API Reference

Overview

oneDNN uses the OpenCL runtime for GPU engines to interact with the GPU. Users may need to use oneDNN with other code that uses OpenCL. For that purpose, the library provides API extensions to interoperate with underlying OpenCL objects. This interoperability API is defined in the dnnl_ocl.hpp header.

The interoperability API is provided for two scenarios:

Construction of oneDNN objects based on existing OpenCL objects
Accessing OpenCL objects for existing oneDNN objects

The mapping between oneDNN and OpenCL objects is provided in the following table:

oneDNN object	OpenCL object(s)
Engine	`cl_device_id` and `cl_context`
Stream	`cl_command_queue`
Memory	`cl_mem`

The table below summarizes how to construct oneDNN objects based on OpenCL objects and how to query underlying OpenCL objects for existing oneDNN objects.

oneDNN object	API to construct oneDNN object	API to access OpenCL object(s)
Engine	dnnl::ocl_interop::make_engine(cl_device_id, cl_context)	dnnl::ocl_interop::get_device(const engine &) dnnl::ocl_interop::get_context(const engine &)
Stream	dnnl::ocl_interop::make_stream(const engine &, cl_command_queue)	dnnl::ocl_interop::get_command_queue(const stream &)
Memory	dnnl::memory(const memory::desc &, const engine &, cl_mem)	dnnl::ocl_interop::get_mem_object(const memory &)

Note: oneDNN follows retain/release OpenCL semantics when using OpenCL objects during construction. An OpenCL object is retained on construction and released on destruction. This ensures that the OpenCL object will not be destroyed while the oneDNN object stores a reference to it.; The access interfaces do not retain the OpenCL object. It is the user's responsibility to retain the returned OpenCL object if necessary.