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Atmapuri
Journeyman III

HD6950 and double precision!

Hi!

I have a Cayman HD6950 and it reports that fp64 extension is not supported. How can that be? Is that disabled in the drivers?

Thanks!
Atmapuri

 

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6 Replies
Meteorhead
Challenger

That depends on what OS-driver-SDK you are using.

Although reading the release notes of SDK 2.5 it says:

The Khronos FP64 extension is supported for the ATI Radeon™ HD 5900 and 5800 series, as well as the AMD FirePro™ V8800 and V8700 series.

6xxx cards are not mentioned for fp64 support. You might have to use cl_amd_fp64 extension for similar functionality.

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Hi!

Check for cl_amd_64f returns true, but check for cl_khr_fp64 returns false. Why? Double precision does not function right?

Thanks!
Atmapuri

 

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Originally posted by: Atmapuri Hi!

 

Check for cl_amd_64f returns true, but check for cl_khr_fp64 returns false. Why? Double precision does not function right? Thanks! Atmapuri

 

Atmapuri,

As per SDK2.5, both cl_amd_fp64 and cl_khr_fp64 are supported on this device.  

Are you using SDK2.5 or old?  

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Hi!

I am using SDK 2.5. I can only double confirm that:

clGetDeviceInfoStr(FDeviceID, CL_DEVICE_EXTENSIONS, Length(aStr), aStr, ParamSize));

Returns without cl_khr_fp64 listed. On the other hand, all double precision functions seem to work fine on CPU and GPU. (including sinh, cosh, tanh, which are listed as absent for cl_amd_64fp)

Is there a better way to check for support for double precision?

Thanks!
Atmapuri

 

 

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Originally posted by: Atmapuri Hi!

 

I am using SDK 2.5. I can only double confirm that:

 

clGetDeviceInfoStr(FDeviceID, CL_DEVICE_EXTENSIONS, Length(aStr), aStr, ParamSize));

 

Returns without cl_khr_fp64 listed. On the other hand, all double precision functions seem to work fine on CPU and GPU. (including sinh, cosh, tanh, which are listed as absent for cl_amd_64fp)

 

Is there a better way to check for support for double precision?

 

Could you please tell us your OS and Driver version?

Could you please run clinfo and paste output log here?

you can find clinfo at installerpath/bin/x86_64 or installerpath/bin/x86

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Below is clInfo. Note that cl_khr_fp64 is present for the CPU device but absent for both Caymans.

 

Number of platforms:                 1
  Platform Profile:                 FULL_PROFILE
  Platform Version:                 OpenCL 1.1 AMD-APP-SDK-v2.5 (732.1)
  Platform Name:                 AMD Accelerated Parallel Processing
  Platform Vendor:                 Advanced Micro Devices, Inc.
  Platform Extensions:                 cl_khr_icd cl_amd_event_callback cl_amd_offline_devices cl_khr_d3d10_sharing


  Platform Name:                 AMD Accelerated Parallel Processing
Number of devices:                 3
  Device Type:                     CL_DEVICE_TYPE_GPU
  Device ID:                     4098
  Board name:                     AMD Radeon HD 6900 Series
  Max compute units:                 22
  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:                 800Mhz
  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:                 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:             1024
  Alignment (bits) of base address:         32768
  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:                 1073741824
  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:                     000007FEF02A4348
  Name:                         Cayman
  Vendor:                     Advanced Micro Devices, Inc.
  Device OpenCL C version:             OpenCL C 1.1
  Driver version:                 CAL 1.4.1546 (VM)
  Profile:                     FULL_PROFILE
  Version:                     OpenCL 1.1 AMD-APP-SDK-v2.5 (732.1)
  Extensions:                     cl_amd_fp64 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_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


  Device Type:                     CL_DEVICE_TYPE_GPU
  Device ID:                     4098
  Board name:                     AMD Radeon HD 6900 Series
  Max compute units:                 22
  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:                 800Mhz
  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:                 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:             1024
  Alignment (bits) of base address:         32768
  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:                 1073741824
  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:                     000007FEF02A4348
  Name:                         Cayman
  Vendor:                     Advanced Micro Devices, Inc.
  Device OpenCL C version:             OpenCL C 1.1
  Driver version:                 CAL 1.4.1546 (VM)
  Profile:                     FULL_PROFILE
  Version:                     OpenCL 1.1 AMD-APP-SDK-v2.5 (732.1)
  Extensions:                     cl_amd_fp64 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_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


  Device Type:                     CL_DEVICE_TYPE_CPU
  Device ID:                     4098
  Board name:                     
  Max compute units:                 4
  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:             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:                 3300Mhz
  Address bits:                     64
  Max memory allocation:             2147483648
  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:         No
  Cache type:                     Read/Write
  Cache line size:                 64
  Cache size:                     32768
  Global memory size:                 8493379584
  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:             310
  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:                     000007FEF02A4348
  Name:                                Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz
  Vendor:                     GenuineIntel
  Device OpenCL C version:             OpenCL C 1.1
  Driver version:                 2.0
  Profile:                     FULL_PROFILE
  Version:                     OpenCL 1.1 AMD-APP-SDK-v2.5 (732.1)
  Extensions:                     cl_khr_fp64 cl_amd_fp64 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_int64_base_atomics cl_khr_int64_extended_atomics cl_khr_byte_addressable_store cl_khr_gl_sharing cl_ext_device_fission cl_amd_device_attribute_query cl_amd_vec3 cl_amd_media_ops cl_amd_popcnt cl_amd_printf cl_khr_d3d10_sharing


 

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