tutorials/frontend/deploy_model_on_rasp.py

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"""
.. _tutorial-deploy-model-on-rasp:

Deploy the Pretrained Model on Raspberry Pi
===========================================
**Author**: `Ziheng Jiang <https://ziheng.org/>`_, \
            `Hiroyuki Makino <https://makihiro.github.io/>`_

This is an example of using Relay to compile a ResNet model and deploy
it on Raspberry Pi.
"""

import tvm
from tvm import te
import tvm.relay as relay
from tvm import rpc
from tvm.contrib import util, graph_runtime as runtime
from tvm.contrib.download import download_testdata

######################################################################
# .. _build-tvm-runtime-on-device:
#
# Build TVM Runtime on Device
# ---------------------------
#
# The first step is to build the TVM runtime on the remote device.
#
# .. note::
#
#   All instructions in both this section and next section should be
#   executed on the target device, e.g. Raspberry Pi. And we assume it
#   has Linux running.
#
# Since we do compilation on local machine, the remote device is only used
# for running the generated code. We only need to build tvm runtime on
# the remote device.
#
# .. code-block:: bash
#
#   git clone --recursive https://github.com/apache/incubator-tvm tvm
#   cd tvm
#   mkdir build
#   cp cmake/config.cmake build
#   cd build
#   cmake ..
#   make runtime -j4
#
# After building runtime successfully, we need to set environment varibles
# in :code:`~/.bashrc` file. We can edit :code:`~/.bashrc`
# using :code:`vi ~/.bashrc` and add the line below (Assuming your TVM
# directory is in :code:`~/tvm`):
#
# .. code-block:: bash
#
#   export PYTHONPATH=$PYTHONPATH:~/tvm/python
#
# To update the environment variables, execute :code:`source ~/.bashrc`.

######################################################################
# Set Up RPC Server on Device
# ---------------------------
# To start an RPC server, run the following command on your remote device
# (Which is Raspberry Pi in our example).
#
#   .. code-block:: bash
#
#     python -m tvm.exec.rpc_server --host 0.0.0.0 --port=9090
#
# If you see the line below, it means the RPC server started
# successfully on your device.
#
#    .. code-block:: bash
#
#      INFO:root:RPCServer: bind to 0.0.0.0:9090
#

######################################################################
# Prepare the Pre-trained Model
# -----------------------------
# Back to the host machine, which should have a full TVM installed (with LLVM).
#
# We will use pre-trained model from
# `MXNet Gluon model zoo <https://mxnet.incubator.apache.org/api/python/gluon/model_zoo.html>`_.
# You can found more details about this part at tutorial :ref:`tutorial-from-mxnet`.

from mxnet.gluon.model_zoo.vision import get_model
from PIL import Image
import numpy as np

# one line to get the model
block = get_model("resnet18_v1", pretrained=True)

######################################################################
# In order to test our model, here we download an image of cat and
# transform its format.
img_url = "https://github.com/dmlc/mxnet.js/blob/master/data/cat.png?raw=true"
img_name = "cat.png"
img_path = download_testdata(img_url, img_name, module="data")
image = Image.open(img_path).resize((224, 224))


def transform_image(image):
    image = np.array(image) - np.array([123.0, 117.0, 104.0])
    image /= np.array([58.395, 57.12, 57.375])
    image = image.transpose((2, 0, 1))
    image = image[np.newaxis, :]
    return image


x = transform_image(image)

######################################################################
# synset is used to transform the label from number of ImageNet class to
# the word human can understand.
synset_url = "".join(
    [
        "https://gist.githubusercontent.com/zhreshold/",
        "4d0b62f3d01426887599d4f7ede23ee5/raw/",
        "596b27d23537e5a1b5751d2b0481ef172f58b539/",
        "imagenet1000_clsid_to_human.txt",
    ]
)
synset_name = "imagenet1000_clsid_to_human.txt"
synset_path = download_testdata(synset_url, synset_name, module="data")
with open(synset_path) as f:
    synset = eval(f.read())

######################################################################
# Now we would like to port the Gluon model to a portable computational graph.
# It's as easy as several lines.

# We support MXNet static graph(symbol) and HybridBlock in mxnet.gluon
shape_dict = {"data": x.shape}
mod, params = relay.frontend.from_mxnet(block, shape_dict)
# we want a probability so add a softmax operator
func = mod["main"]
func = relay.Function(func.params, relay.nn.softmax(func.body), None, func.type_params, func.attrs)

######################################################################
# Here are some basic data workload configurations.
batch_size = 1
num_classes = 1000
image_shape = (3, 224, 224)
data_shape = (batch_size,) + image_shape

######################################################################
# Compile The Graph
# -----------------
# To compile the graph, we call the :any:`relay.build` function
# with the graph configuration and parameters. However, You cannot to
# deploy a x86 program on a device with ARM instruction set. It means
# Relay also needs to know the compilation option of target device,
# apart from arguments :code:`net` and :code:`params` to specify the
# deep learning workload. Actually, the option matters, different option
# will lead to very different performance.

######################################################################
# If we run the example on our x86 server for demonstration, we can simply
# set it as :code:`llvm`. If running it on the Raspberry Pi, we need to
# specify its instruction set. Set :code:`local_demo` to False if you want
# to run this tutorial with a real device.

local_demo = True

if local_demo:
    target = tvm.target.Target("llvm")
else:
    target = tvm.target.arm_cpu("rasp3b")
    # The above line is a simple form of
    # target = tvm.target.Target('llvm -device=arm_cpu -model=bcm2837 -mtriple=armv7l-linux-gnueabihf -mattr=+neon')

with tvm.transform.PassContext(opt_level=3):
    lib = relay.build(func, target, params=params)

# After `relay.build`, you will get three return values: graph,
# library and the new parameter, since we do some optimization that will
# change the parameters but keep the result of model as the same.

# Save the library at local temporary directory.
tmp = util.tempdir()
lib_fname = tmp.relpath("net.tar")
lib.export_library(lib_fname)

######################################################################
# Deploy the Model Remotely by RPC
# --------------------------------
# With RPC, you can deploy the model remotely from your host machine
# to the remote device.

# obtain an RPC session from remote device.
if local_demo:
    remote = rpc.LocalSession()
else:
    # The following is my environment, change this to the IP address of your target device
    host = "10.77.1.162"
    port = 9090
    remote = rpc.connect(host, port)

# upload the library to remote device and load it
remote.upload(lib_fname)
rlib = remote.load_module("net.tar")

# create the remote runtime module
ctx = remote.cpu(0)
module = runtime.GraphModule(rlib["default"](ctx))
# set input data
module.set_input("data", tvm.nd.array(x.astype("float32")))
# run
module.run()
# get output
out = module.get_output(0)
# get top1 result
top1 = np.argmax(out.asnumpy())
print("TVM prediction top-1: {}".format(synset[top1]))