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_attri-
bute_query, cl_nv_device_attribute_query and cl_arm_core_id. Heuris-
tics 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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