Environmental Requirements

• cmake (version >=3.10 is recommended)
• protobuf (version >= 3.0 is required)
• gcc (version >= 4.9 is required)

Build Options

When compiling with cmake, you can modify the options in CMakeLists.txt:

• MNN_DEBUG

Defaults OFF, When OFF, remove symbols and build with optimizations.

• MNN_OPENMP

Defaults ON, When OFF, do not use openmp multi-thread.

• MNN_OPENCL

Defaults OFF, When ON, build the OpenCL backend, apply GPU according to setting the forward type to be MNN_FORWARD_OPENCL at inference time.

• MNN_OPENGL

Defaults OFF, When ON, build the OpenGL backend, apply GPU according to setting the forward type to be MNN_FORWARD_OPENGL at inference time.

• MNN_VULKAN

Defaults OFF, When ON, build the Vulkan backend, apply GPU according to setting the forward type to be MNN_FORWARD_VULKAN at inference time.

• MNN_METAL

Defaults OFF, When ON, build the Metal backend, apply GPU according to setting the forward type to be MNN_FORWARD_Metal at inference time, only effective on iOS/macOS.

Steps

Common Preparation

cd /path/to/MNN
./schema/generate.sh
./tools/script/get_model.sh # optional, models are needed only in demo project

Build on Host

mkdir build && cd build && cmake .. && make -j4

Then you will get the MNN library(libMNN.so)

Cross Compile

Download cross compile toolchain from Linaro. Examples:

aarch64

1. Download aarch64 toolchain

   mkdir -p linaro/aarch64
   cd linaro/aarch64
   wget http://releases.linaro.org/components/toolchain/binaries/latest-7/aarch64-linux-gnu/gcc-linaro-7.4.1-2019.02-x86_64_aarch64-linux-gnu.tar.xz
   tar xvf gcc-linaro-7.4.1-2019.02-x86_64_aarch64-linux-gnu.tar.xz

2. cmake & make

   export cross_compile_toolchain=/path/to/linaro/aarch64
   mkdir build && cd build
   cmake .. \
   -DCMAKE_SYSTEM_NAME=Linux \
   -DCMAKE_SYSTEM_VERSION=1 \
   -DCMAKE_SYSTEM_PROCESSOR=aarch64 \
   -DCMAKE_C_COMPILER=$cross_compile_toolchain/bin/aarch64-linux-gnu-gcc \
   -DCMAKE_CXX_COMPILER=$cross_compile_toolchain/bin/aarch64-linux-gnu-g++
   make -j4

arm

1. Download arm toolchain

   mkdir -p linaro/arm
   cd linaro/arm
   wget http://releases.linaro.org/components/toolchain/binaries/latest-7/arm-linux-gnueabi/gcc-linaro-7.4.1-2019.02-x86_64_arm-linux-gnueabi.tar.xz
   tar xvf gcc-linaro-7.4.1-2019.02-x86_64_arm-linux-gnueabi.tar.xz

2. cmake & make

   export cross_compile_toolchain=/path/to/linaro/arm
   mkdir build && cd build
   cmake .. \
   -DCMAKE_SYSTEM_NAME=Linux \
   -DCMAKE_SYSTEM_VERSION=1 \
   -DCMAKE_SYSTEM_PROCESSOR=arm \
   -DCMAKE_C_COMPILER=$cross_compile_toolchain/bin/arm-linux-gnueabi-gcc \
   -DCMAKE_CXX_COMPILER=$cross_compile_toolchain/bin/arm-linux-gnueabi-g++
   make -j4