllama

Start model worker:

# Download quantized model from huggingface
# Make sure you have git-lfs installed (https://git-lfs.com)
git lfs install
git clone https://huggingface.co/TheBloke/vicuna-7B-1.1-GPTQ-4bit-128g models/vicuna-7B-1.1-GPTQ-4bit-128g

# Load model with default configuration (max sequence length 4096, no GPU split setting).
python3 -m fastchat.serve.model_worker \
    --model-path models/vicuna-7B-1.1-GPTQ-4bit-128g \
    --enable-exllama

#Load model with max sequence length 2048, allocate 18 GB to CUDA:0 and 24 GB to CUDA:1.
python3 -m fastchat.serve.model_worker \
    --model-path models/vicuna-7B-1.1-GPTQ-4bit-128g \
    --enable-exllama \
    --exllama-max-seq-len 2048 \
    --exllama-gpu-split 18,24

--exllama-cache-8bit can be used to enable 8-bit caching with exllama and save some VRAM.

Performance

Reference: https://github.com/turboderp/exllamav2#performance

Model	Mode	Size	grpsz	act	V1: 3090Ti	V1: 4090	V2: 3090Ti	V2: 4090
Llama	GPTQ	7B	128	no	143 t/s	173 t/s	175 t/s	195 t/s
Llama	GPTQ	13B	128	no	84 t/s	102 t/s	105 t/s	110 t/s
Llama	GPTQ	33B	128	yes	37 t/s	45 t/s	45 t/s	48 t/s
OpenLlama	GPTQ	3B	128	yes	194 t/s	226 t/s	295 t/s	321 t/s
CodeLlama	EXL2 4.0 bpw	34B	-	-	-	-	42 t/s	48 t/s
Llama2	EXL2 3.0 bpw	7B	-	-	-	-	195 t/s	224 t/s
Llama2	EXL2 4.0 bpw	7B	-	-	-	-	164 t/s	197 t/s
Llama2	EXL2 5.0 bpw	7B	-	-	-	-	144 t/s	160 t/s
Llama2	EXL2 2.5 bpw	70B	-	-	-	-	30 t/s	35 t/s
TinyLlama	EXL2 3.0 bpw	1.1B	-	-	-	-	536 t/s	635 t/s
TinyLlama	EXL2 4.0 bpw	1.1B	-	-	-	-	509 t/s	590 t/s