Implementation:Ggml org Ggml Opencl backend api

Metadata

Field	Value
Page Type	Implementation (API Doc)
Knowledge Sources	GGML
Domains	ML_Infrastructure, Tensor_Computing, GPU_Computing
Last Updated	2025-05-15 12:00 GMT

Overview

Public C header declaring the OpenCL backend interface for running tensor operations on GPUs and accelerators that support the OpenCL standard.

Description

ggml-opencl.h is a minimal header (26 lines) that exposes the OpenCL backend's public API. It declares five functions:

1. ggml_backend_opencl_init: Initializes and returns an OpenCL backend instance, discovering the best available OpenCL device.
2. ggml_backend_is_opencl: Type-checks whether a given backend handle is an OpenCL backend.
3. ggml_backend_opencl_buffer_type: Returns the buffer type for OpenCL device memory allocations.
4. ggml_backend_opencl_host_buffer_type: Returns the buffer type for host-pinned memory, enabling faster CPU-GPU transfers via DMA.
5. ggml_backend_opencl_reg: Returns the backend registration handle for the auto-discovery system.

All functions are marked with GGML_BACKEND_API for proper symbol visibility and are wrapped in extern "C" for C++ compatibility.

Usage

Include this header in application code to access the OpenCL backend. In most cases, the backend is loaded automatically via ggml_backend_load_all(), and this header is only needed for explicit initialization or type checking.

Code Reference

Source Location

GGML repo, file: include/ggml-opencl.h (26 lines).

Signatures

GGML_BACKEND_API ggml_backend_t ggml_backend_opencl_init(void);
GGML_BACKEND_API bool ggml_backend_is_opencl(ggml_backend_t backend);
GGML_BACKEND_API ggml_backend_buffer_type_t ggml_backend_opencl_buffer_type(void);
GGML_BACKEND_API ggml_backend_buffer_type_t ggml_backend_opencl_host_buffer_type(void);
GGML_BACKEND_API ggml_backend_reg_t ggml_backend_opencl_reg(void);

Import

#include "ggml-opencl.h"

I/O Contract

Inputs

Parameter	Type	Required	Description
(none for most functions)	--	--	ggml_backend_opencl_init, buffer type, and registration functions take no parameters.
backend	ggml_backend_t	Yes	Backend handle to type-check (for ggml_backend_is_opencl).

Outputs

Output	Type	Description
Backend handle	ggml_backend_t	Initialized OpenCL backend, or NULL on failure.
Type check	bool	true if the backend is OpenCL-based.
Buffer type	ggml_backend_buffer_type_t	Buffer type handle for device or host-pinned memory.
Registration	ggml_backend_reg_t	Registration handle for backend auto-discovery.

Usage Examples

#include "ggml-opencl.h"

// Initialize the OpenCL backend
ggml_backend_t backend = ggml_backend_opencl_init();

// Verify it is an OpenCL backend
if (backend && ggml_backend_is_opencl(backend)) {
    // Get the device buffer type for allocations
    ggml_backend_buffer_type_t buft = ggml_backend_opencl_buffer_type();

    // ... use backend for computation ...

    ggml_backend_free(backend);
}

Related Pages

• Principle:Ggml_org_Ggml_Backend_Interface
• Principle:Ggml_org_Ggml_OpenCL_GPU_Computation
• Implementation:Ggml_org_Ggml_Opencl_backend
• Principle:Ggml_org_Ggml_Backend_Initialization