Name Strings

cl_intel_device_attribute_query

Contact

Ben Ashbaugh, Intel (ben 'dot' ashbaugh 'at' intel 'dot' com)

Contributors

Ben Ashbaugh, Intel
Maciej Dziuban, Intel
Rafik Saliev, Intel

Notice

Copyright (c) 2021 Intel Corporation. All rights reserved.

Status

Shipping

Version

Built On: 2021-09-30
Version: 1.0.0

Dependencies

This feature is written against the OpenCL API Specification Version V3.0.6.

This extension requires OpenCL 1.0.

Overview

This extension can be used to query additional information about Intel OpenCL devices. The additional information may be useful to tailor a specific workload to the properties of the device.

New API Functions

None.

New API Enums

Possible values accepted as the param_name parameter of clGetDeviceInfo, depending on the device type and the extension version. Additional queries may be added in subsequent versions of the extension:

/* For GPU devices, version 1.0.0: */

#define CL_DEVICE_IP_VERSION_INTEL                0x4250
#define CL_DEVICE_ID_INTEL                        0x4251
#define CL_DEVICE_NUM_SLICES_INTEL                0x4252
#define CL_DEVICE_NUM_SUB_SLICES_PER_SLICE_INTEL  0x4253
#define CL_DEVICE_NUM_EUS_PER_SUB_SLICE_INTEL     0x4254
#define CL_DEVICE_NUM_THREADS_PER_EU_INTEL        0x4255
#define CL_DEVICE_FEATURE_CAPABILITIES_INTEL      0x4256

Bitfield type describing the feature capabilities of a device. Additional feature flags may be added in subsequent versions of the extension.

typedef cl_bitfield         cl_device_feature_capabilities_intel;

/* For GPU devices, version 1.0.0: */

#define CL_DEVICE_FEATURE_FLAG_DP4A_INTEL         (1 << 0)
#define CL_DEVICE_FEATURE_FLAG_DPAS_INTEL         (1 << 1)

New API Types

None.

Modifications to the OpenCL API Specification

(Add to the list preceding Table 5 in Section 4.2 - Querying Devices)

The device queries described in the Device Queries table 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_NUM_SLICES_INTEL

(Add to Table 5 - OpenCL Device Queries in Section 4.2 - Querying Devices)
Table 5. List of supported param_names by clGetDeviceInfo
cl_device_info Return Type Description

CL_DEVICE_IP_VERSION_INTEL

cl_version

The IP version for the device. The meaning of this version is implementation-defined, but newer devices should have a higher version than older devices.

CL_DEVICE_ID_INTEL

cl_uint

A unique device identifier for the OpenCL device.

If the implementation is driven primarily by a PCI device with a PCI device ID, the low 16 bits of the device identifier must contain that PCI device ID, and the remaining bits must be set to zero. Otherwise, the choice of what to return may be dictated by operating system or platform policies - but should uniquely identify both the device version and any major configuration options (for example, core count in the case of multi-core devices).

CL_DEVICE_NUM_SLICES_INTEL

cl_uint

The number of slices in the device. A slice is a collection of sub-slices.

CL_DEVICE_NUM_SUB_SLICES_PER_SLICE_INTEL

cl_uint

The maximum number of sub-slices in one slice. A sub-slice is a collection of execution units (EUs), fixed-function units, and caches.

CL_DEVICE_NUM_EUS_PER_SUB_SLICE_INTEL

cl_uint

The maximum number of execution units (EUs) in one sub-slice. An execution unit is a multi-threaded processor that runs OpenCL kernels.

CL_DEVICE_NUM_THREADS_PER_EU_INTEL

cl_uint

The maximum number of threads that may be simultaneously resident on one execution unit (EU).

CL_DEVICE_FEATURE_CAPABILITIES_INTEL

cl_device_feature_capabilities_intel

Feature flags describing capabilities supported by the device.

Issues

  1. How to express cache sizes? Is it for the entire device?

    RESOLVED: The cache size query was removed in rev B, for now. If we decide to add it back, note that some caches are local to the device, while others are local to a sub-slice.

  2. Do we need a query for a "full device ID"?

    RESOLVED: This is useful but it will be added by a different extension.

  3. What should the return type be for the CL_DEVICE_IP_VERSION_INTEL query?

    RESOLVED: Using the OpenCL 3.0 cl_version type for now, but it could just as easily be interpreted as a plain cl_uint.

Revision History

Version Date Author Changes

1.0.0

2021-08-12

Ben Ashbaugh

Initial public revision