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Transitioning from Intel MKL-DNN to oneDNN

To simplify library naming and differentiate it from Intel MKL, starting with version 1.1 the library name is changed to Deep Neural Network Library (DNNL).

Note

The subsequent library name change to oneAPI Deep Neural Network Library (oneDNN) does not impact API, environment variables, or build options.

There are some incompatibilities, described in the Broken Compatibility with Intel MKL-DNN section below.

Summary of Changes

In short, the migration can be as simple as just replacing all MKLDNN/mkldnn substrings with DNNL/dnnl.

Source Code Changes

All headers, functions, types, and namespaces are renamed by replacing mkldnn with dnnl. The macros with MKLDNN are replaced with DNNL counterparts.

An example of code with Intel MKL-DNN v1.0:

#include "mkldnn.hpp"

using namespace mkldnn;

mkldnn_memory_desc_t md;
if (md.format_kind == mkldnn_blocked) {}
conv.exec(stream, {{MKLDNN_ARGS_SRC, src}, ...});

The updated example with DNNL v1.1:

#include "dnnl.hpp"

using namespace dnnl;

dnnl_memory_desc_t md;
if (md.format_kind == dnnl_blocked) {}
conv.exec(stream, {{DNNL_ARGS_SRC, src}, ...});

To API compatibility with Intel MKL-DNN is based on include/mkldnn_dnnl_mangling.h header file that maps all Intel MKL-DNN symbols to DNNL ones using C preprocessor:

// ...
#define mkldnn_memory_desc_t           dnnl_memory_desc_t
#define mkldnn_memory_desc_init_by_tag dnnl_memory_desc_init_by_tag
// ...

This file is included to every former Intel MKL-DNN header files (for instance, see mkldnn.h) along with the DNNL counterpart.

Build Process

The changes to the build options are similar to the ones in the source code. All the options and namespaces with MKLDNN are replaced with DNNL :

Intel MKL-DNN

DNNL

MKLDNN (namespace)

DNNL (namespace)

MKLDNN_ARCH_OPT_FLAGS

DNNL_ARCH_OPT_FLAGS

MKLDNN_BUILD_EXAMPLES

DNNL_BUILD_EXAMPLES

MKLDNN_BUILD_FOR_CI

DNNL_BUILD_FOR_CI

MKLDNN_BUILD_TESTS

DNNL_BUILD_TESTS

MKLDNN_CPU_RUNTIME

DNNL_CPU_RUNTIME

MKLDNN_ENABLE_CONCURRENT_EXEC

DNNL_ENABLE_CONCURRENT_EXEC

MKLDNN_ENABLE_JIT_PROFILING

DNNL_ENABLE_JIT_PROFILING

MKLDNN_GPU_BACKEND

DNNL_GPU_BACKEND

MKLDNN_GPU_RUNTIME

DNNL_GPU_RUNTIME

MKLDNN_INSTALL_MODE

DNNL_INSTALL_MODE

MKLDNN_LIBRARY_TYPE

DNNL_LIBRARY_TYPE

MKLDNN_THREADING

DNNL_THREADING

MKLDNN_USE_CLANG_SANITIZER

DNNL_USE_CLANG_SANITIZER

MKLDNN_VERBOSE

DNNL_VERBOSE

MKLDNN_WERROR

DNNL_WERROR

You must switch to DNNL build options as well:

# Through find package
find_package(dnnl DNNL CONFIG REQUIRED)
target_link_libraries(project_app DNNL::dnnl)

# Or direct sub-project inclusion
add_subdirectory(${DNNL_DIR} DNNL)
include_directories(${DNNL_DIR}/include)
target_link_libraries(project_app dnnl)

Broken Compatibility with Intel MKL-DNN

Unfortunately, full compatibility after renaming is not implemented. DNNL is not compatible with Intel MKL-DNN in the following things:

  • ABI: An application or a library built with Intel MKL-DNN cannot switch on using DNNL without recompiling.

  • Microsoft* Visual Studio Solution files that are generated by cmake will be based on DNNL name only (e.g. MKLDNN.sln becomes DNNL.sln, and the former is no more generated).

Information for Developers

The implementation of renaming (several patches and scripts that rename the library) can be found here.

Advanced Topics Understanding Memory Formats