TensorRT-LLMs/examples/llm-api/llm_medusa_decoding.py
Yan Chunwei 9bd42ecf9b
[TRTLLM-5208][BREAKING CHANGE] chore: make pytorch LLM the default (#5312)
Signed-off-by: Superjomn <328693+Superjomn@users.noreply.github.com>
2025-06-20 03:01:10 +08:00

95 lines
4.7 KiB
Python

### Generate Text Using Medusa Decoding
import argparse
from pathlib import Path
from tensorrt_llm._tensorrt_engine import LLM
from tensorrt_llm.llmapi import (BuildConfig, KvCacheConfig,
MedusaDecodingConfig, SamplingParams)
def run_medusa_decoding(use_modelopt_ckpt=False, model_dir=None):
# Sample prompts.
prompts = [
"Hello, my name is",
"The president of the United States is",
"The capital of France is",
"The future of AI is",
]
# The end user can customize the sampling configuration with the SamplingParams class
sampling_params = SamplingParams(temperature=0.8, top_p=0.95)
# The end user can customize the build configuration with the BuildConfig class
build_config = BuildConfig(
max_batch_size=1,
max_seq_len=1024,
)
# The end user can customize the kv cache configuration with the KVCache class
kv_cache_config = KvCacheConfig(enable_block_reuse=True)
llm_kwargs = {}
if use_modelopt_ckpt:
# This is a Llama-3.1-8B combined with Medusa heads provided by TensorRT Model Optimizer.
# Both the base model (except lm_head) and Medusa heads have been quantized in FP8.
model = model_dir or "nvidia/Llama-3.1-8B-Medusa-FP8"
# ModelOpt ckpt uses 3 Medusa heads
speculative_config = MedusaDecodingConfig(
max_draft_len=63,
num_medusa_heads=3,
medusa_choices=[[0], [0, 0], [1], [0, 1], [2], [0, 0, 0], [1, 0], [0, 2], [3], [0, 3], \
[4], [0, 4], [2, 0], [0, 5], [0, 0, 1], [5], [0, 6], [6], [0, 7], [0, 1, 0], [1, 1], \
[7], [0, 8], [0, 0, 2], [3, 0], [0, 9], [8], [9], [1, 0, 0], [0, 2, 0], [1, 2], [0, 0, 3], \
[4, 0], [2, 1], [0, 0, 4], [0, 0, 5], [0, 1, 1], [0, 0, 6], [0, 3, 0], [5, 0], [1, 3], [0, 0, 7], \
[0, 0, 8], [0, 0, 9], [6, 0], [0, 4, 0], [1, 4], [7, 0], [0, 1, 2], [2, 0, 0], [3, 1], [2, 2], [8, 0], [0, 5, 0], [1, 5], [1, 0, 1], [0, 2, 1], [9, 0], [0, 6, 0], [1, 6], [0, 7, 0]]
)
else:
# In this path, base model and Medusa heads are stored and loaded separately.
model = "lmsys/vicuna-7b-v1.3"
# The end user can customize the medusa decoding configuration by specifying the
# speculative_model, max_draft_len, medusa heads num and medusa choices
# with the MedusaDecodingConfig class
speculative_config = MedusaDecodingConfig(
speculative_model="FasterDecoding/medusa-vicuna-7b-v1.3",
max_draft_len=63,
num_medusa_heads=4,
medusa_choices=[[0], [0, 0], [1], [0, 1], [2], [0, 0, 0], [1, 0], [0, 2], [3], [0, 3], [4], [0, 4], [2, 0], \
[0, 5], [0, 0, 1], [5], [0, 6], [6], [0, 7], [0, 1, 0], [1, 1], [7], [0, 8], [0, 0, 2], [3, 0], \
[0, 9], [8], [9], [1, 0, 0], [0, 2, 0], [1, 2], [0, 0, 3], [4, 0], [2, 1], [0, 0, 4], [0, 0, 5], \
[0, 0, 0, 0], [0, 1, 1], [0, 0, 6], [0, 3, 0], [5, 0], [1, 3], [0, 0, 7], [0, 0, 8], [0, 0, 9], \
[6, 0], [0, 4, 0], [1, 4], [7, 0], [0, 1, 2], [2, 0, 0], [3, 1], [2, 2], [8, 0], \
[0, 5, 0], [1, 5], [1, 0, 1], [0, 2, 1], [9, 0], [0, 6, 0], [0, 0, 0, 1], [1, 6], [0, 7, 0]]
)
# Add 'tensor_parallel_size=2' if using ckpt for
# a larger model like nvidia/Llama-3.1-70B-Medusa.
llm = LLM(model=model,
build_config=build_config,
kv_cache_config=kv_cache_config,
speculative_config=speculative_config,
**llm_kwargs)
outputs = llm.generate(prompts, sampling_params)
# Print the outputs.
for output in outputs:
prompt = output.prompt
generated_text = output.outputs[0].text
print(f"Prompt: {prompt!r}, Generated text: {generated_text!r}")
if __name__ == '__main__':
parser = argparse.ArgumentParser(
description="Generate text using Medusa decoding.")
parser.add_argument(
'--use_modelopt_ckpt',
action='store_true',
help="Use FP8-quantized checkpoint from TensorRT Model Optimizer.")
# TODO: remove this arg after ModelOpt ckpt is public on HF
parser.add_argument('--model_dir', type=Path, default=None)
args = parser.parse_args()
run_medusa_decoding(args.use_modelopt_ckpt, args.model_dir)