CLINFO

Section: User Commands (1)
Updated: 2018-04-06
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NAME

clinfo - show OpenCL platforms and devices

SYNOPSIS

clinfo [options ...]

DESCRIPTION

clinfo prints all available information about all OpenCL platforms available on the system and the devices they expose.

OPTIONS

clinfo accepts the following options:

-a, --all-props: try to retrieve all properties, even those not officially supported (e.g. because they require specific extensions), but only show them if the property could be retrieved successfully; see also the LIMITATIONS section below; note that even though this may reveal hidden properties, there is no guarantee that the returned values are meaningful, nor that the corresponding feature is actually available at all;
-A, --always-all-props: like -a, but also show errors;
--human: produce human-friendly output; this is the default (except as noted below);
--raw: produce machine-friendly output; this is the default if clinfo is invoked with a name that contains the string ``raw'';
--offline: shows also offline devices for platforms that expose this feature;
-l, --list: list platforms and devices by name, with no (other) properties;
-h, -?: show usage;
--version, -v: show program version.

CONFORMING TO

OpenCL 1.1, OpenCL 1.2, OpenCL 2.0, OpenCL 2.1, OpenCL 2.2.

EXTENSIONS

Supported OpenCL extensions:

cl_khr_fp16, cl_khr_fp64, cl_amd_fp64, cl_APPLE_fp64_basic_ops: for information about support for half-precision and double-precision floating-point data types;
cl_khr_image2d_from_buffer: for information about the base address and pitch alignment requirements of buffers to be used as base for 2D images;
cl_khr_il_program: for information about the supported IL (Intermediate Language) representations;
cl_khr_spir: for information about the supported SPIR (Standard Portable Intermediate Representation) versions;
cl_khr_icd: for the suffix of vendor extensions functions;
cl_khr_subgroup_named_barrier: for the maximum number of named sub-group barriers;
cl_khr_terminate_context: for the terminate capabilities for the device;
cl_ext_device_fission: for device fission support in OpenCL 1.1 devices;
cl_ext_atomic_counters_32: cl_ext_atomic_counters_64 for the atomic counter extension;
cl_amd_device_attribute_query: for AMD-specific device attributes;
cl_amd_object_metadata: to show the maximum number of keys supported by the platform;
cl_amd_offline_devices: to show offline devices exposed by the platform, if requested (see --offline option);
cl_amd_copy_buffer_p2p: to show the number and IDs of available P2P devices;
cl_amd_svm: cl_arm_shared_virtual_memory for Shared Virtual Memory (SVM) capabilities in OpenCL 1.2 devices;
cl_nv_device_attribute_query: for NVIDIA-specific device attributes;
cl_intel_exec_by_local_thread: for the Intel extension allowing CPU devices to run kernels as part of the current host thread;
cl_intel_advanced_motion_estimation: for the version of the Intel Motion Estimation accelerator version;
cl_intel_device_side_avc_motion_estimation: for the version and supported features of Intel's device-side AVC Motion;
cl_intel_planar_yuv: for the maximum dimensions of planar YUV images;
cl_intel_simultaneous_sharing: for simultaneous CL/GL/DirectX context sharing (only partial support);
cl_intel_required_subgroup_size: to enumerate allowed sub-group sizes;
cl_altera_device_temperature: for the Altera extension to query the core temperature of the device;
cl_qcom_ext_host_ptr: for the QUALCOMM extension to query page size and required padding in external memory allocation.

NOTES

Some information is duplicated when available from multiple sources. Examples:

•: supported device partition types and domains as obtained using the cl_ext_device_fission extension typically match the ones obtained using the core OpenCL 1.2 device partition feature;
•: the preferred work-group size multiple matches the NVIDIA warp size (on NVIDIA devices) or the AMD wavefront width (on AMD devices).

Some floating-point configuration flags may only be meaningful for specific precisions and/or specific OpenCL versions. For example, CL_FP_CORRECTLY_ROUNDED_DIVIDE_SQRT is only relevant for single precision in OpenCL 1.2 devices.

The implementation-defined behavior for NULL platform or context properties is tested for the following API calls:

clGetPlatformInfo(): by trying to show the platform name;
clGetDeviceIDs(): by trying to enumerate devices; the corresponding platform (if any) is then detected by querying the device platform of the first device;
clCreateteContext(): by trying to create a context from a device from the previous list (if any), and a context from a device from a different platform;
clCreateteContextFromType(): by trying to create contexts for each device type (except DEFAULT).

EXPERIMENTAL FEATURES

Support for OpenCL 2.x properties is not fully tested.

Support for cl_khr_subgroup_named_barrier is experimental due to missing definitions in the official OpenCL headers.

Raw (machine-parsable) output is considered experimental, the output format might still undergo changes.

The properties of the ICD loader will also be queried if the clGetICDLoaderInfoOCLICD extension function is found.

Support for the properties exposed by cl_amd_copy_buffer_p2p is experimental.

Support for some (documented and undocumented) properties exposed by cl_amd_device_attribute_query is experimental (see also LIMITATIONS).

Support for the interop lists exposed by cl_intel_simultaneous_sharing is experimental.

The highest OpenCL version supported by the ICD loader is detected with some trivial heuristics (symbols found); a notice is output if this is lower than the highest platform OpenCL version, or if the detected version doesn't match the one declared by the ICD loader itself.

LIMITATIONS

OpenCL provides no explicit mean to detect the supported version of any extension exposed by a device, which makes it impossible to determine a priori if it will be possible to successfully query a device about a specific property. Additionally, the actual size and meaning of some properties are not officially declared anywhere.

Most notably, this affects extensions such as cl_amd_device_attribute_query and cl_nv_device_attribute_query. Heuristics based on standard version support are partially used in the code to determine which version may be supported.

Properties which are known to be affected by these limitations include:

CL_DEVICE_GLOBAL_FREE_MEMORY_AMD: documented in v3 of the cl_amd_device_attribute_query extension specification as being the global free memory in KBytes, without any explanation given on why there are two values;
CL_DEVICE_AVAILABLE_ASYNC_QUEUES_AMD: documented in v3 of the cl_amd_device_attribute_query extension specification, but not reported by drivers supporting other v3 properties. This has now been enabled for drivers assumed to support v4 of the same extension;
CL_DEVICE_TERMINATE_CAPABILITY_KHR: exposed by the cl_khr_terminate_context has changed value between OpenCL 1.x and 2.x, and it's allegedly a bitfield, whose values are however not defined anywhere.

BUGS

Please report any issues on the project tracker on GitHub