问题
any one can tell me why Max work items for my gpu less than cpu and compute unit ??? is that mean performance for cpu is better than gpu
cpu : intel core i7 2.2GH gpu : amd radeon hd 6700M
Number of platforms: 2
Platform Profile: FULL_PROFILE
Platform Version: OpenCL 1.2 AMD-APP (1084.2)
Platform Name: AMD Accelerated Parallel Proces
sing
Platform Vendor: Advanced Micro Devices, Inc.
Platform Extensions: cl_khr_icd cl_amd_event_callbac
k cl_amd_offline_devices cl_khr_d3d10_sharing cl_khr_d3d11_sharing cl_khr_dx9_me
dia_sharing
Platform Profile: FULL_PROFILE
Platform Version: OpenCL 1.2
Platform Name: Intel(R) OpenCL
Platform Vendor: Intel(R) Corporation
Platform Extensions: cl_khr_fp64 cl_khr_icd cl_khr_g
lobal_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_intel_printf cl_ext_device_fission cl_intel_exec_by_local_thread cl_khr_gl_sh
aring cl_intel_dx9_media_sharing cl_khr_dx9_media_sharing cl_khr_d3d11_sharing
Platform Name: AMD Accelerated Parallel Proces
sing
Number of devices: 2
Device Type: CL_DEVICE_TYPE_GPU
Device ID: 4098
Max compute units: 6
Max work items dimensions: 3
Max work items[0]: 256
Max work items[1]: 256
Max work items[2]: 256
Max work group size: 256
Preferred vector width char: 16
Preferred vector width short: 8
Preferred vector width int: 4
Preferred vector width long: 2
Preferred vector width float: 4
Preferred vector width double: 0
Native vector width char: 16
Native vector width short: 8
Native vector width int: 4
Native vector width long: 2
Native vector width float: 4
Native vector width double: 0
Max clock frequency: 725Mhz
Address bits: 32
Max memory allocation: 536870912
Image support: Yes
Max number of images read arguments: 128
Max number of images write arguments: 8
Max image 2D width: 16384
Max image 2D height: 16384
Max image 3D width: 2048
Max image 3D height: 2048
Max image 3D depth: 2048
Max samplers within kernel: 16
Max size of kernel argument: 1024
Alignment (bits) of base address: 2048
Minimum alignment (bytes) for any datatype: 128
Single precision floating point capability
Denorms: No
Quiet NaNs: Yes
Round to nearest even: Yes
Round to zero: Yes
Round to +ve and infinity: Yes
IEEE754-2008 fused multiply-add: Yes
Cache type: None
Cache line size: 0
Cache size: 0
Global memory size: 2147483648
Constant buffer size: 65536
Max number of constant args: 8
Local memory type: Scratchpad
Local memory size: 32768
Kernel Preferred work group size multiple: 64
Error correction support: 0
Unified memory for Host and Device: 0
Profiling timer resolution: 1
Device endianess: Little
Available: Yes
Compiler available: Yes
Execution capabilities:
Execute OpenCL kernels: Yes
Execute native function: No
Queue properties:
Out-of-Order: No
Profiling : Yes
Platform ID: 02843864
Name: Turks
Vendor: Advanced Micro Devices, Inc.
Driver version: 1084.2 (VM)
Profile: FULL_PROFILE
Version: OpenCL 1.2 AMD-APP (1084.2)
Extensions: cl_khr_global_int32_base_atomic
s cl_khr_global_int32_extended_atomics cl_khr_local_int32_base_atomics cl_khr_lo
cal_int32_extended_atomics cl_khr_3d_image_writes cl_khr_byte_addressable_store
cl_khr_gl_sharing cl_ext_atomic_counters_32 cl_amd_device_attribute_query cl_amd
_vec3 cl_amd_printf cl_amd_media_ops cl_amd_popcnt cl_khr_d3d10_sharing cl_khr_d
x9_media_sharing
Device Type: CL_DEVICE_TYPE_CPU
Device ID: 4098
Max compute units: 8
Max work items dimensions: 3
Max work items[0]: 1024
Max work items[1]: 1024
Max work items[2]: 1024
Max work group size: 1024
Preferred vector width char: 16
Preferred vector width short: 8
Preferred vector width int: 4
Preferred vector width long: 2
Preferred vector width float: 8
Preferred vector width double: 4
Native vector width char: 16
Native vector width short: 8
Native vector width int: 4
Native vector width long: 2
Native vector width float: 8
Native vector width double: 4
Max clock frequency: 2195Mhz
Address bits: 32
Max memory allocation: 1073741824
Image support: Yes
Max number of images read arguments: 128
Max number of images write arguments: 8
Max image 2D width: 8192
Max image 2D height: 8192
Max image 3D width: 2048
Max image 3D height: 2048
Max image 3D depth: 2048
Max samplers within kernel: 16
Max size of kernel argument: 4096
Alignment (bits) of base address: 1024
Minimum alignment (bytes) for any datatype: 128
Single precision floating point capability
Denorms: Yes
Quiet NaNs: Yes
Round to nearest even: Yes
Round to zero: Yes
Round to +ve and infinity: Yes
IEEE754-2008 fused multiply-add: Yes
Cache type: Read/Write
Cache line size: 64
Cache size: 32768
Global memory size: 2147483648
Constant buffer size: 65536
Max number of constant args: 8
Local memory type: Global
Local memory size: 32768
Kernel Preferred work group size multiple: 1
Error correction support: 0
Unified memory for Host and Device: 1
Profiling timer resolution: 466
Device endianess: Little
Available: Yes
Compiler available: Yes
Execution capabilities:
Execute OpenCL kernels: Yes
Execute native function: Yes
Queue properties:
Out-of-Order: No
Profiling : Yes
Platform ID: 02843864
Name: Intel(R) Core(TM) i7-2670
QM CPU @ 2.20GHz
Vendor: GenuineIntel
Driver version: 1084.2 (sse2,avx)
Profile: FULL_PROFILE
Version: OpenCL 1.2 AMD-APP (1084.2)
Extensions: cl_khr_fp64 cl_amd_fp64 cl_khr_
global_int32_base_atomics cl_khr_global_int32_extended_atomics cl_khr_local_int3
2_base_atomics cl_khr_local_int32_extended_atomics cl_khr_3d_image_writes cl_khr
_byte_addressable_store cl_khr_gl_sharing cl_ext_device_fission cl_amd_device_at
tribute_query cl_amd_vec3 cl_amd_printf cl_amd_media_ops cl_amd_popcnt cl_khr_d3
d10_sharing
Platform Name: Intel(R) OpenCL
Number of devices: 1
Device Type: CL_DEVICE_TYPE_CPU
Device ID: 32902
Max compute units: 8
Max work items dimensions: 3
Max work items[0]: 1024
Max work items[1]: 1024
Max work items[2]: 1024
Max work group size: 1024
Preferred vector width char: 1
Preferred vector width short: 1
Preferred vector width int: 1
Preferred vector width long: 1
Preferred vector width float: 1
Preferred vector width double: 1
Native vector width char: 16
Native vector width short: 8
Native vector width int: 4
Native vector width long: 2
Native vector width float: 8
Native vector width double: 4
Max clock frequency: 2200Mhz
Address bits: 32
Max memory allocation: 536838144
Image support: Yes
Max number of images read arguments: 480
Max number of images write arguments: 480
Max image 2D width: 16384
Max image 2D height: 16384
Max image 3D width: 2048
Max image 3D height: 2048
Max image 3D depth: 2048
Max samplers within kernel: 480
Max size of kernel argument: 3840
Alignment (bits) of base address: 1024
Minimum alignment (bytes) for any datatype: 128
Single precision floating point capability
Denorms: Yes
Quiet NaNs: Yes
Round to nearest even: Yes
Round to zero: No
Round to +ve and infinity: No
IEEE754-2008 fused multiply-add: No
Cache type: Read/Write
Cache line size: 64
Cache size: 262144
Global memory size: 2147352576
Constant buffer size: 131072
Max number of constant args: 480
Local memory type: Global
Local memory size: 32768
Kernel Preferred work group size multiple: 128
Error correction support: 0
Unified memory for Host and Device: 1
Profiling timer resolution: 466
Device endianess: Little
Available: Yes
Compiler available: Yes
Execution capabilities:
Execute OpenCL kernels: Yes
Execute native function: Yes
Queue properties:
Out-of-Order: Yes
Profiling : Yes
Platform ID: 00401218
Name: Intel(R) Core(TM) i7-2670
QM CPU @ 2.20GHz
Vendor: Intel(R) Corporation
Driver version: 3.0.1.15216
Profile: FULL_PROFILE
Version: OpenCL 1.2 (Build 80752)
Extensions: cl_khr_fp64 cl_khr_icd cl_khr_g
lobal_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_intel_printf cl_ext_device_fission cl_intel_exec_by_local_thread cl_khr_gl_sh
aring cl_intel_dx9_media_sharing cl_khr_dx9_media_sharing cl_khr_d3d11_sharing
why see three device type two for cpu and one for gpu opencl for intel for cpu or built-in gpu i have two display adapters : AMD Radeon HD 6700M series Intel HD graphic family
回答1:
"How many cores/processing elements/hardware threads does my GPU have?" is a very frequently asked question for new GPGPU users. My usual response is "Why do you care?". There is no way to query the number of processing elements that a device has using the OpenCL API. Exactly what constitutes a processing element and a compute unit differs greatly between different architectures.
The reality is that it really doesn't matter how many processing elements your device has, since using this metric is a really bad way of estimating the performance of the device anyway. If you really need to know how fast the device is for your particular application, then you should benchmark it (either with your application directly, or with a micro-benchmark that has similar properties to your application).
To answer your other question: you have two OpenCL implementations on your system that are capable of using the CPU, Intel and AMD. Therefore, both platforms will report the CPU as an available OpenCL device.
来源：https://stackoverflow.com/questions/23125440/clinfo-device-cpu-gpu-info