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CLINFO(1)		    General Commands Manual		     CLINFO(1)

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 LIMITA-
	 TIONS section below; note that	even though  this  may	reveal	hidden
	 properties,  there is no guarantee that the returned values are mean-
	 ingful, 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 in-
	 voked with a name that	contains the string "raw";

       --json
	 outputs the raw data (cf. the --raw option) in	JSON  format;  support
	 for this option is experimental, as the representation	of some	of the
	 values	is not finalized;

       --offline
	 shows also offline devices for	platforms that expose this feature;

       --null-platform
	 tries	to  handle  the	NULL platform as a normal platform, retrieving
	 and showing its properties and	devices; this is in  addition  to  the
	 NULL  platform	 behavior  tests done at the end, and can be useful on
	 systems where there are no ICD	platforms, but	there  is  a  platform
	 hard-coded in the OpenCL library itself;

       -l, --list
	 list platforms	and devices by name, with no (other) properties;

       -dplatform_index:device_index
       --device	platform_index:device_index
	 only  show properties for the specified device	in the specified plat-
	 form;

       --prop property-name
	 only show properties whose symbolic name matches (contains as a  sub-
	 string) the given property-name; the name is normalized as upper-case
	 and  with  minus sign (-) replaced by underscore signs	(_); when this
	 flag is specified, raw	mode is	forced;

       -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, OpenCL 3.0.

EXTENSIONS
       Supported OpenCL	extensions:

       cl_khr_device_uuid
	 for the UUID, LUID and	node mask of the device;

       cl_khr_extended_versioning
	 for the extended platform, device, extension and IL versioned proper-
	 ties backported from OpenCL 3.0 to previous OpenCL versions;

       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  require-
	 ments of buffers to be	used as	base for 2D images;

       cl_khr_il_program
	 for information about the supported IL	(Intermediate Language)	repre-
	 sentations;

       cl_khr_spir
	 for  information about	the supported SPIR (Standard Portable Interme-
	 diate 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, cl_arm_controlled_kernel_termination
	 for the terminate capabilities	for the	device;

       cl_ext_device_fission
	 for device fission support in OpenCL 1.1 devices;

       cl_khr_pci_bus_info
	 for the PCI bus information  (see  also  cl_nv_device_attribute_query
	 and cl_amd_device_attribute_query)

       cl_ext_atomic_counters_32
       cl_ext_atomic_counters_64
	 for the atomic	counter	extension;

       cl_ext_cxx_for_opencl
	 for  the  version of the C++ for OpenCL language supported by the de-
	 vice compiler;

       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_arm_core_id
	 to show the (potentially sparse) list of the core IDs that the	device
	 may return;

       cl_arm_job_slot_selection
	 to show the (potentially sparse) list of available job	slots for com-
	 mand submission;

       cl_arm_scheduling_controls
	 to show the supported work scheduling controls	and the	available sets
	 of register allocations;

       cl_nv_device_attribute_query
	 for NVIDIA-specific device attributes;

       cl_intel_device_attribute_query
	 for Intel-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 Mo-
	 tion;

       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  sup-
	 port);

       cl_intel_required_subgroup_size
	 to enumerate allowed sub-group	sizes;

       cl_intel_command_queue_families
	 to  enumerate	the  available command queues and their	properties and
	 capabilities;

       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 us-
	 ing 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 spe-
       cific   precisions   and/or  specific  OpenCL  versions.	 For  example,
       CL_FP_CORRECTLY_ROUNDED_DIVIDE_SQRT is only relevant for	single	preci-
       sion in OpenCL 1.2 devices.

       The  implementation-defined behavior for	NULL platform or context prop-
       erties 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	 miss-
       ing 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  clGetICD-
       LoaderInfoOCLICD	extension function is found.

       Support for the properties exposed by cl_amd_copy_buffer_p2p is experi-
       mental.

       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 ver-
       sion 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_at-
       tribute_query,	 cl_nv_device_attribute_query	 and   cl_arm_core_id.
       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 spec-
	 ification  as being the global	free memory in KBytes, without any ex-
	 planation given on why	there are two values, although in  the	source
	 code  of  the	ROCm stack the second value is documented as being the
	 largest free block;

       CL_DEVICE_AVAILABLE_ASYNC_QUEUES_AMD
	 documented in v3 of the cl_amd_device_attribute_query extension spec-
	 ification, but	not reported by	drivers	supporting  other  v3  proper-
	 ties.	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
   General
       Please  report  any  issues  on	 the   project	 tracker   on	GitHub
       <http://github.com/Oblomov/clinfo>.

   LLVM	CommandLine errors
       If multiple OpenCL platforms using shared LLVM libraries	are present in
       the system, clinfo (and other OpenCL application) may crash with	errors
       to the tune of

	      :	CommandLine Error: Option '(some option	name)' registered more than once!
	      LLVM ERROR: inconsistency	in registered CommandLine options

       or  similar.  This is not an issue in clinfo, or	in any OpenCL platform
       or application, but it is due to	the way	LLVM handles its own  command-
       line  options  parsing.	 The issue has been reported upstream as issue
       #30587  <https://bugs.llvm.org/show_bug.cgi?id=30587>.	See  the  next
       point  for  possible workarounds	and assistance in identifying the con-
       flicting	platforms.

   Segmentation	faults
       Faulty OpenCL platforms may cause segmentation faults in	clinfo	during
       the  information	 gathering  phase, sometimes even before any output is
       shown. There is very little clinfo can do to avoid  this.  If  you  see
       this  happening,	 try disabling all platforms and then re-enabling them
       one by one until	you experience the crash again.	 Chances are the  last
       platform	 you  enabled is defective in some way (either by being	incom-
       patible with other platforms or by missing necessary components and not
       handling	their absence gracefully).

       To selectively enable/disable platforms,	one way	is to move  or	rename
       the *.icd files present in /etc/OpenCL/vendors/ and then	restoring them
       one by one. When	using the free-software	ocl-icd	OpenCL library,	a sim-
       ilar  effect  can  be  achieved	by  setting  the OPENCL_VENDOR_PATH or
       OCL_ICD_VENDORS environment variables, as documented  in	 libOpenCL(7).
       Other  implementations  of  libOpenCL  are known	to support OPENCL_VEN-
       DOR_PATH	too.

       Example
	 find /etc/OpenCL/vendors/ -name  '*.icd'  |  while  read  OPENCL_VEN-
	 DOR_PATH ; do clinfo -l > /dev/null ; echo "$?	${OPENCL_VENDOR_PATH}"
	 ; done

       This  one liner will run	clinfo -l for each platform individually (hid-
       ing the normal output), and report the .icd path	prefixed by 0 for suc-
       cessful runs, and a non-zero value for faulty platforms.

clinfo 3.0.23.01.25		  2023-01-25			     CLINFO(1)

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