clGetDeviceInfo

Get information about an OpenCL device.

cl_int clGetDeviceInfo ( cl_device_id  device ,
  cl_device_info  param_name ,
  size_t  param_value_size ,
  void  *param_value ,
  size_t  *param_value_size_ret )

Parameters

device

May be a device returned by clGetDeviceIDs or a sub-device created by clCreateSubDevices. If device is a sub-device, the specific information for the sub-device will be returned. The information that can be queried using clGetDeviceInfo is specified in the table below.

param_value

A pointer to memory location where appropriate values for a given param_name as specified in the table below will be returned. If param_value is NULL, it is ignored.

param_value_size

Specifies the size in bytes of memory pointed to by param_value. This size in bytes must be ≥ size of return type specified in the table below.

param_value_size_ret

Returns the actual size in bytes of data being queried by param_value. If param_value_size_ret is NULL, it is ignored.

param_name

An enumeration constant that identifies the device information being queried. It can be one of the values as specified in the table below.

cl_device_info Return Type Description
CL_DEVICE_ADDRESS_BITS cl_uint The default compute device address space size specified as an unsigned integer value in bits. Currently supported values are 32 or 64 bits.
CL_DEVICE_AVAILABLE cl_bool Is CL_TRUE if the device is available and CL_FALSE if the device is not available.
CL_DEVICE_BUILT_IN_KERNELS char[] A semi-colon separated list of built-in kernels supported by the device. An empty string is returned if no built-in kernels are supported by the device.
CL_DEVICE_COMPILER_AVAILABLE cl_bool Is CL_FALSE if the implementation does not have a compiler available to compile the program source. Is CL_TRUE if the compiler is available. This can be CL_FALSE for the embedded platform profile only.
CL_DEVICE_DOUBLE_FP_CONFIG

cl_device_-

fp_config

Describes double precision floating-point capability of the OpenCL device. This is a bit-field that describes one or more of the following values:
  • CL_FP_DENORM - denorms are supported.
  • CL_FP_INF_NAN - INF and NaNs are supported.
  • CL_FP_ROUND_TO_NEAREST - round to nearest even rounding mode supported.
  • CL_FP_ROUND_TO_ZERO - round to zero rounding mode supported.
  • CL_FP_ROUND_TO_INF - round to positive and negative infinity rounding modes supported.
  • CP_FP_FMA - IEEE754-2008 fused multiply-add is supported.
  • CL_FP_SOFT_FLOAT - Basic floating-point operations (such as addition, subtraction, multiplication) are implemented in software.

Double precision is an optional feature so the mandated minimum double precision floating-point capability is 0.

If double precision is supported by the device, then the minimum double precision floatingpoint capability must be: CL_FP_FMA | CL_FP_ROUND_TO_NEAREST | CL_FP_ROUND_TO_ZERO | CL_FP_ROUND_TO_INF | CL_FP_INF_NAN | CL_FP_DENORM.

CL_DEVICE_ENDIAN_LITTLE cl_bool Is CL_TRUE if the OpenCL device is a little endian device and CL_FALSE otherwise.
CL_DEVICE_ERROR_CORRECTION_SUPPORT Return type: cl_bool Is CL_TRUE if the device implements error correction for all accesses to compute device memory (global and constant). Is CL_FALSE if the device does not implement such error correction.
CL_DEVICE_EXECUTION_CAPABILITIES

cl_device_-

exec_capabilities

Describes the execution capabilities of the device. This is a bit-field that describes one or more of the following values:

CL_EXEC_KERNEL - The OpenCL device can execute OpenCL kernels.

CL_EXEC_NATIVE_KERNEL - The OpenCL device can execute native kernels.

The mandated minimum capability is CL_EXEC_KERNEL.

CL_DEVICE_EXTENSIONS char[] Returns a space separated list of extension names (the extension names themselves do not contain any spaces) supported by the device. The list of extension names returned can be vendor supported extension names and one or more of the following Khronos approved extension names:

The following approved Khronos extension names must be returned by all device that support OpenCL C 1.2:


                        cl_khr_global_int32_base_atomics
                        cl_khr_global_int32_extended_atomics
                        cl_khr_local_int32_base_atomics
                        cl_khr_local_int32_extended_atomics
                        cl_khr_byte_addressable_store
                        cl_khr_fp64
                            (for backward compatibility if double precision is supported)
                        

Please refer to the OpenCL 1.2 Extension Specification for a detailed description of these extensions.

CL_DEVICE_GLOBAL_MEM_CACHE_SIZE cl_ulong Size of global memory cache in bytes.
CL_DEVICE_GLOBAL_MEM_CACHE_TYPE

cl_device_mem-

_cache_type

Type of global memory cache supported. Valid values are: CL_NONE, CL_READ_ONLY_CACHE, and CL_READ_WRITE_CACHE.
CL_DEVICE_GLOBAL_MEM_CACHELINE_SIZE cl_uint Size of global memory cache line in bytes.
CL_DEVICE_GLOBAL_MEM_SIZE cl_ulong Size of global device memory in bytes.
CL_DEVICE_HALF_FP_CONFIG

cl_device_-

fp_config

Describes the OPTIONAL half precision floating-point capability of the OpenCL device. This is a bit-field that describes one or more of the following values:
  • CL_FP_DENORM - denorms are supported.
  • CL_FP_INF_NAN - INF and NaNs are supported.
  • CL_FP_ROUND_TO_NEAREST - round to nearest even rounding mode supported.
  • CL_FP_ROUND_TO_ZERO - round to zero rounding mode supported.
  • CL_FP_ROUND_TO_INF - round to +ve and -ve infinity rounding modes supported.
  • CP_FP_FMA - IEEE754-2008 fused multiply-add is supported.
  • CL_FP_SOFT_FLOAT - Basic floating-point operations (such as addition, subtraction, multiplication) are implemented in software.

The required minimum half precision floating-point capability as implemented by this extension is CL_FP_ROUND_TO_ZERO or CL_FP_ROUND_TO_INF | CL_FP_INF_NAN.

CL_DEVICE_HOST_UNIFIED_MEMORY cl_bool Is CL_TRUE if the device and the host have a unified memory subsystem and is CL_FALSE otherwise.
CL_DEVICE_IMAGE_SUPPORT cl_bool Is CL_TRUE if images are supported by the OpenCL device and CL_FALSE otherwise.
CL_DEVICE_IMAGE2D_MAX_HEIGHT size_t Max height of 2D image in pixels. The minimum value is 8192 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE.
CL_DEVICE_IMAGE2D_MAX_WIDTH size_t Max width of 2D image or 1D image not created from a buffer object in pixels. The minimum value is 8192 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE.
CL_DEVICE_IMAGE3D_MAX_DEPTH size_t Max depth of 3D image in pixels. The minimum value is 2048 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE.
CL_DEVICE_IMAGE3D_MAX_HEIGHT size_t Max height of 3D image in pixels. The minimum value is 2048 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE.
CL_DEVICE_IMAGE3D_MAX_WIDTH size_t Max width of 3D image in pixels. The minimum value is 2048 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE.
CL_DEVICE_IMAGE_MAX_BUFFER_SIZE size_t Max number of pixels for a 1D image created from a buffer object. The minimum value is 65536 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE.
CL_DEVICE_IMAGE_MAX_ARRAY_SIZE size_t Max number of images in a 1D or 2D image array. The minimum value is 2048 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE
CL_DEVICE_LINKER_AVAILABLE cl_bool Is CL_FALSE if the implementation does not have a linker available. Is CL_TRUE if the linker is available. This can be CL_FALSE for the embedded platform profile only. This must be CL_TRUE if CL_DEVICE_COMPILER_AVAILABLE is CL_TRUE
CL_DEVICE_LOCAL_MEM_SIZE cl_ulong Size of local memory arena in bytes. The minimum value is 32 KB for devices that are not of type CL_DEVICE_TYPE_CUSTOM.
CL_DEVICE_LOCAL_MEM_TYPE

cl_device_-

local_mem_type

Type of local memory supported. This can be set to CL_LOCAL implying dedicated local memory storage such as SRAM, or CL_GLOBAL. For custom devices, CL_NONE can also be returned indicating no local memory support.
CL_DEVICE_MAX_CLOCK_FREQUENCY cl_uint Maximum configured clock frequency of the device in MHz.
CL_DEVICE_MAX_COMPUTE_UNITS cl_uint The number of parallel compute units on the OpenCL device. A work-group executes on a single compute unit. The minimum value is 1.
CL_DEVICE_MAX_CONSTANT_ARGS cl_uint Max number of arguments declared with the __constant qualifier in a kernel. The minimum value is 8 for devices that are not of type CL_DEVICE_TYPE_CUSTOM.
CL_DEVICE_MAX_CONSTANT_BUFFER_SIZE cl_ulong Max size in bytes of a constant buffer allocation. The minimum value is 64 KB for devices that are not of type CL_DEVICE_TYPE_CUSTOM.
CL_DEVICE_MAX_MEM_ALLOC_SIZE cl_ulong Max size of memory object allocation in bytes. The minimum value is max (1/4th of CL_DEVICE_GLOBAL_MEM_SIZE, 128*1024*1024) for devices that are not of type CL_DEVICE_TYPE_CUSTOM.
CL_DEVICE_MAX_PARAMETER_SIZE size_t Max size in bytes of the arguments that can be passed to a kernel. The minimum value is 1024 for devices that are not of type CL_DEVICE_TYPE_CUSTOM. For this minimum value, only a maximum of 128 arguments can be passed to a kernel.
CL_DEVICE_MAX_READ_IMAGE_ARGS cl_uint Max number of simultaneous image objects that can be read by a kernel. The minimum value is 128 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE.
CL_DEVICE_MAX_SAMPLERS cl_uint Maximum number of samplers that can be used in a kernel. The minimum value is 16 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE. (Also see sampler_t.)
CL_DEVICE_MAX_WORK_GROUP_SIZE size_t Maximum number of work-items in a work-group executing a kernel on a single compute unit, using the data parallel execution model. (Refer to clEnqueueNDRangeKernel). The minimum value is 1.
CL_DEVICE_MAX_WORK_ITEM_DIMENSIONS cl_uint Maximum dimensions that specify the global and local work-item IDs used by the data parallel execution model. (Refer to clEnqueueNDRangeKernel). The minimum value is 3 for devices that are not of type CL_DEVICE_TYPE_CUSTOM.
CL_DEVICE_MAX_WORK_ITEM_SIZES size_t[]

Maximum number of work-items that can be specified in each dimension of the work-group to clEnqueueNDRangeKernel.

Returns n size_t entries, where n is the value returned by the query for CL_DEVICE_MAX_WORK_ITEM_DIMENSIONS.

The minimum value is (1, 1, 1) for devices that are not of type CL_DEVICE_TYPE_CUSTOM.

CL_DEVICE_MAX_WRITE_IMAGE_ARGS cl_uint Max number of simultaneous image objects that can be written to by a kernel. The minimum value is 8 if CL_DEVICE_IMAGE_SUPPORT is CL_TRUE.
CL_DEVICE_MEM_BASE_ADDR_ALIGN cl_uint The minimum value is the size (in bits) of the largest OpenCL built-in data type supported by the device (long16 in FULL profile, long16 or int16 in EMBEDDED profile) for devices that are not of type CL_DEVICE_TYPE_CUSTOM.
CL_DEVICE_MIN_DATA_TYPE_ALIGN_SIZE cl_uint Deprecated in OpenCL 1.2. The smallest alignment in bytes which can be used for any data type.
CL_DEVICE_NAME char[] Device name string.
CL_DEVICE_NATIVE_VECTOR_WIDTH_CHAR

CL_DEVICE_NATIVE_VECTOR_WIDTH_SHORT

CL_DEVICE_NATIVE_VECTOR_WIDTH_INT

CL_DEVICE_NATIVE_VECTOR_WIDTH_LONG

CL_DEVICE_NATIVE_VECTOR_WIDTH_FLOAT

CL_DEVICE_NATIVE_VECTOR_WIDTH_DOUBLE

CL_DEVICE_NATIVE_VECTOR_WIDTH_HALF

cl_uint

Returns the native ISA vector width. The vector width is defined as the number of scalar elements that can be stored in the vector.

If double precision is not supported, CL_DEVICE_NATIVE_VECTOR_WIDTH_DOUBLE must return 0.

If the cl_khr_fp16 extension is not supported, CL_DEVICE_NATIVE_VECTOR_WIDTH_HALF must return 0.

CL_DEVICE_OPENCL_C_VERSION char[]

OpenCL C version string. Returns the highest OpenCL C version supported by the compiler for this device that is not of type CL_DEVICE_TYPE_CUSTOM. This version string has the following format:

OpenCL<space>C<space><major_version.minor_version><space><vendor-specific information>

The major_version.minor_version value returned must be 1.2 if CL_DEVICE_VERSION is OpenCL 1.2.

The major_version.minor_version value returned must be 1.1 if CL_DEVICE_VERSION is OpenCL 1.1.

CL_DEVICE_PARENT_DEVICE cl_device_id Returns the cl_device_id of the parent device to which this sub-device belongs. If device is a root-level device, a NULL value is returned.
CL_DEVICE_PARTITION_MAX_SUB_DEVICES cl_uint Returns the maximum number of sub-devices that can be created when a device is partitioned. The value returned cannot exceed CL_DEVICE_MAX_COMPUTE_UNITS.
CL_DEVICE_PARTITION_PROPERTIES

cl_device_partit-

ion_property[]

Returns the list of partition types supported by device. This is an array of cl_device_partition_property values drawn from the following list:
  • CL_DEVICE_PARTITION_EQUALLY
  • CL_DEVICE_PARTITION_BY_COUNTS
  • CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN
If the device does not support any partition types, a value of 0 will be returned.
CL_DEVICE_PARTITION_AFFINITY_DOMAIN

cl_device_aff-

inity_domain

Returns the list of supported affinity domains for partitioning the device using CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN. This is a bit-field that describes one or more of the following values:
  • CL_DEVICE_AFFINITY_DOMAIN_NUMA
  • CL_DEVICE_AFFINITY_DOMAIN_L4_CACHE
  • CL_DEVICE_AFFINITY_DOMAIN_L3_CACHE
  • CL_DEVICE_AFFINITY_DOMAIN_L2_CACHE
  • CL_DEVICE_AFFINITY_DOMAIN_L1_CACHE
  • CL_DEVICE_AFFINITY_DOMAIN_NEXT_PARTITIONABLE
If the device does not support any affinity domains, a value of 0 will be returned.
CL_DEVICE_PARTITION_TYPE

cl_device_part-

ition_property[]

Returns the properties argument specified in clCreateSubDevices if device is a subdevice. Otherwise the implementation may either return a param_value_size_ret of 0 i.e. there is no partition type associated with device or can return a property value of 0 (where 0 is used to terminate the partition property list) in the memory that param_value points to.
CL_DEVICE_PLATFORM cl_platform_id The platform associated with this device.
CL_DEVICE_PREFERRED_VECTOR_WIDTH_CHAR

CL_DEVICE_PREFERRED_VECTOR_WIDTH_SHORT

CL_DEVICE_PREFERRED_VECTOR_WIDTH_INT

CL_DEVICE_PREFERRED_VECTOR_WIDTH_LONG

CL_DEVICE_PREFERRED_VECTOR_WIDTH_FLOAT

CL_DEVICE_PREFERRED_VECTOR_WIDTH_DOUBLE

CL_DEVICE_PREFERRED_VECTOR_WIDTH_HALF

cl_uint

Preferred native vector width size for built-in scalar types that can be put into vectors. The vector width is defined as the number of scalar elements that can be stored in the vector.

If double precision is not supported, CL_DEVICE_PREFERRED_VECTOR_WIDTH_DOUBLE must return 0.

If the cl_khr_fp16 extension is not supported, CL_DEVICE_PREFERRED_VECTOR_WIDTH_HALF must return 0.

CL_DEVICE_PRINTF_BUFFER_SIZE size_t Maximum size of the internal buffer that holds the output of printf calls from a kernel. The minimum value for the FULL profile is 1 MB.
CL_DEVICE_PREFERRED_INTEROP_USER_SYNC cl_bool Is CL_TRUE if the device's preference is for the user to be responsible for synchronization, when sharing memory objects between OpenCL and other APIs such as DirectX, CL_FALSE if the device / implementation has a performant path for performing synchronization of memory object shared between OpenCL and other APIs such as DirectX
CL_DEVICE_PROFILE char[]

OpenCL profile string. Returns the profile name supported by the device (see note). The profile name returned can be one of the following strings:

FULL_PROFILE - if the device supports the OpenCL specification (functionality defined as part of the core specification and does not require any extensions to be supported).

EMBEDDED_PROFILE - if the device supports the OpenCL embedded profile.

CL_DEVICE_PROFILING_TIMER_RESOLUTION size_t Describes the resolution of device timer. This is measured in nanoseconds.
CL_DEVICE_QUEUE_PROPERTIES

cl_command_-

queue_properties

Describes the command-queue properties supported by the device. This is a bit-field that describes one or more of the following values:

CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE

CL_QUEUE_PROFILING_ENABLE

These properties are described in the table for clCreateCommandQueue. The mandated minimum capability is CL_QUEUE_PROFILING_ENABLE.

CL_DEVICE_REFERENCE_COUNT cl_uint Returns the device reference count. If the device is a root-level device, a reference count of one is returned.
CL_DEVICE_SINGLE_FP_CONFIG

cl_device_-

fp_config

Describes single precision floating-point capability of the device. This is a bit-field that describes one or more of the following values:

CL_FP_DENORM - denorms are supported

CL_FP_INF_NAN - INF and quiet NaNs are supported

CL_FP_ROUND_TO_NEAREST - round to nearest even rounding mode supported

CL_FP_ROUND_TO_ZERO - round to zero rounding mode supported

CL_FP_ROUND_TO_INF - round to +ve and -ve infinity rounding modes supported

CL_FP_FMA - IEEE754-2008 fused multiply-add is supported

CL_FP_CORRECTLY_ROUNDED_DIVIDE_SQRT - divide and sqrt are correctly rounded as defined by the IEEE754 specification.

CL_FP_SOFT_FLOAT - Basic floating-point operations (such as addition, subtraction, multiplication) are implemented in software.

The mandated minimum floating-point capability for devices that are not of type CL_DEVICE_TYPE_CUSTOM is CL_FP_ROUND_TO_NEAREST | CL_FP_INF_NAN.

CL_DEVICE_TYPE cl_device_type The OpenCL device type. Currently supported values are one of or a combination of: CL_DEVICE_TYPE_CPU, CL_DEVICE_TYPE_GPU, CL_DEVICE_TYPE_ACCELERATOR, CL_DEVICE_TYPE_DEFAULT, a combination of the above types, or CL_DEVICE_TYPE_CUSTOM.
CL_DEVICE_VENDOR char[] Vendor name string.
CL_DEVICE_VENDOR_ID cl_uint A unique device vendor identifier. An example of a unique device identifier could be the PCIe ID.
CL_DEVICE_VERSION char[]

OpenCL version string. Returns the OpenCL version supported by the device. This version string has the following format:

OpenCL<space><major_version.minor_version><space><vendor-specific information>

The major_version.minor_version value returned will be 1.1.

CL_DRIVER_VERSION char[] OpenCL software driver version string in the form major_number.minor_number.

Notes

CL_DEVICE_PROFILE: The platform profile returns the profile that is implemented by the OpenCL framework. If the platform profile returned is FULL_PROFILE, the OpenCL framework will support devices that are FULL_PROFILE and may also support devices that are EMBEDDED_PROFILE. The compiler must be available for all devices i.e. CL_DEVICE_COMPILER_AVAILABLE is CL_TRUE. If the platform profile returned is EMBEDDED_PROFILE, then devices that are only EMBEDDED_PROFILE are supported.

The device queries described the table above should return the same information for a root-level device i.e. a device returned by clGetDeviceIDs and any sub-devices created from this device except for the following queries:

  • CL_DEVICE_GLOBAL_MEM_CACHE_SIZE
  • CL_DEVICE_BUILT_IN_KERNELS
  • CL_DEVICE_PARENT_DEVICE
  • CL_DEVICE_PARTITION_TYPE
  • CL_DEVICE_REFERENCE_COUNT

Errors

clGetDeviceInfo returns CL_SUCCESS if the function is executed successfully. Otherwise, it returns the following:

  • CL_INVALID_DEVICE if device is not valid.
  • CL_INVALID_VALUE if param_name is not one of the supported values or if size in bytes specified by param_value_size is less than size of return type as shown in the table above and param_value is not a NULL value or if param_name is a value that is available as an extension and the corresponding extension is not supported by the device.
  • CL_OUT_OF_RESOURCES if there is a failure to allocate resources required by the OpenCL implementation on the device.
  • CL_OUT_OF_HOST_MEMORY if there is a failure to allocate resources required by the OpenCL implementation on the host.

Specification

OpenCL Specification

Also see

clGetDeviceIDs, cl_khr_fp64, __constant, clCreateCommandQueue, clRetainCommandQueue, clEnqueueNDRangeKernel

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