..  Licensed to the Apache Software Foundation (ASF) under one
    or more contributor license agreements.  See the NOTICE file
    distributed with this work for additional information
    regarding copyright ownership.  The ASF licenses this file
    to you under the Apache License, Version 2.0 (the
    "License"); you may not use this file except in compliance
    with the License.  You may obtain a copy of the License at

..    http://www.apache.org/licenses/LICENSE-2.0

..  Unless required by applicable law or agreed to in writing,
    software distributed under the License is distributed on an
    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    KIND, either express or implied.  See the License for the
    specific language governing permissions and limitations
    under the License.

.. _deploy-and-integration:

Deploy Models and Integrate TVM
===============================

This page contains guidelines on how to deploy TVM to various platforms
as well as how to integrate it with your project.

.. image::  https://tvm.apache.org/images/release/tvm_flexible.png

Build the TVM runtime library
-----------------------------

.. _build-tvm-runtime-on-target-device:

Unlike traditional deep learning frameworks. TVM stack is divided into two major components:

- TVM compiler, which does all the compilation and optimizations of the model
- TVM runtime, which runs on the target devices.

In order to integrate the compiled module, we **do not** need to build entire
TVM on the target device. You only need to build the TVM compiler stack on your 
desktop and use that to cross-compile modules that are deployed on the target device.

We only need to use a light-weight runtime API that can be integrated into various platforms.

For example, you can run the following commands to build the runtime API
on a Linux based embedded system such as Raspberry Pi:

.. code:: bash

    git clone --recursive https://github.com/apache/tvm tvm
    cd tvm
    mkdir build
    cp cmake/config.cmake build
    cd build
    cmake ..
    make runtime

Note that we type ``make runtime`` to only build the runtime library.

It is also possible to cross compile the runtime. Cross compiling
the runtime library should not be confused with cross compiling models
for embedded devices.

If you want to include additional runtime such as OpenCL,
you can modify ``config.cmake`` to enable these options.
After you get the TVM runtime library, you can link the compiled library

.. figure:: https://raw.githubusercontent.com/tlc-pack/web-data/main/images/dev/tvm_deploy_crosscompile.svg
   :align: center
   :width: 85%

A model (optimized or not by TVM) can be cross compiled by TVM for
different architectures such as ``aarch64`` on a ``x64_64`` host. Once the model
is cross compiled it is necessary to have a runtime compatible with the target
architecture to be able to run the cross compiled model.


Cross compile the TVM runtime for other architectures
-----------------------------------------------------

In the example :ref:`above <build-tvm-runtime-on-target-device>` the runtime library was 
compiled on a Raspberry Pi. Producing the runtime library can be done much faster on 
hosts that have high performace processors with ample resources (such as laptops, workstation) 
compared to a target devices such as a Raspberry Pi. In-order to cross compile the runtime the toolchain
for the target device must be installed. After installing the correct toolchain,
the main difference compared to compiling natively is to pass some additional command
line argument to cmake that specify a toolchain to be used. For reference
building the TVM runtime library on a modern laptop (using 8 threads) for ``aarch64``
takes around 20 seconds vs ~10 min to build the runtime on a Raspberry Pi 4.

cross-compile for aarch64
"""""""""""""""""""""""""

.. code-block:: bash

   sudo apt-get update
   sudo apt-get install gcc-aarch64-linux-gnu g++-aarch64-linux-gnu

.. code-block:: bash

    cmake .. \
        -DCMAKE_SYSTEM_NAME=Linux \
        -DCMAKE_SYSTEM_VERSION=1 \
        -DCMAKE_C_COMPILER=/usr/bin/aarch64-linux-gnu-gcc \
        -DCMAKE_CXX_COMPILER=/usr/bin/aarch64-linux-gnu-g++ \
        -DCMAKE_FIND_ROOT_PATH=/usr/aarch64-linux-gnu \
        -DCMAKE_FIND_ROOT_PATH_MODE_PROGRAM=NEVER \
        -DCMAKE_FIND_ROOT_PATH_MODE_LIBRARY=ONLY \
        -DMACHINE_NAME=aarch64-linux-gnu 

    make -j$(nproc) runtime

For bare metal ARM devices the following toolchain is quite handy to install instead of gcc-aarch64-linux-*

.. code-block:: bash

   sudo apt-get install gcc-multilib-arm-linux-gnueabihf g++-multilib-arm-linux-gnueabihf


cross-compile for RISC-V
"""""""""""""""""""""""""

.. code-block:: bash

   sudo apt-get update
   sudo apt-get install gcc-riscv64-linux-gnu g++-riscv64-linux-gnu


.. code-block:: bash

    cmake .. \
        -DCMAKE_SYSTEM_NAME=Linux \
        -DCMAKE_SYSTEM_VERSION=1 \
        -DCMAKE_C_COMPILER=/usr/bin/riscv64-linux-gnu-gcc \
        -DCMAKE_CXX_COMPILER=/usr/bin/riscv64-linux-gnu-g++ \
        -DCMAKE_FIND_ROOT_PATH=/usr/riscv64-linux-gnu \
        -DCMAKE_FIND_ROOT_PATH_MODE_PROGRAM=NEVER \
        -DCMAKE_FIND_ROOT_PATH_MODE_LIBRARY=ONLY \
        -DMACHINE_NAME=riscv64-linux-gnu 

    make -j$(nproc) runtime

The ``file`` command can be used to query the architecture of the produced runtime.


.. code-block:: bash

   file libtvm_runtime.so
   libtvm_runtime.so: ELF 64-bit LSB shared object, UCB RISC-V, version 1 (GNU/Linux), dynamically linked, BuildID[sha1]=e9ak845b3d7f2c126dab53632aea8e012d89477e, not stripped

    
Optimize and tune models for target devices
-------------------------------------------

The easiest and recommended way to test, tune and benchmark TVM kernels on
embedded devices is through TVM's RPC API.
Here are the links to the related tutorials.

- :ref:`tutorial-cross-compilation-and-rpc`
- :ref:`tutorial-deploy-model-on-rasp`

Deploy optimized model on target devices
----------------------------------------

After you finished tuning and benchmarking, you might need to deploy the model on the
target device without relying on RPC. See the following resources on how to do so.

.. toctree::
   :maxdepth: 2

   cpp_deploy
   android
   integrate
   hls
   arm_compute_lib
   tensorrt
   vitis_ai
   bnns

Additional Deployment How-Tos
-----------------------------

We have also developed a number of how-tos targeting specific devices, with
working Python code that can be viewed in a Jupyter notebook. These how-tos
describe how to prepare and deploy models to many of the supported backends.

.. toctree::
   :maxdepth: 1

   ../deploy_models/index