test_tensorrt.txt

import pycuda.autoinit
import numpy as np
import pycuda.driver as cuda
import tensorrt as trt
import torch
import os
import time
from PIL import Image
import cv2
import torchvision

filename = '/home/ubuntu/TM2/photo/4.png'
max_batch_size = 1
onnx_model_path = "model.onnx"
base_size=512

TRT_LOGGER = trt.Logger()  # This logger is required to build an engine

class HostDeviceMem(object):
    def __init__(self, host_mem, device_mem):
        """Within this context, host_mom means the cpu memory and device means the GPU memory
        """
        self.host = host_mem
        self.device = device_mem

    def __str__(self):
        return "Host:\n" + str(self.host) + "\nDevice:\n" + str(self.device)

    def __repr__(self):
        return self.__str__()


def allocate_buffers(engine):
    inputs = []
    outputs = []
    bindings = []
    stream = cuda.Stream()
    for binding in engine:
        size = trt.volume(engine.get_binding_shape(binding)) * engine.max_batch_size
        dtype = trt.nptype(engine.get_binding_dtype(binding))
        # Allocate host and device buffers
        host_mem = cuda.pagelocked_empty(size, dtype)
        device_mem = cuda.mem_alloc(host_mem.nbytes)
        # Append the device buffer to device bindings.
        bindings.append(int(device_mem))
        # Append to the appropriate list.
        if engine.binding_is_input(binding):
            inputs.append(HostDeviceMem(host_mem, device_mem))
        else:
            outputs.append(HostDeviceMem(host_mem, device_mem))
    return inputs, outputs, bindings, stream


def get_engine(max_batch_size=1, onnx_file_path="", engine_file_path="", \
               fp16_mode=False, int8_mode=False, save_engine=False,
               ):
    """Attempts to load a serialized engine if available, otherwise builds a new TensorRT engine and saves it."""

    def build_engine(max_batch_size, save_engine):
        """Takes an ONNX file and creates a TensorRT engine to run inference with"""
        network_creation_flag = 1 << int(trt.NetworkDefinitionCreationFlag.EXPLICIT_PRECISION)
        network_creation_flag |= 1 << int(trt.NetworkDefinitionCreationFlag.EXPLICIT_BATCH)
        with trt.Builder(TRT_LOGGER) as builder, \
                builder.create_network(network_creation_flag) as network, \
                trt.OnnxParser(network, TRT_LOGGER) as parser:

            builder.max_workspace_size = 1 << 30  # Your workspace size
            builder.max_batch_size = max_batch_size
            # pdb.set_trace()
            builder.fp16_mode = fp16_mode  # Default: False
            builder.int8_mode = int8_mode  # Default: False
            if int8_mode:
                # To be updated
                raise NotImplementedError

            # Parse model file
            if not os.path.exists(onnx_file_path):
                quit('ONNX file {} not found'.format(onnx_file_path))

            print('Loading ONNX file from path {}...'.format(onnx_file_path))
            with open(onnx_file_path, 'rb') as model:
                print('Beginning ONNX file parsing')
                if not parser.parse(model.read()):
                    print('ERROR: Failed to parse the ONNX file.')
                    for error in range(parser.num_errors):
                        print(parser.get_error(error))

            print("num_layers after parsing: {}".format(network.num_layers))

            last_layer = network.get_layer(network.num_layers - 1)
            # Check if last layer recognizes it's output
            print("the shape of the output: {}".format(last_layer.get_output(0).shape))
            if not last_layer.get_output(0):
            # If not, then mark the output using TensorRT API
                network.mark_output(last_layer.get_output(0))

            print('Completed parsing of ONNX file')
            print('Building an engine from file {}; this may take a while...'.format(onnx_file_path))

            engine = builder.build_cuda_engine(network)
            print("Completed creating Engine")

            if save_engine:
                with open(engine_file_path, "wb") as f:
                    f.write(engine.serialize())
            return engine

    if os.path.exists(engine_file_path):
        # If a serialized engine exists, load it instead of building a new one.
        print("Reading engine from file {}".format(engine_file_path))
        with open(engine_file_path, "rb") as f, trt.Runtime(TRT_LOGGER) as runtime:
            return runtime.deserialize_cuda_engine(f.read())
    else:
        return build_engine(max_batch_size, save_engine)


def do_inference(context, bindings, inputs, outputs, stream, batch_size=1):
    # Transfer data from CPU to the GPU.
    [cuda.memcpy_htod_async(inp.device, inp.host, stream) for inp in inputs]
    # Run inference.
    context.execute_async(batch_size=batch_size, bindings=bindings, stream_handle=stream.handle)
    # Transfer predictions back from the GPU.
    [cuda.memcpy_dtoh_async(out.host, out.device, stream) for out in outputs]
    # Synchronize the stream
    stream.synchronize()
    # Return only the host outputs.
    return [out.host for out in outputs]


def postprocess_the_outputs(h_outputs, shape_of_output):
    h_outputs = h_outputs.reshape(*shape_of_output)
    return h_outputs


image = Image.open(filename).convert('RGB')
if base_size:
    image = image.resize(size=(base_size, base_size), resample=Image.BILINEAR)
image = np.expand_dims(image, axis=0)

# These two modes are dependent on hardwares
fp16_mode = False
int8_mode = False
trt_engine_path = './model_fp16_{}_int8_{}.trt'.format(fp16_mode, int8_mode)
# Build an engine
engine = get_engine(max_batch_size, onnx_model_path, trt_engine_path, fp16_mode, int8_mode)
# Create the context for this engine
context = engine.create_execution_context()
# Allocate buffers for input and output
inputs, outputs, bindings, stream = allocate_buffers(engine) # input, output: host # bindings

# Do inference
shape_of_output = (max_batch_size, 4, 512, 512)
# Load data to the buffer
inputs[0].host = image.reshape(-1)

# inputs[1].host = ... for multiple input
t1 = time.time()
trt_outputs = do_inference(context, bindings=bindings, inputs=inputs, outputs=outputs, stream=stream) # numpy data
t2 = time.time()
feat = postprocess_the_outputs(trt_outputs[0], shape_of_output)

print('TensorRT ok')

print("Inference time with the TensorRT engine: {}".format(t2-t1))

print('All completed!')