开源项目介绍：Native-LLM-for-Android

项目地址：Native-LLM-for-Android
创作活动时间：2025年

支持在 Android 设备上运行大型语言模型 （LLM） ，具体支持的模型包括：
DeepSeek-R1-Distill-Qwen: 1.5B
Qwen2.5-Instruct: 0.5B, 1.5B
Qwen2/2.5VL: 2B, 3B
MiniCPM-DPO/SFT: 1B, 2.7B
Gemma2-it: 2B
Phi3.5-mini-instruct: 3.8B
Llama-3.2-Instruct: 1B

Native-LLM-for-Android项目主要提供2个参考点，1、将LLM模型导出为onnx模型，2、在安卓端实现LLL模型的运行，本博文主要关注将llm导出为onnx推理（对现有的llm模型进行局部修改并导出），并以miniCPM模型为例进行测试。同时，Native-LLM-for-Android项目还有一些列模型量化代码可以学习。

1、模型运行性能

运行最快的模型是Llama3.2-1B-Instruct q8f32，达到25 token每秒，相应的硬件与os为 Nubia Z50（Android 13、8_Gen2-CPU）；其次是Distill-Qwen-1.5B q8f32，达到22 token每秒，相应的硬件与os为Xiaomi-14T-Pro （HyperOS 2、MediaTek_9300±CPU）；

2、核心功能

这里主要关注将llm导出为onnx脱离torch环境运行，因此对Android运行代码不予理会

2.1、分词器

分词器也就是Tokenizer ，一共两个功能：
1、将输入模型的文本，分为多个短词，并转换为token，
2、将模型输出的token转换为文本
需要注意的是，不同的llm模型分词规则是不一样的，同时对于的token编码规则也不同

一般运行onnx模型，都是基于Transformer库中的Tokenizer，这无法脱离torch环境。应该自行实现。

Native-LLM-for-Android项目中Tokenizer 依赖的是mnn-llm仓库中的实现.
具体代码链接为：
https://github.com/wangzhaode/mnn-llm/blob/master/src/tokenizer.cpp，是纯c++代码，与torch环境毫无关联

同时，在每一种模型的Android-onnx代码路径下，都有对于的Tokenizer的c++实现代码

2.2、导出onnx模型

在Native-LLM-for-Android项目下Export_ONNX目录中，每一个模型都有单独的导出代码

如Gemma模型的导出，分别执行A-B-C步骤，导出3个模型，在最后的导出代码中含onnx推理代码

其中关于QwenVL模型的导出较为复杂，需要对transformers库中modeling_qwen2_vl.py文件进行改写覆盖，将单个模型拆分为5个模型运行。其中A模型是VIT的主体部分，E模型是llm的主体部分，BCD模型是一些切片索引操作，被单独导出为模型。关于E模型导出有报错，可以参考https://github.com/DakeQQ/Native-LLM-for-Android/issues/10

如果导出模型报错

RuntimeError: The serialized model is larger than the 2GiB limit imposed by the protobuf library. Therefore the output file must be a file path, so that the ONNX external data can be written to the same directory. Please specify the output file name.

则尝试将torch版本降低到2.4.1
pip install torch2.4.1 torchvision0.19.1 torchaudio==2.4.1 --index-url https://download.pytorch.org/whl/cu121

2.3、onnx模型量化

关于onnx模型量化，可以参考：https://blog.csdn.net/m0_63642362/article/details/124741589，根据介绍，onnx量化可以分为动态量化与静态量化，动态量化在推理时根据输入数据动态计算缩放因子与零点；静态量化，使用校准数据集离线计算缩放因子（Scale）和零点（Zero Point）。通常，建议对 RNN 和基于 Transformer 的模型使用动态量化，对 CNN 模型使用静态量化

在Native-LLM-for-Android-main\Do_Quantize\Dynamic_Quant 目录下有多个模型量化代码，具体如下图所示

q8_f16的量化代码如下所示，可以看到对于大尺寸的模型的量化有一个关键参数项 is_large_model

import os
import gc
import glob
import sys
import onnx
import torch
import subprocess
import onnx.version_converter
from onnxsim import simplify
from onnxslim import slim
from onnxruntime.quantization import QuantType, quantize_dynamic
from onnxruntime.transformers.optimizer import optimize_model
from transformers import AutoModelForCausalLM# Path Setting
original_folder_path = r"C:\Users\Downloads\Model_ONNX"                          # The original folder.
quanted_folder_path = r"C:\Users\Downloads\Model_ONNX_Optimized"                 # The optimized folder.
model_path = os.path.join(original_folder_path, "Model.onnx")                    # The original fp32 model path.
quanted_model_path = os.path.join(quanted_folder_path, "Model_Optimized.onnx")   # The optimized model stored path.
download_path = r'C:\Users\Downloads\Qwen2-1.5B-Instruct'                        # Set the folder path where the LLM whole project downloaded, otherwise set "NONE".
use_gpu = True                                                                   # If true, the transformers.optimizer will remain the FP16 processes.
provider = 'CPUExecutionProvider'                                                # ['CPUExecutionProvider', 'CUDAExecutionProvider']
use_low_memory_mode_in_Android = False                                           # If you need to use low memory mode on Android, please set it to True.# Preprocess, it also cost alot of memory during preprocess, you can close this command and keep quanting. Call subprocess may get permission failed on Windows system.
# (optional process)
# subprocess.run([f'python -m onnxruntime.quantization.preprocess --auto_merge --all_tensors_to_one_file --input {model_path} --output {quanted_folder_path}'], shell=True)# Start Quantize
quantize_dynamic(model_input=model_path,model_output=quanted_model_path,per_channel=True,                                        # True for model accuracy but cost a lot of time during quanting process.reduce_range=False,                                      # True for some x86_64 platform.weight_type=QuantType.QInt8,                            # It is recommended using uint8 + Symmetric Falseextra_options={'ActivationSymmetric': False,             # True for inference speed. False may keep more accuracy.'WeightSymmetric': False,                 # True for inference speed. False may keep more accuracy.'EnableSubgraph': True,                   # True for more quant.'ForceQuantizeNoInputCheck': False,       # True for more quant.'MatMulConstBOnly': True                  # False for more quant. Sometime, the inference speed may get worse.},nodes_to_exclude=None,                                   # Specify the node names to exclude quant process. Example: nodes_to_exclude={'/Gather'}use_external_data_format=True                            # Save the model into two parts.
)model_size_bytes = sys.getsizeof(onnx.load(model_path).SerializeToString())
model_size_gb = model_size_bytes * 9.31322575e-10            # 1 / (1024 * 1024 * 1024)
if model_size_gb > 2.0:is_large_model = True
else:is_large_model = True if use_low_memory_mode_in_Android else False# ONNX Model Optimizer
slim(model=quanted_model_path,output_model=quanted_model_path,no_shape_infer=False,   # True for more optimize but may get errors.skip_fusion_patterns=False,no_constant_folding=False,save_as_external_data=is_large_model,verbose=False
)if download_path == "NONE":num_heads = 0    # defaulthidden_size = 0  # default
else:if ('vl' in download_path.lower()) & ('qwen' in download_path.lower()):if "2.5" in download_path or "3b" in download_path.lower():from transformers import Qwen2_5_VLForConditionalGenerationmodel = Qwen2_5_VLForConditionalGeneration.from_pretrained(download_path, torch_dtype=torch.float16, device_map='cpu', trust_remote_code=True, low_cpu_mem_usage=True).eval()else:from transformers import Qwen2VLForConditionalGenerationmodel = Qwen2VLForConditionalGeneration.from_pretrained(download_path, torch_dtype=torch.float16, device_map='cpu', trust_remote_code=True, low_cpu_mem_usage=True).eval()else:model = AutoModelForCausalLM.from_pretrained(download_path, torch_dtype=torch.float16, device_map='cpu', trust_remote_code=True, low_cpu_mem_usage=True).eval()num_heads = model.config.num_attention_headshidden_size = model.config.hidden_sizedel modelgc.collect()# transformers.optimizer
model = optimize_model(quanted_model_path,use_gpu=use_gpu,opt_level=2,num_heads=num_heads,hidden_size=hidden_size,provider=provider,verbose=False,model_type='bert')
model.convert_float_to_float16(keep_io_types=True,force_fp16_initializers=True,use_symbolic_shape_infer=True,  # True for more optimize but may get errors.op_block_list=['DynamicQuantizeLinear', 'DequantizeLinear', 'DynamicQuantizeMatMul', 'Range', 'MatMulIntegerToFloat']
)
model.save_model_to_file(quanted_model_path, use_external_data_format=is_large_model)
del model
gc.collect()# onnxslim 2nd
slim(model=quanted_model_path,output_model=quanted_model_path,no_shape_infer=False,   # True for more optimize but may get errors.skip_fusion_patterns=False,no_constant_folding=False,save_as_external_data=is_large_model,verbose=False
)# Upgrade the Opset version. (optional process)
model = onnx.load(quanted_model_path)
model = onnx.version_converter.convert_version(model, 21)
onnx.save(model, quanted_model_path, save_as_external_data=is_large_model)if is_large_model:pattern = os.path.join(quanted_folder_path, '*.data')files_to_delete = glob.glob(pattern)for file_path in files_to_delete:try:os.remove(file_path)except Exception as e:print(f"Error deleting {file_path}: {e}")# It is not recommended to convert an FP16 ONNX model to the ORT format because this process adds a Cast operation to convert the FP16 process back to FP32.

3、导出minicpm模型onnx推理

3.1 下载模型

pip install modelscope

基于modelscope 库可以下载MiniCPM-2B-dpo-fp16模型

from modelscope import snapshot_download
model_dir = snapshot_download('OpenBMB/MiniCPM-2B-dpo-fp16',cache_dir=".cache_dir")

3.2 导出onnx模型

这里以MiniCPM-2B-split导出方式为例

先在命令行进入 F:\Native-LLM-for-Android-main\Export_ONNX\MiniCPM\MiniCPM-2B-split 目录

然后创建，model_a，model_b两个目录，用于存储2个onnx模型，并将代码修改为以下形式

最后在命令行中执行 python .\MiniCPM_Export.py 即可实现模型导出为onnx，并进行推理测试

这里可以发现代码的推理速度居然为0.375token/s，简直巨慢。

按照单个模型导出，并进行推理测试，发现效果如下所示，可以发现性能有6倍的提升，这表明数据通信也占据了大量的耗时。

3.3 单独运行onnx

基于以下代码可以运行onnx模型，但无法脱离transformers库，除非手写tokenizer实现分词，并实现token与文本的对应关系。

import numpy as np
import onnxruntime
from transformers import AutoModelForCausalLM, AutoTokenizer
import timepath = 'F:\DMT\.cache_dir\OpenBMB\MiniCPM-2B-dpo-fp16'  # Set the folder path where the MiniCPM whole project downloaded.
onnx_model_A = r'F:\Native-LLM-for-Android-main\Export_ONNX\MiniCPM\MiniCPM-2B-single\model_q8_f16\MiniCPM_part_A_Optimized.onnx'  # Assign a path where the exported MiniCPM_part_A stored.# Run the exported model by ONNX Runtime
query = "山东省最高的山是哪座山, 它比黄山高还是矮？差距多少？"
max_seq_len = 1024  # Please modify the same variable, which declared in the modified modeling_minicpm.py on line 1008, at the same time.
num_heads = 36
head_dim = 64
num_key_value_heads = 36
num_layers = 40
hidden_size = 2304max_single_chat_length = 341  # It a adjustable value, but must less than max_seq_len.
tokenizer = AutoTokenizer.from_pretrained(path, trust_remote_code=True)# ONNX Runtime settings
session_opts = onnxruntime.SessionOptions()
session_opts.log_severity_level = 3  # error level, it a adjustable value.
session_opts.inter_op_num_threads = 0  # Run different nodes with num_threads. Set 0 for auto.
session_opts.intra_op_num_threads = 0  # Under the node, execute the operators with num_threads. Set 0 for auto.
session_opts.enable_cpu_mem_arena = True  # True for execute speed; False for less memory usage.
session_opts.execution_mode = onnxruntime.ExecutionMode.ORT_SEQUENTIAL
session_opts.graph_optimization_level = onnxruntime.GraphOptimizationLevel.ORT_ENABLE_ALL
session_opts.add_session_config_entry("session.intra_op.allow_spinning", "1")
session_opts.add_session_config_entry("session.inter_op.allow_spinning", "1")ort_session_A = onnxruntime.InferenceSession(onnx_model_A, sess_options=session_opts, providers=['CPUExecutionProvider'])
in_name_A = ort_session_A.get_inputs()
out_name_A = ort_session_A.get_outputs()
in_name_A0 = in_name_A[0].name
in_name_A1 = in_name_A[1].name
in_name_A2 = in_name_A[2].name
in_name_A3 = in_name_A[3].name
in_name_A4 = in_name_A[4].name
in_name_A5 = in_name_A[5].name
out_name_A0 = out_name_A[0].name
out_name_A1 = out_name_A[1].name
out_name_A2 = out_name_A[2].name# Pre-process inputs
prompt = tokenizer.apply_chat_template([{"role": 'user', "content": query}], tokenize=False, add_generation_prompt=False)
token = tokenizer(prompt, return_tensors='pt')['input_ids']
ids_len = token.shape[1] + np.zeros(1, dtype=np.int64)
input_ids = np.zeros(max_seq_len, dtype=np.int32)
input_ids[:ids_len[0]] = token[0, :]
attention_mask = np.array([-65504.0], dtype=np.float32)
history_len = np.zeros(1, dtype=np.int64)
past_key_states_A = np.zeros((num_layers, num_key_value_heads, max_seq_len, head_dim), dtype=np.float16)
past_values_states_A = past_key_states_A
num_decode = 0
print('\nTest Question: ' + query + "\n\nMiniCPM Answering:\n")# Start to run LLM
start_time = time.time()
while history_len < max_single_chat_length:token_id, past_key_states_A, past_values_states_A = ort_session_A.run([out_name_A0, out_name_A1, out_name_A2],{in_name_A0: input_ids,in_name_A1: attention_mask,in_name_A2: past_key_states_A,in_name_A3: past_values_states_A,in_name_A4: history_len,in_name_A5: ids_len})if token_id == 2:  # the stop_id in MiniCPM is "2"breakelse:history_len[0] += ids_len[0]ids_len[0] = 1num_decode += 1attention_mask[0] = 0.0input_ids[0] = token_idprint(tokenizer.decode(token_id), end="", flush=True)
end_time = time.time()
print(f"\n\nDecode: {(num_decode / (end_time - start_time)):.3f} token/s")