此博客介绍如何将resnet101模型在CIFAR100数据集的分类任务，使用tensorrt部署。

完整代码如下

1.import以及数据加载、构建engine函数

import argparse
import osimport torch
from torch.utils.data import DataLoader
import torchvision
import torchvision.models as modelsimport timeimport numpy as np
import tensorrt as trt
import common
import torchvision.transforms as transformsTRT_LOGGER = trt.Logger()
os.environ["CUDA_VISIBLE_DEVICES"] = '0'  # 指定0号GPU可用# mean and std of cifar100 dataset
CIFAR100_TRAIN_MEAN = (0.5070751592371323, 0.48654887331495095, 0.4409178433670343)
CIFAR100_TRAIN_STD = (0.2673342858792401,0.2564384629170883, 0.27615047132568404)def get_test_dataloader(mean, std, batch_size=16, num_workers=2, shuffle=True):transform_test = transforms.Compose([transforms.ToTensor(),transforms.Normalize(mean, std)])cifar100_test = torchvision.datasets.CIFAR100(root='./data', train=False, download=True, transform=transform_test)cifar100_test_loader = DataLoader(cifar100_test, shuffle=shuffle, num_workers=num_workers, batch_size=batch_size)return cifar100_test_loaderdef ONNX_build_engine(onnx_file_path, trt_file):G_LOGGER = trt.Logger(trt.Logger.WARNING)explicit_batch = 1 << (int)(trt.NetworkDefinitionCreationFlag.EXPLICIT_BATCH)batch_size = 64  with trt.Builder(G_LOGGER) as builder, builder.create_network(explicit_batch) as network, \trt.OnnxParser(network, G_LOGGER) as parser:builder.max_batch_size = batch_sizeconfig = builder.create_builder_config()config.set_memory_pool_limit(trt.MemoryPoolType.WORKSPACE, common.GiB(1))config.set_flag(trt.BuilderFlag.FP16)print('Loading ONNX file from path {}...'.format(onnx_file_path))with open(onnx_file_path, 'rb') as model:print('Beginning ONNX file parsing')parser.parse(model.read())print('Completed parsing of ONNX file')print('Building an engine from file {}; this may take a while...'.format(onnx_file_path))profile = builder.create_optimization_profile()profile.set_shape("input", (1, 3, 32, 32),(1, 3, 32, 32), (batch_size, 3, 32, 32))config.add_optimization_profile(profile)engine = builder.build_serialized_network(network, config)print("Completed creating Engine")with open(trt_file, "wb") as f:f.write(engine)return engine

2.导入官方模型及CIFAR100数据集

if __name__ == '__main__':parser = argparse.ArgumentParser()parser.add_argument('-gpu', action='store_true',default=True, help='use gpu or not')parser.add_argument('-b', type=int, default=32,help='batch size for dataloader')args = parser.parse_args()print(args)cifar100_test_loader = get_test_dataloader(CIFAR100_TRAIN_MEAN, CIFAR100_TRAIN_STD,num_workers=1,batch_size=args.b)device = "cuda" if args.gpu else "cpu"net = models.resnet101(pretrained=True)net = net.to(device)# # print(net)net.eval()

3.不采用tensort的推断时间

#%%t1 = time.time()for n_iter, (image, label) in enumerate(cifar100_test_loader):pred = net(image.to(device))# print(pred.shape)t2 = time.time()print(t2-t1)

耗时约为8~9s。

4.采用tensort加速—使用tensorrt 库

4.1 导出onnx模型

#%% save onnx input = torch.rand([1, 3, 32, 32]).to(device)onnx_file = "resnet101.onnx"if  os.path.exists(onnx_file):os.remove(onnx_file)torch.onnx.export(net, input, onnx_file,input_names=['input'],  # the model's input namesoutput_names=['output'],dynamic_axes={'input': {0: 'batch_size'},'output': {0: 'batch_size'}},# opset_version=12,)print("onnx file generated!")

4.2 生成tensorrt engine 文件

# %%generate tensorrt engine filetrt_file = "resnet101.trt"ONNX_build_engine(onnx_file, trt_file)print("trt file generated!")

4.3 deserialize

    trt_file = "resnet101.trt"runtime = trt.Runtime(TRT_LOGGER)with open(trt_file, 'rb') as f:engine = runtime.deserialize_cuda_engine(f.read())print("Completed creating Engine")context = engine.create_execution_context()context.set_binding_shape(0, (16, 3, 32, 32))inputs, outputs, bindings, stream = common.allocate_buffers(engine, 32)

4.4 推断

    t1 = time.time()label_ls = []pred_ls = []for n_iter, (image, label) in enumerate(cifar100_test_loader):# print("iteration: {}\ttotal {} iterations".format(n_iter + 1, len(cifar100_test_loader)))# print(image)inputs[0].host = image.numpy()trt_outputs = common.do_inference(context, bindings=bindings, inputs=inputs, outputs=outputs, stream=stream, batch_size=32)label_ls.extend(label.numpy())pred_ls.extend(np.array(trt_outputs[0]).reshape([-1, 100]).argmax(1).tolist())# print((np.array(pred_ls)[:10000]==np.array(label_ls)[:10000]).sum())t2 = time.time()print(t2-t1)

耗时约为4.3s，是用我的笔记本 上的GPU RTX 3050可以实现两倍左右的加速。

5.采用tensort加速—使用torch2trt库

nvidia还有torch2trt Python包，可用于一键tensorrt加速。

其安装可参考https://github.com/NVIDIA-AI-IOT/torch2trt.

git clone https://github.com/NVIDIA-AI-IOT/torch2trt
cd torch2trt
python setup.py install

torch2trt的使用可参考github torch2trt：

    from torch2trt import torch2trtinputs = torch.rand([1, 3, 32, 32]).to(device)model_trt = torch2trt(net, [inputs], fp16_mode=True)t1 = time.time()label_ls = []pred_ls = []for n_iter, (image, label) in enumerate(cifar100_test_loader):output_trt = model_trt(image.to(device))t2 = time.time()print(t2-t1)

使用起来不要太easy！

完整代码可参考https://github.com/L0-zhang/tentorrt_demo/tree/main

参考文献

[1] csdn pytorch TensorRT 官方例子
[2] https://github.com/NVIDIA-AI-IOT/torch2trt
[3] https://github.com/L0-zhang/tentorrt_demo/tree/main