CMSIS-NN is a library containing kernel optimizations for Arm(R) Cortex(R)-M processors. To use CMSIS-NN optimized kernels instead of reference kernels, add OPTIMIZED_KERNEL_DIR=cmsis_nn to the make command line. See examples below.
For more information about the optimizations, check out CMSIS-NN documentation.
By default CMSIS-NN is built by code that is downloaded to the TFLM tree. It also possible to build CMSIS-NN code from an external path by specifying CMSIS_PATH=<../path> and CMSIS_NN_PATH=<../path>. Note that both CMSIS_PATH and CMSIS_NN_PATH is needed since CMSIS-NN has a dependency to CMSIS-Core. As a third option CMSIS-NN can be provided manually as an external library. The examples below will illustrate this.
In this example, the kernel conv unit test is built. For more information about this specific target, check out the Corstone-300 readme.
Downloaded CMSIS-NN code is built:
make -f tensorflow/lite/micro/tools/make/Makefile OPTIMIZED_KERNEL_DIR=cmsis_nn TARGET=cortex_m_corstone_300 TARGET_ARCH=cortex-m55 kernel_conv_test
External CMSIS-NN code is built:
make -f tensorflow/lite/micro/tools/make/Makefile OPTIMIZED_KERNEL_DIR=cmsis_nn CMSIS_PATH=<external/path/to/cmsis/> CMSIS_NN_PATH=<external/path/to/cmsis-nn/> TARGET=cortex_m_corstone_300 TARGET_ARCH=cortex-m55 kernel_conv_test
External CMSIS-NN library is linked in:
make -f tensorflow/lite/micro/tools/make/Makefile OPTIMIZED_KERNEL_DIR=cmsis_nn CMSIS_NN_LIBS=<path/to/cmsis-nn.a> CMSIS_PATH=<path/to/cmsis/> TARGET=cortex_m_corstone_300 TARGET_ARCH=cortex-m55 kernel_conv_test
Please note that performance and/or size might be affected when using an external CMSIS-NN library as different compiler options may have been used.
Also note that if specifying CMSIS_NN_LIBS but not CMSIS_PATH and or CMSIS_NN_PATH, headers and system/startup code from the default downloaded path of CMSIS would be used. So CMSIS_NN_LIBS, CMSIS_NN_PATH and CMSIS_PATH should have the same base path and if not there will be a build error.